static class PersonDAO {
  public void save(String name) {
    System.out.println("PersonDAO save method invoke...") ;
  }
}
static class PersonService {
  private PersonDAO dao ;
  public PersonService(PersonDAO dao) {
    this.dao = dao ;
  }
  public void save(String name) {
    System.out.println("PersonService save method inovke...") ;
    this.dao.save(name) ;
  }
}


static class PersonManager {
  private PersonService ps ;
  public void setPs(PersonService ps) {
    this.ps = ps ;
  }
  public void index(String name) {
    System.out.println("PersonManager index method invoke...") ;
    this.ps.save(name) ;
  }
}

// 實(shí)例化上面的類
PersonDAO dao = new PersonDAO() ;
PersonService target = new PersonService(dao) ;


PersonManager pm = new PersonManager() ;


Class<?> clazz = PersonManager.class ;
String methodName = "index" ;
// 定義切入點(diǎn)
ControlFlowPointcut pointcut = new ControlFlowPointcut(clazz, methodName) ;
// 定義通知
MethodInterceptor logInterceptor = invocation -> {
  System.out.println("before log...") ;
  Object ret = invocation.proceed() ;
  System.out.println("after log...") ;
  return ret ;
} ;
// 定義切面


DefaultPointcutAdvisor advisor = new DefaultPointcutAdvisor(pointcut, logInterceptor) ;
// 通過(guò)ProxyFactory創(chuàng)建代理對(duì)象，創(chuàng)建的是PersonService對(duì)象的代理
ProxyFactory factory = new ProxyFactory(target) ;
factory.addAdvisor(advisor) ;
// 基于CGLIB生成代理
factory.setProxyTargetClass(true) ;
PersonService ps = (PersonService) factory.getProxy() ;


pm.setPs(ps) ;


pm.index("張三") ;

PersonManager index method invoke...
before log...
PersonService save method inovke...
PersonDAO save method invoke...
after log...

public class ControlFlowPointcut implements Pointcut, ClassFilter, MethodMatcher, Serializable {
  private final Class<?> clazz;
  @Nullable
  private final String methodName;
  // 對(duì)應(yīng)類級(jí)別的匹配全部返回true，就是都匹配
  @Override
  public boolean matches(Class<?> clazz) {
    return true;
  }
  // 方法匹配，直接true
  @Override
  public boolean matches(Method method, Class<?> targetClass) {
    return true;
  }
  // 這里是關(guān)鍵，只有isRuntime返回了true才有可能調(diào)用下面3個(gè)參數(shù)的matches方法
  @Override
  public boolean isRuntime() {
    return true;
  }
  // 該方法的調(diào)用需要上面2個(gè)參數(shù)的matches方法返回true且isRuntime方法也返回true才會(huì)調(diào)用這里
  @Override
  public boolean matches(Method method, Class<?> targetClass, Object... args) {
    // 遍歷當(dāng)前線程的執(zhí)行棧情況（也就是當(dāng)前方法的調(diào)用棧情況）
    for (StackTraceElement element : new Throwable().getStackTrace()) {
      // 這里就開(kāi)始判斷當(dāng)前執(zhí)行的類是否與給定的類相同 && 當(dāng)前設(shè)置的methodName為空或者當(dāng)前棧執(zhí)行的方法名與給定的方法名相同
      if (element.getClassName().equals(this.clazz.getName()) &&
          (this.methodName == null || element.getMethodName().equals(this.methodName))) {
        // 最終這里只有返回了true，我們上面的通知MethodInterceptor才會(huì)被執(zhí)行
        return true;
      }
    }
    return false;
  }
}

// 指明要匹配的類
Class<?> clazz = PersonManager.class ;
// 指明要匹配的方法名
String methodName = "index" ;
/** 
 * 將傳入到切入點(diǎn)中；而在該切入點(diǎn)的matches方法中進(jìn)行了判斷，
 * 整個(gè)執(zhí)行的線程棧中的所有類及方法是否與這里給定的相同，
 * 只有相同了攔截器才能執(zhí)行
 */
ControlFlowPointcut pointcut = new ControlFlowPointcut(clazz, methodName) ;