//獲取數(shù)據(jù)庫(kù)連接
try (Connection conn = DriverManager.getConnection("mysqlUrl", "userName", "password")) {
    String sql = "SELECT * FROM  t_user WHERE name = ?";
    //預(yù)編譯SQL
    try (PreparedStatement preparedStatement = conn.prepareStatement(sql)) {
        //參數(shù)設(shè)置與執(zhí)行
        preparedStatement.setString(1, "vivo");
        preparedStatement.execute(sql);
        //獲取結(jié)果集
        try (ResultSet resultSet = preparedStatement.getResultSet()) {
            while (resultSet.next()) {
                //處理結(jié)果
            }
        }
    }
}

org.apache.shardingsphere.shardingjdbc.jdbc.core.statement#execute
    public boolean execute() throws SQLException {
        try {
            clearPrevious();
            //解析+路由+重寫(xiě) 內(nèi)部調(diào)用BasePrepareEngine#prepare方法
            prepare();
            initPreparedStatementExecutor();
            //執(zhí)行
            return preparedStatementExecutor.execute();
        } finally {
            clearBatch();
        }
    }
 
org.apache.shardingsphere.underlying.pluggble.prepare.BasePrepareEngine#prepare
    public ExecutionContext prepare(final String sql, final List<Object> parameters) {
        List<Object> clonedParameters = cloneParameters(parameters);
        //解析+路由(executeRoute內(nèi)部先進(jìn)行解析再執(zhí)行路由)
        RouteContext routeContext = executeRoute(sql, clonedParameters);
        ExecutionContext result = new ExecutionContext(routeContext.getSqlStatementContext());
        //重寫(xiě)
        result.getExecutionUnits().addAll(executeRewrite(sql, clonedParameters, routeContext));
        if (properties.<Boolean>getValue(ConfigurationPropertyKey.SQL_SHOW)) {
            SQLLogger.logSQL(sql, properties.<Boolean>getValue(ConfigurationPropertyKey.SQL_SIMPLE), result.getSqlStatementContext(), result.getExecutionUnits());
        }
        return result;
    }
 
org.apache.shardingsphere.shardingjdbc.jdbc.core.statement.ShardingPreparedStatement#getResultSet
    public ResultSet getResultSet() throws SQLException {
        if (null != currentResultSet) {
            return currentResultSet;
        }
        if (executionContext.getSqlStatementContext() instanceof SelectStatementContext || executionContext.getSqlStatementContext().getSqlStatement() instanceof DALStatement) {
            List<ResultSet> resultSets = getResultSets();
            //歸并結(jié)果集
            MergedResult mergedResult = mergeQuery(getQueryResults(resultSets));
            currentResultSet = new ShardingResultSet(resultSets, mergedResult, this, executionContext);
        }
        return currentResultSet;
    }

org.apache.shardingsphere.underlying.route.DataNodeRouter#createRouteContext#96
    private RouteContext createRouteContext(final String sql, final List<Object> parameters, final boolean useCache) {
        //解析引擎解析SQL
        SQLStatement sqlStatement = parserEngine.parse(sql, useCache);
        try {
            SQLStatementContext sqlStatementContext = SQLStatementContextFactory.newInstance(metaData.getSchema(), sql, parameters, sqlStatement);
            return new RouteContext(sqlStatementContext, parameters, new RouteResult());
            // TODO should pass parameters for master-slave
        } catch (final IndexOutOfBoundsException ex) {
            return new RouteContext(new CommonSQLStatementContext(sqlStatement), parameters, new RouteResult());
        }
    }
 
org.apache.shardingsphere.sql.parser.SQLParserEngine#parse0#72
    private SQLStatement parse0(final String sql, final boolean useCache) {
        //緩存
        if (useCache) {
            Optional<SQLStatement> cachedSQLStatement = cache.getSQLStatement(sql);
            if (cachedSQLStatement.isPresent()) {
                return cachedSQLStatement.get();
            }
        }
        //根據(jù)數(shù)據(jù)庫(kù)類(lèi)型和sql生成解析樹(shù)
        ParseTree parseTree = new SQLParserExecutor(databaseTypeName, sql).execute().getRootNode();
        //ParseTreeVisitor的visit方法對(duì)解析樹(shù)進(jìn)行處理得到SQLStatement
      SQLStatement result = (SQLStatement) ParseTreeVisitorFactory.newInstance(databaseTypeName, VisitorRule.valueOf(parseTree.getClass())).visit(parseTree);
        if (useCache) {
            cache.put(sql, result);
        }
        return result;
    }

public final class SelectStatement extends DMLStatement {
    // 字段
    private ProjectionsSegment projections;
    // 表
    private final Collection<TableReferenceSegment> tableReferences = new LinkedList<>();
    // where
    private WhereSegment where;
    // groupBy
    private GroupBySegment groupBy;
    // orderBy
    private OrderBySegment orderBy;
    // limit
    private LimitSegment limit;
    // 父statement
    private SelectStatement parentStatement;
    // lock
    private LockSegment lock;
}

public final class SelectStatementContext extends CommonSQLStatementContext<SelectStatement> implements TableAvailable, WhereAvailable {
     
    private final TablesContext tablesContext;
     
    private final ProjectionsContext projectionsContext;
     
    private final GroupByContext groupByContext;
     
    private final OrderByContext orderByContext;
     
    private final PaginationContext paginationContext;
     
    private final boolean containsSubquery;
}
 
    private boolean containsSubquery() {
        // FIXME process subquery
//        Collection<SubqueryPredicateSegment> subqueryPredicateSegments = getSqlStatement().findSQLSegments(SubqueryPredicateSegment.class);
//        for (SubqueryPredicateSegment each : subqueryPredicateSegments) {
//            if (!each.getAndPredicates().isEmpty()) {
//                return true;
//            }
//        }
        return false;
    }

public final class RouteResult {
     
    private final Collection<Collection<DataNode>> originalDataNodes = new LinkedList<>();
     
    private final Collection<RouteUnit> routeUnits = new LinkedHashSet<>();
}
 
public final class DataNode {
     
    private static final String DELIMITER = ".";
     
    private final String dataSourceName;
     
    private final String tableName;
}
 
public final class RouteUnit {
     
    private final RouteMapper dataSourceMapper;
     
    private final Collection<RouteMapper> tableMappers;
}
 
public final class RouteMapper {
     
    private final String logicName;
     
    private final String actualName;
}

org.apache.shardingsphere.sharding.route.engine.ShardingRouteDecorator#decorate#57
public RouteContext decorate(final RouteContext routeContext, final ShardingSphereMetaData metaData, final ShardingRule shardingRule, final ConfigurationProperties properties) {
        SQLStatementContext sqlStatementContext = routeContext.getSqlStatementContext();
        List<Object> parameters = routeContext.getParameters();
        //SQL校驗(yàn)  校驗(yàn)INSERT INTO .... ON DUPLICATE KEY UPDATE 和UPDATE語(yǔ)句中是否存在分片鍵
      ShardingStatementValidatorFactory.newInstance(
                sqlStatementContext.getSqlStatement()).ifPresent(validator -> validator.validate(shardingRule, sqlStatementContext.getSqlStatement(), parameters));
        //生成分片條件
        ShardingConditions shardingConditions = getShardingConditions(parameters, sqlStatementContext, metaData.getSchema(), shardingRule);
        //合并分片值
        boolean needMergeShardingValues = isNeedMergeShardingValues(sqlStatementContext, shardingRule);
        if (sqlStatementContext.getSqlStatement() instanceof DMLStatement && needMergeShardingValues) {
            checkSubqueryShardingValues(sqlStatementContext, shardingRule, shardingConditions);
            mergeShardingConditions(shardingConditions);
        }
        ShardingRouteEngine shardingRouteEngine = ShardingRouteEngineFactory.newInstance(shardingRule, metaData, sqlStatementContext, shardingConditions, properties);
        //得到路由結(jié)果
        RouteResult routeResult = shardingRouteEngine.route(shardingRule);
        if (needMergeShardingValues) {
            Preconditions.checkState(1 == routeResult.getRouteUnits().size(), "Must have one sharding with subquery.");
        }
        return new RouteContext(sqlStatementContext, parameters, routeResult);
    }

public final class ShardingConditions {
     
    private final List<ShardingCondition> conditions;
}
 
public class ShardingCondition {
     
    private final List<RouteValue> routeValues = new LinkedList<>();
}
 
 
public final class ListRouteValue<T extends Comparable<?>> implements RouteValue {
     
    private final String columnName;
     
    private final String tableName;
    //in或=條件對(duì)應(yīng)的值
    private final Collection<T> values;
     
    @Override
    public String toString() {
        return tableName + "." + columnName + (1 == values.size() ? " = " + new ArrayList<>(values).get(0) : " in (" + Joiner.on(",").join(values) + ")");
    }
}
 
public final class RangeRouteValue<T extends Comparable<?>> implements RouteValue {
     
    private final String columnName;
     
    private final String tableName;
    //between and 大于小于等范圍值的上下限
    private final Range<T> valueRange;
}

org.apache.shardingsphere.sharding.route.engine.ShardingRouteDecorator#isNeedMergeShardingValues#87
private boolean isNeedMergeShardingValues(final SQLStatementContext sqlStatementContext, final ShardingRule shardingRule) {
        return sqlStatementContext instanceof SelectStatementContext && ((SelectStatementContext) sqlStatementContext).isContainsSubquery()
                && !shardingRule.getShardingLogicTableNames(sqlStatementContext.getTablesContext().getTableNames()).isEmpty();
    }

org.apache.shardingsphere.core.strategy.route.inline.InlineShardingStrategy#doSharding
    public Collection<String> doSharding(final Collection<String> availableTargetNames, final Collection<RouteValue> shardingValues, final ConfigurationProperties properties) {
        RouteValue shardingValue = shardingValues.iterator().next();
        //ALLOW_RANGE_QUERY_WITH_INLINE_SHARDING設(shè)置為true，直接返回availableTargetNames，而不是根據(jù)RangeRouteValue計(jì)算
        if (properties.<Boolean>getValue(ConfigurationPropertyKey.ALLOW_RANGE_QUERY_WITH_INLINE_SHARDING) && shardingValue instanceof RangeRouteValue) {
            return availableTargetNames;
        }
        Preconditions.checkState(shardingValue instanceof ListRouteValue, "Inline strategy cannot support this type sharding:" + shardingValue.toString());
        Collection<String> shardingResult = doSharding((ListRouteValue) shardingValue);
        Collection<String> result = new TreeSet<>(String.CASE_INSENSITIVE_ORDER);
        for (String each : shardingResult) {
            if (availableTargetNames.contains(each)) {
                result.add(each);
            }
        }
        return result;
    }

org.apache.shardingsphere.masterslave.route.engine.MasterSlaveRouteDecorator#decorate    
    public RouteContext decorate(final RouteContext routeContext, final ShardingSphereMetaData metaData, final MasterSlaveRule masterSlaveRule, final ConfigurationProperties properties) {
        //為空證明沒(méi)有經(jīng)過(guò)分片路由
        if (routeContext.getRouteResult().getRouteUnits().isEmpty()) {
            //根據(jù)SQL判斷選擇走主庫(kù)還是從庫(kù)
            String dataSourceName = new MasterSlaveDataSourceRouter(masterSlaveRule).route(routeContext.getSqlStatementContext().getSqlStatement());
            RouteResult routeResult = new RouteResult();
           //根據(jù)具體的主庫(kù)/從庫(kù)名創(chuàng)建路由單元
            routeResult.getRouteUnits().add(new RouteUnit(new RouteMapper(dataSourceName, dataSourceName), Collections.emptyList()));
            return new RouteContext(routeContext.getSqlStatementContext(), Collections.emptyList(), routeResult);
        }
        Collection<RouteUnit> toBeRemoved = new LinkedList<>();
        Collection<RouteUnit> toBeAdded = new LinkedList<>();
        //不為空證明已經(jīng)被分片路由處理了
        for (RouteUnit each : routeContext.getRouteResult().getRouteUnits()) {
            if (masterSlaveRule.getName().equalsIgnoreCase(each.getDataSourceMapper().getActualName())) {
                //先標(biāo)記移除 因?yàn)檫@里是一組主從的名字而不是實(shí)際的庫(kù)
                toBeRemoved.add(each);
                //根據(jù)SQL判斷選擇走主庫(kù)還是從庫(kù)
                String actualDataSourceName = new MasterSlaveDataSourceRouter(masterSlaveRule).route(routeContext.getSqlStatementContext().getSqlStatement());
                //根據(jù)具體的主庫(kù)/從庫(kù)名創(chuàng)建路由單元
                toBeAdded.add(new RouteUnit(new RouteMapper(each.getDataSourceMapper().getLogicName(), actualDataSourceName), each.getTableMappers()));
            }
        }
        routeContext.getRouteResult().getRouteUnits().removeAll(toBeRemoved);
        routeContext.getRouteResult().getRouteUnits().addAll(toBeAdded);
        return routeContext;
    }

public final class MasterSlaveDataSourceRouter {
     
    private final MasterSlaveRule masterSlaveRule;
     
    /**
     * Route.
     *
     * @param sqlStatement SQL statement
     * @return data source name
     */
    public String route(final SQLStatement sqlStatement) {
        if (isMasterRoute(sqlStatement)) {
            MasterVisitedManager.setMasterVisited();
            return masterSlaveRule.getMasterDataSourceName();
        }
        return masterSlaveRule.getLoadBalanceAlgorithm().getDataSource(
                masterSlaveRule.getName(), masterSlaveRule.getMasterDataSourceName(), new ArrayList<>(masterSlaveRule.getSlaveDataSourceNames()));
    }
     
    private boolean isMasterRoute(final SQLStatement sqlStatement) {
        return containsLockSegment(sqlStatement) || !(sqlStatement instanceof SelectStatement) || MasterVisitedManager.isMasterVisited() || HintManager.isMasterRouteOnly();
    }
     
    private boolean containsLockSegment(final SQLStatement sqlStatement) {
        return sqlStatement instanceof SelectStatement && ((SelectStatement) sqlStatement).getLock().isPresent();
    }
}

public final class MasterVisitedManager {
     
    private static final ThreadLocal<Boolean> MASTER_VISITED = ThreadLocal.withInitial(() -> false);
     
    /**
     * Judge master data source visited in current thread.
     *
     * @return master data source visited or not in current thread
     */
    public static boolean isMasterVisited() {
        return MASTER_VISITED.get();
    }
     
    /**
     * Set master data source visited in current thread.
     */
    public static void setMasterVisited() {
        MASTER_VISITED.set(true);
    }
     
    /**
     * Clear master data source visited.
     */
    public static void clear() {
        MASTER_VISITED.remove();
    }
}

org.apache.shardingsphere.underlying.pluggble.prepare.BasePrepareEngine#executeRewrite
    private Collection<ExecutionUnit> executeRewrite(final String sql, final List<Object> parameters, final RouteContext routeContext) {
        //注冊(cè)重寫(xiě)裝飾器
        registerRewriteDecorator();
        //創(chuàng)建 SQLRewriteContext
        SQLRewriteContext sqlRewriteContext = rewriter.createSQLRewriteContext(sql, parameters, routeContext.getSqlStatementContext(), routeContext);
        //重寫(xiě)
        return routeContext.getRouteResult().getRouteUnits().isEmpty() ? rewrite(sqlRewriteContext) : rewrite(routeContext, sqlRewriteContext);
    }

@RequiredArgsConstructor
@Getter
@EqualsAndHashCode
@ToString
public final class ExecutionUnit {
     
    private final String dataSourceName;
     
    private final SQLUnit sqlUnit;
}
 
@AllArgsConstructor
@RequiredArgsConstructor
@Getter
@Setter
//根據(jù)sql判斷是否相等
@EqualsAndHashCode(of = { "sql" })
@ToString
public final class SQLUnit {
 
    private String sql;
 
    private final List<Object> parameters;
 
}

org.apache.shardingsphere.underlying.rewrite.SQLRewriteEntry#createSQLRewriteContext
    public SQLRewriteContext createSQLRewriteContext(final String sql, final List<Object> parameters, final SQLStatementContext sqlStatementContext, final RouteContext routeContext) {
        SQLRewriteContext result = new SQLRewriteContext(schemaMetaData, sqlStatementContext, sql, parameters);
        //sql參數(shù)重寫(xiě)
        decorate(decorators, result, routeContext);
        //生成SQLToken
        result.generateSQLTokens();
        return result;
    }
 
org.apache.shardingsphere.sharding.rewrite.context.ShardingSQLRewriteContextDecorator#decorate
    public void decorate(final ShardingRule shardingRule, final ConfigurationProperties properties, final SQLRewriteContext sqlRewriteContext) {
        for (ParameterRewriter each : new ShardingParameterRewriterBuilder(shardingRule, routeContext).getParameterRewriters(sqlRewriteContext.getSchemaMetaData())) {
            if (!sqlRewriteContext.getParameters().isEmpty() && each.isNeedRewrite(sqlRewriteContext.getSqlStatementContext())) {
                //參數(shù)重寫(xiě)
                each.rewrite(sqlRewriteContext.getParameterBuilder(), sqlRewriteContext.getSqlStatementContext(), sqlRewriteContext.getParameters());
            }
        }
        //sqlTokenGenerators
        sqlRewriteContext.addSQLTokenGenerators(new ShardingTokenGenerateBuilder(shardingRule, routeContext).getSQLTokenGenerators());
    }
 
org.apache.shardingsphere.underlying.rewrite.context.SQLRewriteContext#generateSQLTokens
    public void generateSQLTokens() {
        sqlTokens.addAll(sqlTokenGenerators.generateSQLTokens(sqlStatementContext, parameters, schemaMetaData));
    }

@RequiredArgsConstructor
@Getter
public abstract class SQLToken implements Comparable<SQLToken> {
     
    private final int startIndex;
     
    @Override
    public final int compareTo(final SQLToken sqlToken) {
        return startIndex - sqlToken.getStartIndex();
    }
}

org.apache.shardingsphere.underlying.rewrite.engine.SQLRouteRewriteEngine#rewrite
    public Map<RouteUnit, SQLRewriteResult> rewrite(final SQLRewriteContext sqlRewriteContext, final RouteResult routeResult) {
        Map<RouteUnit, SQLRewriteResult> result = new LinkedHashMap<>(routeResult.getRouteUnits().size(), 1);
        for (RouteUnit each : routeResult.getRouteUnits()) {
            //重寫(xiě)SQL+組裝參數(shù)
            result.put(each, new SQLRewriteResult(new RouteSQLBuilder(sqlRewriteContext, each).toSQL(), getParameters(sqlRewriteContext.getParameterBuilder(), routeResult, each)));
        }
        return result;
    }

org.apache.shardingsphere.underlying.rewrite.sql.impl.AbstractSQLBuilder#toSQL
    public final String toSQL() {
        if (context.getSqlTokens().isEmpty()) {
            return context.getSql();
        }
        Collections.sort(context.getSqlTokens());
        StringBuilder result = new StringBuilder();
        //截取第一個(gè)SQLToken之前的內(nèi)容  select * from
        result.append(context.getSql().substring(0, context.getSqlTokens().get(0).getStartIndex()));
        for (SQLToken each : context.getSqlTokens()) {
            //重寫(xiě)拼接每個(gè)SQLToken對(duì)應(yīng)的內(nèi)容  t_order ->t_order_0
            result.append(getSQLTokenText(each));
            //拼接SQLToken中間不變的內(nèi)容 where created_by = '123'
            result.append(getConjunctionText(each));
        }
        return result.toString();
    }

org.apache.shardingsphere.underlying.rewrite.engine.SQLRouteRewriteEngine#getParameters
    private List<Object> getParameters(final ParameterBuilder parameterBuilder, final RouteResult routeResult, final RouteUnit routeUnit) {
        if (parameterBuilder instanceof StandardParameterBuilder || routeResult.getOriginalDataNodes().isEmpty() || parameterBuilder.getParameters().isEmpty()) {
            //非插入語(yǔ)句直接返回
            return parameterBuilder.getParameters();
        }
        List<Object> result = new LinkedList<>();
        int count = 0;
        for (Collection<DataNode> each : routeResult.getOriginalDataNodes()) {
            if (isInSameDataNode(each, routeUnit)) {
                //插入語(yǔ)句參數(shù)分組構(gòu)造
                result.addAll(((GroupedParameterBuilder) parameterBuilder).getParameters(count));
            }
            count++;
        }
        return result;
    }

org.apache.shardingsphere.sharding.execute.sql.prepare.SQLExecutePrepareTemplate#getSynchronizedExecuteUnitGroups
    private Collection<InputGroup<StatementExecuteUnit>> getSynchronizedExecuteUnitGroups(
            final Collection<ExecutionUnit> executionUnits, final SQLExecutePrepareCallback callback) throws SQLException {
        //根據(jù)數(shù)據(jù)源將SQLUnit分組 key=dataSourceName
        Map<String, List<SQLUnit>> sqlUnitGroups = getSQLUnitGroups(executionUnits);
        Collection<InputGroup<StatementExecuteUnit>> result = new LinkedList<>();
        //創(chuàng)建sql執(zhí)行組
        for (Entry<String, List<SQLUnit>> entry : sqlUnitGroups.entrySet()) {
            result.addAll(getSQLExecuteGroups(entry.getKey(), entry.getValue(), callback));
        }
        return result;
    }
 
org.apache.shardingsphere.sharding.execute.sql.prepare.SQLExecutePrepareTemplate#getSQLExecuteGroups
    private List<InputGroup<StatementExecuteUnit>> getSQLExecuteGroups(final String dataSourceName,
                                                                       final List<SQLUnit> sqlUnits, final SQLExecutePrepareCallback callback) throws SQLException {
        List<InputGroup<StatementExecuteUnit>> result = new LinkedList<>();
        //每個(gè)連接需要執(zhí)行的最大sql數(shù)量
        int desiredPartitionSize = Math.max(0 == sqlUnits.size() % maxConnectionsSizePerQuery ? sqlUnits.size() / maxConnectionsSizePerQuery : sqlUnits.size() / maxConnectionsSizePerQuery + 1, 1);
        //分組，每組對(duì)應(yīng)一條數(shù)據(jù)庫(kù)連接
        List<List<SQLUnit>> sqlUnitPartitions = Lists.partition(sqlUnits, desiredPartitionSize);
        //選擇連接模式 連接限制/內(nèi)存限制
        ConnectionMode connectionMode = maxConnectionsSizePerQuery < sqlUnits.size() ? ConnectionMode.CONNECTION_STRICTLY : ConnectionMode.MEMORY_STRICTLY;
        //創(chuàng)建連接
        List<Connection> connections = callback.getConnections(connectionMode, dataSourceName, sqlUnitPartitions.size());
        int count = 0;
        for (List<SQLUnit> each : sqlUnitPartitions) {
            //綁定連接和SQLUnit 創(chuàng)建StatementExecuteUnit
            result.add(getSQLExecuteGroup(connectionMode, connections.get(count++), dataSourceName, each, callback));
        }
        return result;
    }

private List<Connection> createConnections(final String dataSourceName, final ConnectionMode connectionMode, final DataSource dataSource, final int connectionSize) throws SQLException {
    if (1 == connectionSize) {
        Connection connection = createConnection(dataSourceName, dataSource);
        replayMethodsInvocation(connection);
        return Collections.singletonList(connection);
    }
    if (ConnectionMode.CONNECTION_STRICTLY == connectionMode) {
        return createConnections(dataSourceName, dataSource, connectionSize);
    }
    //內(nèi)存限制模式加鎖 一次性獲取所有的連接
    synchronized (dataSource) {
        return createConnections(dataSourceName, dataSource, connectionSize);
    }
}

org.apache.shardingsphere.shardingjdbc.executor.PreparedStatementExecutor#executeQuery#101 
  org.apache.shardingsphere.shardingjdbc.executor.PreparedStatementExecutor#getQueryResult
    private QueryResult getQueryResult(final Statement statement, final ConnectionMode connectionMode) throws SQLException {
        PreparedStatement preparedStatement = (PreparedStatement) statement;
        ResultSet resultSet = preparedStatement.executeQuery();
        getResultSets().add(resultSet);
        //executeQuery 中根據(jù)連接模式選擇流式/內(nèi)存
        return ConnectionMode.MEMORY_STRICTLY == connectionMode ? new StreamQueryResult(resultSet) : new MemoryQueryResult(resultSet);
    }
 
//execute 單獨(dú)調(diào)用getResultSet中只會(huì)使用流式合并
org.apache.shardingsphere.shardingjdbc.jdbc.core.statement.ShardingPreparedStatement#getResultSet#158
  org.apache.shardingsphere.shardingjdbc.jdbc.core.statement.ShardingPreparedStatement#getQueryResults 
    private List<QueryResult> getQueryResults(final List<ResultSet> resultSets) throws SQLException {
        List<QueryResult> result = new ArrayList<>(resultSets.size());
        for (ResultSet each : resultSets) {
            if (null != each) {
                result.add(new StreamQueryResult(each));
            }
        }
        return result;
    }

public boolean isHoldTransaction() {
        return (TransactionType.LOCAL == transactionType && !getAutoCommit()) || (TransactionType.XA == transactionType && isInShardingTransaction());
    }

org.apache.shardingsphere.shardingjdbc.jdbc.core.statement.ShardingPreparedStatement#mergeQuery#190
 org.apache.shardingsphere.underlying.pluggble.merge.MergeEngine#merge#61
    org.apache.shardingsphere.underlying.merge.MergeEntry#process
    public MergedResult process(final List<QueryResult> queryResults, final SQLStatementContext sqlStatementContext) throws SQLException {
        //分片合并
        Optional<MergedResult> mergedResult = merge(queryResults, sqlStatementContext);
        //脫敏處理
        Optional<MergedResult> result = mergedResult.isPresent() ? Optional.of(decorate(mergedResult.get(), sqlStatementContext)) : decorate(queryResults.get(0), sqlStatementContext);
        //只有讀寫(xiě)分離的情況下，orElseGet會(huì)不存在，TransparentMergedResult
        return result.orElseGet(() -> new TransparentMergedResult(queryResults.get(0)));
    }

@RequiredArgsConstructor
public final class TransparentMergedResult implements MergedResult {
     
    private final QueryResult queryResult;
     
    @Override
    public boolean next() throws SQLException {
        return queryResult.next();
    }
     
    @Override
    public Object getValue(final int columnIndex, final Class<?> type) throws SQLException {
        return queryResult.getValue(columnIndex, type);
    }
     
    @Override
    public Object getCalendarValue(final int columnIndex, final Class<?> type, final Calendar calendar) throws SQLException {
        return queryResult.getCalendarValue(columnIndex, type, calendar);
    }
     
    @Override
    public InputStream getInputStream(final int columnIndex, final String type) throws SQLException {
        return queryResult.getInputStream(columnIndex, type);
    }
     
    @Override
    public boolean wasNull() throws SQLException {
        return queryResult.wasNull();
    }
}

org.apache.shardingsphere.underlying.merge.MergeEntry#merge
    private Optional<MergedResult> merge(final List<QueryResult> queryResults, final SQLStatementContext sqlStatementContext) throws SQLException {
        for (Entry<BaseRule, ResultProcessEngine> entry : engines.entrySet()) {
            if (entry.getValue() instanceof ResultMergerEngine) {
                //選擇不同類(lèi)型的 resultMerger
                ResultMerger resultMerger = ((ResultMergerEngine) entry.getValue()).newInstance(databaseType, entry.getKey(), properties, sqlStatementContext);
                //歸并
                return Optional.of(resultMerger.merge(queryResults, sqlStatementContext, schemaMetaData));
            }
        }
        return Optional.empty();
    }
 
org.apache.shardingsphere.sharding.merge.ShardingResultMergerEngine#newInstance
    public ResultMerger newInstance(final DatabaseType databaseType, final ShardingRule shardingRule, final ConfigurationProperties properties, final SQLStatementContext sqlStatementContext) {
        if (sqlStatementContext instanceof SelectStatementContext) {
            return new ShardingDQLResultMerger(databaseType);
        }
        if (sqlStatementContext.getSqlStatement() instanceof DALStatement) {
            return new ShardingDALResultMerger(shardingRule);
        }
        return new TransparentResultMerger();
    }

org.apache.shardingsphere.sharding.merge.dql.ShardingDQLResultMerger#merge
    public MergedResult merge(final List<QueryResult> queryResults, final SQLStatementContext sqlStatementContext, final SchemaMetaData schemaMetaData) throws SQLException {
        if (1 == queryResults.size()) {
            return new IteratorStreamMergedResult(queryResults);
        }
        Map<String, Integer> columnLabelIndexMap = getColumnLabelIndexMap(queryResults.get(0));
        SelectStatementContext selectStatementContext = (SelectStatementContext) sqlStatementContext;
        selectStatementContext.setIndexes(columnLabelIndexMap);
        //分組聚合，排序，遍歷
        MergedResult mergedResult = build(queryResults, selectStatementContext, columnLabelIndexMap, schemaMetaData);
        //分頁(yè)歸并
        return decorate(queryResults, selectStatementContext, mergedResult);
    }
 
org.apache.shardingsphere.sharding.merge.dql.ShardingDQLResultMerger#build
    private MergedResult build(final List<QueryResult> queryResults, final SelectStatementContext selectStatementContext,
                               final Map<String, Integer> columnLabelIndexMap, final SchemaMetaData schemaMetaData) throws SQLException {
        if (isNeedProcessGroupBy(selectStatementContext)) {
            //分組聚合歸并
            return getGroupByMergedResult(queryResults, selectStatementContext, columnLabelIndexMap, schemaMetaData);
        }
        if (isNeedProcessDistinctRow(selectStatementContext)) {
            setGroupByForDistinctRow(selectStatementContext);
            //分組聚合歸并
            return getGroupByMergedResult(queryResults, selectStatementContext, columnLabelIndexMap, schemaMetaData);
        }
        if (isNeedProcessOrderBy(selectStatementContext)) {
            //排序歸并
            return new OrderByStreamMergedResult(queryResults, selectStatementContext, schemaMetaData);
        }
        //遍歷歸并
        return new IteratorStreamMergedResult(queryResults);
    }
 
org.apache.shardingsphere.sharding.merge.dql.ShardingDQLResultMerger#decorate
    private MergedResult decorate(final List<QueryResult> queryResults, final SelectStatementContext selectStatementContext, final MergedResult mergedResult) throws SQLException {
        PaginationContext paginationContext = selectStatementContext.getPaginationContext();
        if (!paginationContext.isHasPagination() || 1 == queryResults.size()) {
            return mergedResult;
        }
        String trunkDatabaseName = DatabaseTypes.getTrunkDatabaseType(databaseType.getName()).getName();
        //根據(jù)數(shù)據(jù)庫(kù)類(lèi)型分頁(yè)歸并
        if ("MySQL".equals(trunkDatabaseName) || "PostgreSQL".equals(trunkDatabaseName)) {
            return new LimitDecoratorMergedResult(mergedResult, paginationContext);
        }
        if ("Oracle".equals(trunkDatabaseName)) {
            return new RowNumberDecoratorMergedResult(mergedResult, paginationContext);
        }
        if ("SQLServer".equals(trunkDatabaseName)) {
            return new TopAndRowNumberDecoratorMergedResult(mergedResult, paginationContext);
        }
        return mergedResult;
    }

public class ExecutionContext {
 
    private final SQLStatementContext sqlStatementContext;
 
    private final Collection<ExecutionUnit> executionUnits = new LinkedHashSet<>();
}
 
public final class ExecutionUnit {
     
    private final String dataSourceName;
     
    private final SQLUnit sqlUnit;
}
 
public final class SQLUnit {
 
    private String sql;
 
    private final List<Object> parameters;
 
}

public final class RuleContextManager {
 
    private static final ThreadLocal<RuleContextManager> SKIP_CONTEXT_HOLDER = ThreadLocal.withInitial(RuleContextManager::new);
 
    /**
     * 是否跳過(guò)sharding
     */
    private boolean skipSharding;
 
    /**
     * 是否路由至主庫(kù)
     */
    private boolean masterRoute;
 
    public static boolean isSkipSharding() {
        return SKIP_CONTEXT_HOLDER.get().skipSharding;
    }
 
    public static void setSkipSharding(boolean skipSharding) {
        SKIP_CONTEXT_HOLDER.get().skipSharding = skipSharding;
    }
 
    public static boolean isMasterRoute() {
 
        return SKIP_CONTEXT_HOLDER.get().masterRoute;
    }
 
    public static void setMasterRoute(boolean masterRoute) {
        SKIP_CONTEXT_HOLDER.get().masterRoute = masterRoute;
    }
 
    public static void clear(){
        SKIP_CONTEXT_HOLDER.remove();
    }
 
}

org.apache.shardingsphere.underlying.pluggble.prepare.BasePrepareEngine#buildSkipContext
// 判斷是否可以跳過(guò)sharding,構(gòu)造RuleContextManager的值
private void buildSkipContext(final String sql){
    Set<String> sqlTokenSet = new HashSet<>(Arrays.asList(sql.split("[\\s]")));
        if (CollectionUtils.isNotEmpty(rules)) {
            for (BaseRule baseRule : rules) {
                //定制方法，ShardingRule實(shí)現(xiàn)，判斷sqlTokenSet是否包含邏輯表即可
                if(baseRule.hasContainShardingTable(sqlTokenSet)){
                    RuleContextManager.setSkipSharding(false);
                    break;
                }else {
                    RuleContextManager.setSkipSharding(true);
                }
            }
        }
}
 
org.apache.shardingsphere.core.rule.ShardingRule#hasContainShardingTable
public Boolean hasContainShardingTable(Set<String> sqlTokenSet) {
      //logicTableNameList通過(guò)遍歷TableRule可以得到
       for (String logicTable : logicTableNameList) {
            if (sqlTokenSet.contains(logicTable)) {
                return true;
            }
        }
        return false;
    }

public class SkipShardingStatement implements SQLStatement{
    @Override
    public int getParameterCount() {
        return 0;
    }
}
 
org.apache.shardingsphere.sql.parser.SQLParserEngine#parse0
    private SQLStatement parse0(final String sql, final boolean useCache) {
        if (useCache) {
            Optional<SQLStatement> cachedSQLStatement = cache.getSQLStatement(sql);
            if (cachedSQLStatement.isPresent()) {
                return cachedSQLStatement.get();
            }
        }
        ParseTree parseTree = new SQLParserExecutor(databaseTypeName, sql).execute().getRootNode();
        /**
         * 跳過(guò)sharding 需要判斷是否需要路由至主庫(kù) 如果不是select語(yǔ)句直接跳過(guò)
         * 是select語(yǔ)句則需要通過(guò)繼續(xù)解析判斷是否有鎖
         */
        SQLStatement result ;
        if(RuleContextManager.isSkipSharding()&&!VisitorRule.SELECT.equals(VisitorRule.valueOf(parseTree.getClass()))){
            RuleContextManager.setMasterRoute(true);
            result = new SkipShardingStatement();
        }else {
            result = (SQLStatement) ParseTreeVisitorFactory.newInstance(databaseTypeName, VisitorRule.valueOf(parseTree.getClass())).visit(parseTree);
        }
        if (useCache) {
            cache.put(sql, result);
        }
        return result;
    }
 
org.apache.shardingsphere.sql.parser.mysql.visitor.impl.MySQLDMLVisitor#visitSelectClause
    public ASTNode visitSelectClause(final SelectClauseContext ctx) {
        SelectStatement result = new SelectStatement();
        // 跳過(guò)sharding 只需要判斷是否有鎖來(lái)決定是否路由至主庫(kù)即可
        if(RuleContextManager.isSkipSharding()){
            if (null != ctx.lockClause()) {
                result.setLock((LockSegment) visit(ctx.lockClause()));
                RuleContextManager.setMasterRoute(true);
            }
            return result;
        }
        //...后續(xù)解析
    }
 
org.apache.shardingsphere.underlying.route.DataNodeRouter#createRouteContext
    private RouteContext createRouteContext(final String sql, final List<Object> parameters, final boolean useCache) {
        SQLStatement sqlStatement = parserEngine.parse(sql, useCache);
        //如果需要跳過(guò)sharding 不進(jìn)行后續(xù)的解析直接返回
        if (RuleContextManager.isSkipSharding()) {
            return new RouteContext(sqlStatement, parameters, new RouteResult());
        }
        //...解析
    }
 
org.apache.shardingsphere.sharding.route.engine.ShardingRouteDecorator#decorate
    public RouteContext decorate(final RouteContext routeContext, final ShardingSphereMetaData metaData, final ShardingRule shardingRule, final ConfigurationProperties properties) {
        // 跳過(guò)sharding路由
        if(RuleContextManager.isSkipSharding()){
            return routeContext;
        }
        //...路由
    ｝

public ExecutionContext prepare(final String sql, final List<Object> parameters) {
    List<Object> clonedParameters = cloneParameters(parameters);
    // 判斷是否可以跳過(guò)sharding,構(gòu)造RuleContextManager的值
    buildSkipContext(sql);  
    RouteContext routeContext = executeRoute(sql, clonedParameters);
    ExecutionContext result = new ExecutionContext(routeContext.getSqlStatementContext());
    // 跳過(guò)sharding的sql最后的路由結(jié)果一定只有一個(gè)庫(kù)
    if(RuleContextManager.isSkipSharding()){
        log.debug("可以跳過(guò)sharding的場(chǎng)景 {}", sql);
        if(!Objects.isNull(routeContext.getRouteResult())){
            Collection<String> allInstanceDataSourceNames = this.metaData.getDataSources().getAllInstanceDataSourceNames();
            int routeUnitsSize = routeContext.getRouteResult().getRouteUnits().size();
            /*
             * 1. 沒(méi)有讀寫(xiě)分離的情況下  跳過(guò)sharding路由會(huì)導(dǎo)致routeUnitsSize為0 此時(shí)需要判斷數(shù)據(jù)源數(shù)量是否為1
             * 2. 讀寫(xiě)分離情況下 只會(huì)路由至具體的主庫(kù)或從庫(kù) routeUnitsSize數(shù)量應(yīng)該為1
             */
            if(!(routeUnitsSize == 0 && allInstanceDataSourceNames.size()==1)|| routeUnitsSize>1){
                throw new ShardingSphereException("可以跳過(guò)sharding,但是路由結(jié)果不唯一,SQL= %s ,routeUnits= %s ",sql, routeContext.getRouteResult().getRouteUnits());
            }
            Collection<String> actualDataSourceNames = routeContext.getRouteResult().getActualDataSourceNames();
            // 手動(dòng)創(chuàng)建執(zhí)行單元
            String datasourceName = CollectionUtils.isEmpty(actualDataSourceNames)? allInstanceDataSourceNames.iterator().next():actualDataSourceNames.iterator().next();
            ExecutionUnit executionUnit = new ExecutionUnit(datasourceName, new SQLUnit(sql, clonedParameters));
            result.getExecutionUnits().add(executionUnit);
            //標(biāo)記該結(jié)果需要跳過(guò)
            result.setSkipShardingScenarioFlag(true);
        }
    }else {
        result.getExecutionUnits().addAll(executeRewrite(sql, clonedParameters, routeContext));
    }
    if (properties.<Boolean>getValue(ConfigurationPropertyKey.SQL_SHOW)) {
        SQLLogger.logSQL(sql, properties.<Boolean>getValue(ConfigurationPropertyKey.SQL_SIMPLE), result.getSqlStatementContext(), result.getExecutionUnits());
    }
    return result;
}

org.apache.shardingsphere.shardingjdbc.jdbc.core.statement.ShardingPreparedStatement#executeQuery
    public ResultSet executeQuery() throws SQLException {
        ResultSet result;
        try {
            clearPrevious();
            prepare();
            initPreparedStatementExecutor();
            List<QueryResult> queryResults = preparedStatementExecutor.executeQuery();
            List<ResultSet> resultSets = preparedStatementExecutor.getResultSets();
        // 定制開(kāi)發(fā)，不分片跳過(guò)合并
            if(executionContext.isSkipShardingScenarioFlag()){
                return CollectionUtils.isNotEmpty(resultSets) ? resultSets.get(0) : null;
            }
            MergedResult mergedResult = mergeQuery(queryResults);
            result = new ShardingResultSet(resultSets, mergedResult, this, executionContext);
        } finally {
            clearBatch();
        }
        currentResultSet = result;
        return result;
    }
org.apache.shardingsphere.shardingjdbc.jdbc.core.statement.ShardingPreparedStatement#getResultSet
    public ResultSet getResultSet() throws SQLException {
        if (null != currentResultSet) {
            return currentResultSet;
        }
        List<ResultSet> resultSets = getResultSets();
        // 定制開(kāi)發(fā)，不分片跳過(guò)合并
        if(executionContext.isSkipShardingScenarioFlag()){
            return CollectionUtils.isNotEmpty(resultSets) ? resultSets.get(0) : null;
        }
 
        if (executionContext.getSqlStatementContext() instanceof SelectStatementContext || executionContext.getSqlStatementContext().getSqlStatement() instanceof DALStatement) {
            MergedResult mergedResult = mergeQuery(getQueryResults(resultSets));
            currentResultSet = new ShardingResultSet(resultSets, mergedResult, this, executionContext);
        }
        return currentResultSet;
    }
org.apache.shardingsphere.shardingjdbc.jdbc.core.statement.ShardingPreparedStatement#isAccumulate
    public boolean isAccumulate() {
        //定制開(kāi)發(fā)，不分片跳過(guò)計(jì)算
        if(executionContext.isSkipShardingScenarioFlag()){
            return false;
        }
        return !connection.getRuntimeContext().getRule().isAllBroadcastTables(executionContext.getSqlStatementContext().getTablesContext().getTableNames());
    }

org.apache.shardingsphere.shardingjdbc.jdbc.adapter.AbstractConnectionAdapter#close
public final void close() throws SQLException {
        closed = true;
        MasterVisitedManager.clear();
        TransactionTypeHolder.clear();
        RuleContextManager.clear();
        int connectionSize = cachedConnections.size();
        try {
            forceExecuteTemplateForClose.execute(cachedConnections.entries(), cachedConnections -> cachedConnections.getValue().close());
        } finally {
            cachedConnections.clear();
            rootInvokeHook.finish(connectionSize);
        }
    }

org.apache.shardingsphere.masterslave.route.engine.MasterSlaveRouteDecorator#decorate
    public RouteContext decorate(final RouteContext routeContext, final ShardingSphereMetaData metaData, final MasterSlaveRule masterSlaveRule, final ConfigurationProperties properties) {
        /**
         * 如果配置了強(qiáng)制主庫(kù) MasterVisitedManager設(shè)置為true
         * 后續(xù)isMasterRoute中會(huì)保證路由至主庫(kù)
         */
        if(properties.<Boolean>getValue(ConfigurationPropertyKey.MASTER_ROUTE_ONLY)){
            MasterVisitedManager.setMasterVisited();
        }
        //...路由邏輯
        return routeContext;
    }

org.apache.shardingsphere.masterslave.route.engine.impl.MasterSlaveDataSourceRouter#isMasterRoute
    private boolean isMasterRoute(final SQLStatement sqlStatement) {
        if(sqlStatement instanceof SkipShardingStatement){
            // 優(yōu)先以MasterVisitedManager中的值為準(zhǔn)
            return MasterVisitedManager.isMasterVisited()|| RuleContextManager.isMasterRoute();
        }
        return containsLockSegment(sqlStatement) || !(sqlStatement instanceof SelectStatement) || MasterVisitedManager.isMasterVisited() || HintManager.isMasterRouteOnly();
    }

org.apache.shardingsphere.underlying.pluggble.prepare.BasePrepareEngine#prepare
    /**
     * Prepare to execute.
     *
     * @param sql SQL
     * @param parameters SQL parameters
     * @return execution context
     */
    public ExecutionContext prepare(final String sql, final List<Object> parameters) {
        List<Object> clonedParameters = cloneParameters(parameters);
        RouteContext routeContext = executeRoute(sql, clonedParameters);
        ExecutionContext result = new ExecutionContext(routeContext.getSqlStatementContext());
        result.getExecutionUnits().addAll(executeRewrite(sql, clonedParameters, routeContext));
        //sql打印
        if (properties.<Boolean>getValue(ConfigurationPropertyKey.SQL_SHOW)) {
            SQLLogger.logSQL(sql, properties.<Boolean>getValue(ConfigurationPropertyKey.SQL_SIMPLE), result.getSqlStatementContext(), result.getExecutionUnits());
        }
        return result;
    }

public abstract class TypedProperties<E extends Enum & TypedPropertyKey> {
     
    private static final String LINE_SEPARATOR = System.getProperty("line.separator");
     
    @Getter
    private final Properties props;
     
    private final Map<E, TypedPropertyValue> cache;
     
    public TypedProperties(final Class<E> keyClass, final Properties props) {
        this.props = props;
        cache = preload(keyClass);
    }
     
    private Map<E, TypedPropertyValue> preload(final Class<E> keyClass) {
        E[] enumConstants = keyClass.getEnumConstants();
        Map<E, TypedPropertyValue> result = new HashMap<>(enumConstants.length, 1);
        Collection<String> errorMessages = new LinkedList<>();
        for (E each : enumConstants) {
            TypedPropertyValue value = null;
            try {
                value = new TypedPropertyValue(each, props.getOrDefault(each.getKey(), each.getDefaultValue()).toString());
            } catch (final TypedPropertyValueException ex) {
                errorMessages.add(ex.getMessage());
            }
            result.put(each, value);
        }
        if (!errorMessages.isEmpty()) {
            throw new ShardingSphereConfigurationException(Joiner.on(LINE_SEPARATOR).join(errorMessages));
        }
        return result;
    }
     
    /**
     * Get property value.
     *
     * @param key property key
     * @param <T> class type of return value
     * @return property value
     */
    @SuppressWarnings("unchecked")
    public <T> T getValue(final E key) {
        return (T) cache.get(key).getValue();
    }
 
    /**
     * vivo定制改造方法 refresh property value.
     * @param key property key
     * @param value property value
     * @return 更新配置是否成功
     */
    public boolean refreshValue(String key, String value){
        //獲取配置類(lèi)支持的配置項(xiàng)
        E[] enumConstants = targetKeyClass.getEnumConstants();
        for (E each : enumConstants) {
            //遍歷新的值
            if(each.getKey().equals(key)){
                try {
                    //空白value認(rèn)為無(wú)效,取默認(rèn)值
                    if(!StringUtils.isBlank(value)){
                        value = each.getDefaultValue();
                    }
                    //構(gòu)造新屬性
                    TypedPropertyValue typedPropertyValue = new TypedPropertyValue(each, value);
                    //替換緩存
                    cache.put(each, typedPropertyValue);
                    //原始屬性也替換下,有可能會(huì)通過(guò)RuntimeContext直接獲取Properties
                    props.put(key,value);
                    return true;
                } catch (final TypedPropertyValueException ex) {
                    log.error("refreshValue error. key={} , value={}", key, value, ex);
                }
            }
        }
        return false;
    }
}

<update id="batchUpdate">
        <foreach collectinotallow="orderList" item="item">
               update t_order set
               status = 1,
               updated_by = #{item.updatedBy}
               WHERE created_by = #{item.createdBy};
        </foreach>
    </update>

org.apache.shardingsphere.underlying.pluggble.prepare.BasePrepareEngine#prepareBatch
   private ExecutionContext prepareBatch(List<String> splitSqlList, final List<Object> allParameters) {
       //SQL去重
       List<String> sqlList = splitSqlList.stream().distinct().collect(Collectors.toList());
       if (sqlList.size() > 1) {
           throw new ShardingSphereException("不支持多條SQL,請(qǐng)檢查SQL," + sqlList.toString());
       }
       //以第一條SQL為標(biāo)準(zhǔn)
       String sql = sqlList.get(0);
       //所有的執(zhí)行單元
       Collection<ExecutionUnit> globalExecutionUnitList = new ArrayList<>();
       //初始化最后的執(zhí)行結(jié)果
       ExecutionContext executionContextResult = null;
       //根據(jù)所有參數(shù)數(shù)量和SQL語(yǔ)句數(shù)量 計(jì)算每組參數(shù)的數(shù)量
       int eachSqlParameterCount = allParameters.size() / splitSqlList.size();
       //平均分配每條SQL的參數(shù)
       List<List<Object>> eachSqlParameterListList = Lists.partition(allParameters, eachSqlParameterCount);
       for (List<Object> eachSqlParameterList : eachSqlParameterListList) {
           //每條SQL參數(shù)不同 需要根據(jù)參數(shù)路由不同的結(jié)果  實(shí)際的SqlStatementContext 是一致的
           RouteContext routeContext = executeRoute(sql, eachSqlParameterList);
           //由于SQL一樣  實(shí)際的SqlStatementContext 是一致的 只需初始化一次
           if (executionContextResult == null) {
               executionContextResult = new ExecutionContext(routeContext.getSqlStatementContext());
           }
           globalExecutionUnitList.addAll(executeRewrite(sql, eachSqlParameterList, routeContext));
       }
       //排序打印日志
       executionContextResult.getExtendMap().put(EXECUTION_UNIT_LIST, globalExecutionUnitList.stream().sorted(Comparator.comparing(ExecutionUnit::getDataSourceName)).collect(Collectors.toList()));
       if (properties.<Boolean>getValue(ConfigurationPropertyKey.SQL_SHOW)) {
           SQLLogger.logSQL(sql, properties.<Boolean>getValue(ConfigurationPropertyKey.SQL_SIMPLE),
                   executionContextResult.getSqlStatementContext(), (Collection<ExecutionUnit>) executionContextResult.getExtendMap().get(EXECUTION_UNIT_LIST));
       }
       return executionContextResult;
   }

@RequiredArgsConstructor
@Getter
public class ExecutionContext {
 
    private final SQLStatementContext sqlStatementContext;
 
    private final Collection<ExecutionUnit> executionUnits = new LinkedHashSet<>();
 
    /**
     * 自定義擴(kuò)展變量
     */
    private final Map<ExtendEnum,Object> extendMap = new HashMap<>();
 
    /**
     * 定制擴(kuò)展，是否可以跳過(guò)分片邏輯
     */
    @Setter
    private boolean skipShardingScenarioFlag = false;
}
 
@RequiredArgsConstructor
@Getter
@EqualsAndHashCode
@ToString
public final class ExecutionUnit {
     
    private final String dataSourceName;
     
    private final SQLUnit sqlUnit;
}
 
@AllArgsConstructor
@RequiredArgsConstructor
@Getter
@Setter
//根據(jù)SQL判斷是否相等
@EqualsAndHashCode(of = { "sql" })
@ToString
public final class SQLUnit {
 
    private String sql;
 
    private final List<Object> parameters;
 
}

org.apache.shardingsphere.shardingjdbc.executor.PreparedStatementExecutor#init
    public void init(final ExecutionContext executionContext) throws SQLException {
        setSqlStatementContext(executionContext.getSqlStatementContext());
        //兼容批量update 分庫(kù)分表后同一張表的情況 判斷是否存在EXECUTION_UNIT_LIST 存在則使用未去重的List進(jìn)行后續(xù)的操作
        if (MapUtils.isNotEmpty(executionContext.getExtendMap())){
            Collection<ExecutionUnit> executionUnitCollection = (Collection<ExecutionUnit>) executionContext.getExtendMap().get(EXECUTION_UNIT_LIST);
            if(CollectionUtils.isNotEmpty(executionUnitCollection)){
                getInputGroups().addAll(obtainExecuteGroups(executionUnitCollection));
            }
        }else {
            getInputGroups().addAll(obtainExecuteGroups(executionContext.getExecutionUnits()));
        }
        cacheStatements();
    }

org.apache.shardingsphere.sharding.route.engine.condition.engine.WhereClauseShardingConditionEngine#createShardingConditions
    private Collection<ShardingCondition> createShardingConditions(final SQLStatementContext sqlStatementContext, final Collection<AndPredicate> andPredicates, final List<Object> parameters) {
        Collection<ShardingCondition> result = new LinkedList<>();
        for (AndPredicate each : andPredicates) {
            Map<Column, Collection<RouteValue>> routeValueMap = createRouteValueMap(sqlStatementContext, each, parameters);
            if (routeValueMap.isEmpty()) {
                return Collections.emptyList();
            }
            result.add(createShardingCondition(routeValueMap));
        }
        //去重
        Collection<ShardingCondition> distinctResult = result.stream().distinct().collect(Collectors.toCollection(LinkedList::new));
        return distinctResult;
    }

org.apache.shardingsphere.sharding.route.engine.ShardingRouteDecorator#decorate
public RouteContext decorate(final RouteContext routeContext, final ShardingSphereMetaData metaData, final ShardingRule shardingRule, final ConfigurationProperties properties) {
        //省略...
        //獲取 ShardingConditions
        ShardingConditions shardingConditions = getShardingConditions(parameters, sqlStatementContext, metaData.getSchema(), shardingRule);
        boolean hintAlgorithm = isHintAlgorithm(sqlStatementContext, shardingRule);
        //判斷是否允許全路由
        if (!properties.<Boolean>getValue(ConfigurationPropertyKey.ALLOW_EMPTY_SHARDING_CONDITIONS)) {
            //如果不是Hint算法
            if(!isHintAlgorithm(sqlStatementContext, shardingRule)){
                /** 如果是DML語(yǔ)句  則可能有兩種情況 這兩種情況是根據(jù)getShardingConditions方法的內(nèi)部邏輯而來(lái)的
                 *  一種是非插入語(yǔ)句  shardingConditions.getConditions()為空即可
                 *  一種是插入語(yǔ)句 插入語(yǔ)句shardingConditions.getConditions()不會(huì)為空  但是ShardingCondition的routeValues是空的
                 */
                if (sqlStatementContext.getSqlStatement() instanceof DMLStatement) {
                    if(shardingConditions.getConditions().isEmpty()) {
                        throw new ShardingSphereException("SQL不包含分庫(kù)分表鍵,請(qǐng)檢查SQL");
                    }else {
                        if (sqlStatementContext instanceof InsertStatementContext) {
                            List<ShardingCondition> routeValuesNotEmpty = shardingConditions.getConditions().stream().filter(r -> CollectionUtils.isNotEmpty(r.getRouteValues())).collect(Collectors.toList());
                            if(CollectionUtils.isEmpty(routeValuesNotEmpty)){
                                throw new ShardingSphereException("SQL不包含分庫(kù)分表鍵,請(qǐng)檢查SQL");
                            }
                        }
                    }
                }
            }
        }
        boolean needMergeShardingValues = isNeedMergeShardingValues(sqlStatementContext, shardingRule);
        //省略...
        return new RouteContext(sqlStatementContext, parameters, routeResult);
    }
 
private boolean isHintAlgorithm(final SQLStatementContext sqlStatementContext, final ShardingRule shardingRule) {
        // 場(chǎng)景a 全局默認(rèn)策略是否使用強(qiáng)制路由策略
        if(shardingRule.getDefaultDatabaseShardingStrategy() instanceof HintShardingStrategy
                || shardingRule.getDefaultTableShardingStrategy() instanceof HintShardingStrategy){
            return true;
        }
        for (String each : sqlStatementContext.getTablesContext().getTableNames()) {
            Optional<TableRule> tableRule = shardingRule.findTableRule(each);
            //場(chǎng)景b 指定表是否使用強(qiáng)制路由策略
            if (tableRule.isPresent() && (shardingRule.getDatabaseShardingStrategy(tableRule.get()) instanceof HintShardingStrategy
                    || shardingRule.getTableShardingStrategy(tableRule.get()) instanceof HintShardingStrategy)) {
                return true;
            }
        }
        return false;
    }

//數(shù)據(jù)源名稱(chēng)
spring.shardingsphere.datasource.names=ds0,ds1
//ds0配置
spring.shardingsphere.datasource.ds0.type=org.apache.commons.dbcp.BasicDataSource
spring.shardingsphere.datasource.ds0.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds0.url=jdbc:mysql://localhost:3306/ds0
spring.shardingsphere.datasource.ds0.username=root
spring.shardingsphere.datasource.ds0.password=
//ds1配置
spring.shardingsphere.datasource.ds1.type=org.apache.commons.dbcp.BasicDataSource
spring.shardingsphere.datasource.ds1.driver-class-name=com.mysql.jdbc.Driver
spring.shardingsphere.datasource.ds1.url=jdbc:mysql://localhost:3306/ds1
spring.shardingsphere.datasource.ds1.username=root
spring.shardingsphere.datasource.ds1.password=
//分表規(guī)則
spring.shardingsphere.sharding.tables.t_order.actual-data-nodes=ds$->{0..1}.t_order$->{0..1}
spring.shardingsphere.sharding.tables.t_order.table-strategy.inline.sharding-column=order_id
spring.shardingsphere.sharding.tables.t_order.table-strategy.inline.algorithm-expressinotallow=t_order$->{order_id % 2}
spring.shardingsphere.sharding.tables.t_order_item.actual-data-nodes=ds$->{0..1}.t_order_item$->{0..1}
spring.shardingsphere.sharding.tables.t_order_item.table-strategy.inline.sharding-column=order_id
spring.shardingsphere.sharding.tables.t_order_item.table-strategy.inline.algorithm-expressinotallow=t_order_item$->{order_id % 2}
//默認(rèn)分庫(kù)規(guī)則
spring.shardingsphere.sharding.default-database-strategy.inline.sharding-column=user_id
spring.shardingsphere.sharding.default-database-strategy.inline.algorithm-expressinotallow=ds$->{user_id % 2}

//數(shù)據(jù)源名稱(chēng)
vivo.it.sharding.datasource.names = ds0,ds1
//ds0配置
vivo.it.sharding.datasource.ds0.url = jdbc:mysql://localhost:3306/ds1
vivo.it.sharding.datasource.ds0.username = root
vivo.it.sharding.datasource.ds0.password =
//ds1配置
vivo.it.sharding.datasource.ds1.url = jdbc:mysql://localhost:3306/ds1
vivo.it.sharding.datasource.ds1.username = root
vivo.it.sharding.datasource.ds1.password =
//分表規(guī)則
vivo.it.sharding.table.rule.config = [{"logicTable":"t_order,t_order_item","tableRange":"0..1","shardingColumn":"order_id ","algorithmExpression":"order_id %2"}]
//默認(rèn)分庫(kù)規(guī)則
vivo.it.sharding.default.db.rule.config = {"shardingColumn":"user_id","algorithmExpression":"user_id %2"}