// SpringFactoriesLoader核心代碼示例（SpringBoot 2.x）
public final class SpringFactoriesLoader{
    // ...
    public static <T> List<T> loadFactories(Class<T> factoryType, @Nullable ClassLoader classLoader){
        // ... 
        // 加載META-INF/spring.factories中的配置
        Map<String, List<String>> result = loadSpringFactories(classLoader);
        // ...
    }
    
    private static Map<String, List<String>> loadSpringFactories(@Nullable ClassLoader classLoader) {
        // 從類路徑中加載所有META-INF/spring.factories文件
        // ...
    }
    // ...
}

org.springframework.boot.autoconfigure.EnableAutoCnotallow=\
com.example.FooAutoConfiguration,\
com.example.BarAutoConfiguration

com.example.FooAutoConfiguration
com.example.BarAutoConfiguration

// 原來的自動配置類
@Configuration
@ConditionalOnXxx
public class MyAutoConfiguration{
    // ...
}

// 在META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports文件中添加：
// com.example.MyAutoConfiguration

// 示例：注冊ApplicationListener
// SpringBoot 3.0之前：在spring.factories中配置
// org.springframework.context.Applicatinotallow=com.example.MyListener

// SpringBoot 3.0之后：使用@Bean方式注冊
@Configuration
public class MyConfiguration{
    @Bean
    public MyListener myListener(){
        return new MyListener();
    }
}

// 自定義擴(kuò)展點(diǎn)加載器示例
public class MyExtensionLoader{
    public List<MyExtension> loadExtensions(){
        return SpringFactoriesLoader.loadFactories(MyExtension.class, null);
    }
}

// 遷移到新機(jī)制
public class MyExtensionLoader{
    public List<MyExtension> loadExtensions(){
        List<String> classNames = SpringFactoriesLoader.loadFactoryNames(
            MyExtension.class, null);
        // 或者實(shí)現(xiàn)自己的imports文件加載邏輯
        // ...
    }
}

// SpringBoot 3.x中新的SpringFactoriesLoader用法
public final classSpringFactoriesLoader{
    // 過時的方法
    @Deprecated
    public static <T> List<T> loadFactories(Class<T> factoryType, @Nullable ClassLoader classLoader){
        // ...
    }
    
    // 新方法
    public static List<String> loadFactoryNames(Class<?> factoryType, @Nullable ClassLoader classLoader){
        // 加載對應(yīng)的imports文件
        // ...
    }
    
    // ...
}

// 1. 創(chuàng)建配置屬性類
@ConfigurationProperties(prefix = "myapp")
public class MyProperties{
    private boolean enabled = true;
    private String name = "default";
    
    // getter和setter方法
    // ...
}

// 2. 創(chuàng)建自動配置類
@AutoConfiguration// 注意這里使用了@AutoConfiguration而非@Configuration
@EnableConfigurationProperties(MyProperties.class)
@ConditionalOnProperty(prefix= "myapp", name = "enabled", havingValue = "true", matchIfMissing = true)
public class MyAutoConfiguration{
    
    private final MyProperties properties;
    
    public MyAutoConfiguration(MyProperties properties){
        this.properties = properties;
    }
    
    @Bean
    @ConditionalOnMissingBean
    public MyService myService(){
        // 根據(jù)屬性創(chuàng)建服務(wù)
        return new MyServiceImpl(properties.getName());
    }
}

com.example.MyAutoConfiguration

myproject/
├── src/
│   └── main/
│       ├── java/
│       │   └── com/
│       │       └── example/
│       │           ├── MyProperties.java
│       │           ├── MyService.java
│       │           ├── MyServiceImpl.java
│       │           └── MyAutoConfiguration.java
│       └── resources/
│           └── META-INF/
│               └── spring/
│                   └── org.springframework.boot.autoconfigure.AutoConfiguration.imports
└── pom.xml

// SpringBoot 3.0 AOT處理示例
public class SpringAotProcessor{
    public void process(){
        // 1. 讀取imports文件而非掃描spring.factories
        List<String> configurations = readImportsFiles();
        
        // 2. 預(yù)先評估條件而非運(yùn)行時評估
        List<String> effectiveConfigurations = 
            evaluateConditions(configurations, buildTimeProperties);
        
        // 3. 生成代理類而非運(yùn)行時動態(tài)生成
        generateProxies(effectiveConfigurations);
        
        // 4. 生成反射配置
        generateReflectionConfig(effectiveConfigurations);
        
        // 5. 生成資源配置
        generateResourcesConfig();
    }
}

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.experimental</groupId>
        <artifactId>spring-native</artifactId>
        <version>${spring-native.version}</version>
    </dependency>
</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <configuration>
                <image>
                    <builder>paketobuildpacks/builder:tiny</builder>
                    <env>
                        <BP_NATIVE_IMAGE>true</BP_NATIVE_IMAGE>
                    </env>
                </image>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.springframework.experimental</groupId>
            <artifactId>spring-aot-maven-plugin</artifactId>
            <executions>
                <execution>
                    <id>generate</id>
                    <goals>
                        <goal>generate</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

// 舊的方式 - spring.factories配置:
// META-INF/spring.factories:
// org.springframework.boot.autoconfigure.EnableAutoCnotallow=com.example.MyNativeCompatibleConfig

// 新的方式 - imports文件:
// META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports:
// com.example.MyNativeCompatibleConfig

// 自動配置類
@AutoConfiguration
@NativeHint(options = "--enable-url-protocols=http") // GraalVM特定的提示
public class MyNativeCompatibleConfig{
    @Bean
    public MyService myService(){
        return new MyNativeCompatibleService();
    }
}