Java动态代理

标签：java   动态代理   

动态代理涉及到的5个类：1. 接口Interface  2.被代理类 3.动态代理处理类  4.测试类  5.生成的代理类

整个过程就是：先调用Proxy.newProxyInstance()方法，传入接口，class loader以及动态代理处理类（被代理类是处理类的一个属性，作为参数传入），这个方法生成接口的一个实现类（代理类），这个代理类继承自Proxy类，所以可以得到传入到Proxy类的动态代理处理类，代理类还实现了接口的所有方法，每个方法体就是去调用动态代理处理类的invoke方法，把方法体里被调用时传来的参数再传到invoke方法里去，这样就实现了动态代理~

1. 接口Interface

package proxy;

public interface Interface {
	void doSomething();

	void somethingElse(String args);
}

2.被代理类

package proxy;

public class RealObject implements Interface {

	@Override
	public void doSomething() {
		// TODO Auto-generated method stub
		System.out.println("realObject do something");
	}

	@Override
	public void somethingElse(String args) {
		// TODO Auto-generated method stub
		System.out.println("realObject something else ,args:" + args);
	}

}

package proxy;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;

public class ProxyHandler implements InvocationHandler {
	private RealObject realObj;

	public ProxyHandler(RealObject realObj) {
		// TODO Auto-generated constructor stub
		this.realObj = realObj;
	}

	@Override
	public Object invoke(Object arg0, Method arg1, Object[] arg2)
			throws Throwable {
		// TODO Auto-generated method stub
		System.out.println("before proxy");
		arg1.invoke(realObj, arg2);
		System.out.println("after proxy");
		return null;
	}

}

package proxy;

import java.lang.reflect.Proxy;

public class ProxyTest {

	public static void main(String[] args) {
		RealObject realObj = new RealObject();
		Interface proxy = (Interface) Proxy.newProxyInstance(
				Interface.class.getClassLoader(),
				new Class[] { Interface.class }, new ProxyHandler(realObj));
		System.out.println(proxy.getClass());
		proxy.doSomething();
		proxy.somethingElse("dayna");
		//
//        byte[] proxyClassFile = ProxyGenerator.generateProxyClass(
//                "DaynaProxy", new Class[] { Interface.class });
	}
}

import com.pactera.oscar.fwapp2.pqs.eb.view.Interface;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.lang.reflect.UndeclaredThrowableException;

public final class DaynaProxy extends Proxy
  implements Interface
{
  private static Method m1;
  private static Method m0;
  private static Method m3;
  private static Method m4;
  private static Method m2;

  public DaynaProxy(InvocationHandler paramInvocationHandler)
    throws 
  {
    super(paramInvocationHandler);
  }

  public final boolean equals(Object paramObject)
    throws 
  {
    try
    {
      return ((Boolean)this.h.invoke(this, m1, new Object[] { paramObject })).booleanValue();
    }
    catch (RuntimeException localRuntimeException)
    {
      throw localRuntimeException;
    }
    catch (Throwable localThrowable)
    {
    }
    throw new UndeclaredThrowableException(localThrowable);
  }

  public final int hashCode()
    throws 
  {
    try
    {
      return ((Integer)this.h.invoke(this, m0, null)).intValue();
    }
    catch (RuntimeException localRuntimeException)
    {
      throw localRuntimeException;
    }
    catch (Throwable localThrowable)
    {
    }
    throw new UndeclaredThrowableException(localThrowable);
  }

  public final void doSomething()
    throws 
  {
    try
    {
      this.h.invoke(this, m3, null);
      return;
    }
    catch (RuntimeException localRuntimeException)
    {
      throw localRuntimeException;
    }
    catch (Throwable localThrowable)
    {
    }
    throw new UndeclaredThrowableException(localThrowable);
  }

  public final void somethingElse(String paramString)
    throws 
  {
    try
    {
      this.h.invoke(this, m4, new Object[] { paramString });
      return;
    }
    catch (RuntimeException localRuntimeException)
    {
      throw localRuntimeException;
    }
    catch (Throwable localThrowable)
    {
    }
    throw new UndeclaredThrowableException(localThrowable);
  }

  public final String toString()
    throws 
  {
    try
    {
      return (String)this.h.invoke(this, m2, null);
    }
    catch (RuntimeException localRuntimeException)
    {
      throw localRuntimeException;
    }
    catch (Throwable localThrowable)
    {
    }
    throw new UndeclaredThrowableException(localThrowable);
  }

  static
  {
    try
    {
      m1 = Class.forName("java.lang.Object").getMethod("equals", new Class[] { Class.forName("java.lang.Object") });
      m0 = Class.forName("java.lang.Object").getMethod("hashCode", new Class[0]);
      m3 = Class.forName("com.pactera.oscar.fwapp2.pqs.eb.view.Interface").getMethod("doSomething", new Class[0]);
      m4 = Class.forName("com.pactera.oscar.fwapp2.pqs.eb.view.Interface").getMethod("somethingElse", new Class[] { Class.forName("java.lang.String") });
      m2 = Class.forName("java.lang.Object").getMethod("toString", new Class[0]);
      return;
    }
    catch (NoSuchMethodException localNoSuchMethodException)
    {
      throw new NoSuchMethodError(localNoSuchMethodException.getMessage());
    }
    catch (ClassNotFoundException localClassNotFoundException)
    {
    }
    throw new NoClassDefFoundError(localClassNotFoundException.getMessage());
  }
}

Java动态代理

标签：java   动态代理   

原文地址：http://blog.csdn.net/gaga704/article/details/46647579