Spring AOP - 从方法返回的代理对象

Question

在这个例子中：

public class ConnectionPool {
  public java.sql.Connection getConnection() {
      ...
  }
}

@Bean
@Scope("singleton")
public ConnectionPool connectionPool(...) throws Exception {
    return new ConnectionPoolImpl(...);
}

我想监控从 getConnection() 返回的 Connection 对象上对 java.sql.Connection.close() 的调用。

我尝试在 getConnection() 方法中添加@Lookup，但没有效果。

如何让 Spring 代理 java.sql.Connection 对象？

Answer 1

可以为ConnectionPool创建代理，并在bean创建方法中返回代理

@Bean
@Scope("singleton")
public ConnectionPool connectionPool(...) throws Exception {
    ConnectionPoolImpl delegate = new ConnectionPoolImpl(...);
    ConnectionPoolCallHandler callHandler = new ConnectionPoolCallHandler(delegate);
    ConnectionPool proxy = Proxy.newProxyInstance(
                ConnectionPool.getClass().getClassLoader(),
                new Class[]{ConnectionPool.class},
                callHandler);

//    return new ConnectionPoolImpl(...);
    return proxy;
}

和

public class ConnectionPoolCallHandler implements InvocationHandler {
    private ConnectionPoolImpl delegate;
    public ConnectionPoolCallHandler(ConnectionPoolImpl delegate) {
        this.delegate=delegate;
    }
    public Object invoke(Object proxy, Method method, Object[] args)
            throws Throwable {
         //all invoked methods should call 
         //appropriate methods of delegate passing all parameters
         //plus your additional tracking logic here
    }
}

Answer 2

@Pointcut("within(java.sql.Connection.close(..)")
public void closeAspect() {}

@Around("closeAspect()")
public void logAround(ProceedingJoinPoint joinPoint) throws Throwable 
{
  joinPoint.getThis();//Will return the object on which it(close function) is called 
  //Do whatever you want to do here
   joinPoint.proceed();   
  //Do whatever you want to do here
}