Java动态代理的两种实现方式：

package cn.hc.domain;

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

/**
 * 代理对象创建的工厂类
 * @author hc
 *
 */
public class JDKProxyFactory implements InvocationHandler{
	//被代理对象
	private Object target;
	public JDKProxyFactory(Object target){
		this.target=target;
	}
	//创建代理
	public Object createProxy(){
		//三个参数：类加载器 实现接口 invocationHandler
		return Proxy.newProxyInstance(target.getClass().getClassLoader(), target.getClass().getInterfaces(), this);
	}
	public Object invoke(Object arg0, Method arg1, Object[] arg2)
			throws Throwable {
		// TODO Auto-generated method stub
		//调用目标真是的方法
		System.out.println("日志已经被记录");
		return arg1.invoke(target, arg2);
	}
}

package cn.hc.domain;
//代理对象的接口
public interface  UserDao {
	public void save();
	public void update();
}package cn.hc.domain;
/**
 * 被代理的目标对象
 * @author hc
 *
 */
public class UserDaoImpl implements UserDao {

	public void save() {
		// TODO Auto-generated method stub
		System.out.println("添加用户");
	}

	public void update() {
		// TODO Auto-generated method stub
		System.out.println("更新用户");
	}

}
//测试类package cn.hc.domain;

import org.junit.Test;

public class TestProxy {
	@Test
	public void testJdkProxy(){
		//测试jdk动态代理
		//1真实目标对象
		UserDao userDao=new UserDaoImpl();
		//System.out.println(userDao);
		UserDao proxy=(UserDao) new JDKProxyFactory(userDao).createProxy();
		proxy.save();
		proxy.update();
	}
}

package cn.hc.cglibProxy;

import java.lang.reflect.Method;

import org.springframework.cglib.proxy.Enhancer;
import org.springframework.cglib.proxy.MethodInterceptor;
import org.springframework.cglib.proxy.MethodProxy;

public class CGlibProxyFactory implements MethodInterceptor{
	private Object target;
	public CGlibProxyFactory(Object target){
		this.target=target;
	}
	//创建代理对象的方法
	public Object createProxy() {
		//创建Enhance对象
		Enhancer enhancer=new Enhancer();
		//cglib创建代理，对目标对象创建子类对象
		enhancer.setSuperclass(target.getClass());
		//传入callback对象，对目标增强
		enhancer.setCallback(this);
		return enhancer.create();
	}
	//arg3 用于执行父类的方法
	public Object intercept(Object arg0, Method arg1, Object[] arg2,
			MethodProxy arg3) throws Throwable {
		// TODO Auto-generated method stub
		System.out.println("开始记录日志");
		return arg1.invoke(target,arg2);
	}
}

package cn.hc.cglibProxy;

public class ProductDao {
	public void add(){
		System.out.println("添加");
	}
	public void delete(){
		System.out.println("删除");
	}
}
//测试方法
package cn.hc.cglibProxy;

import org.junit.Test;

public class CGlibTest {
	@Test
  public void test1(){
	  //创建目标对象
	  ProductDao dao=new ProductDao();
	  ProductDao proxy=(ProductDao) new CGlibProxyFactory(dao).createProxy();
	  proxy.add();
	  proxy.delete();
  }
}