java 动态代理的方法总结

package com.meituan.hyt.test3.service; 
 
 
public interface UserService { 
  public String getName(int id); 
 
  public Integer getAge(int id); 
} 

package com.meituan.hyt.test3.service.impl; 
 
import com.meituan.hyt.test3.service.UserService; 
 
 
public class UserServiceImpl implements UserService { 
  @Override 
  public String getName(int id) { 
    System.out.println("------getName------"); 
    return "Tom"; 
  } 
 
  @Override 
  public Integer getAge(int id) { 
    System.out.println("------getAge------"); 
    return 10; 
  } 
} 

package com.meituan.hyt.test3.jdk; 
 
import java.lang.reflect.InvocationHandler; 
import java.lang.reflect.Method; 
 
 
public class MyInvocationHandler implements InvocationHandler { 
  private Object target; 
 
  MyInvocationHandler() { 
    super(); 
  } 
 
  MyInvocationHandler(Object target) { 
    super(); 
    this.target = target; 
  } 
 
  @Override 
  public Object invoke(Object o, Method method, Object[] args) throws Throwable { 
    if("getName".equals(method.getName())){ 
      System.out.println("++++++before " + method.getName() + "++++++"); 
      Object result = method.invoke(target, args); 
      System.out.println("++++++after " + method.getName() + "++++++"); 
      return result; 
    }else{ 
      Object result = method.invoke(target, args); 
      return result; 
    } 
 
  } 
} 

package com.meituan.hyt.test3.jdk; 
 
import com.meituan.hyt.test3.service.UserService; 
import com.meituan.hyt.test3.service.impl.UserServiceImpl; 
 
import java.lang.reflect.InvocationHandler; 
import java.lang.reflect.Proxy; 
 
 
public class Main1 { 
  public static void main(String[] args) { 
    UserService userService = new UserServiceImpl(); 
    InvocationHandler invocationHandler = new MyInvocationHandler(userService); 
    UserService userServiceProxy = (UserService)Proxy.newProxyInstance(userService.getClass().getClassLoader(), 
        userService.getClass().getInterfaces(), invocationHandler); 
    System.out.println(userServiceProxy.getName(1)); 
    System.out.println(userServiceProxy.getAge(1)); 
  } 
} 

++++++before getName++++++
------getName------
++++++after getName++++++
Tom
------getAge------
10

 net.sf.cglib.proxy.Enhancer – 主要的增强类
  net.sf.cglib.proxy.MethodInterceptor – 主要的方法拦截类，它是Callback接口的子接口，需要用户实现
  net.sf.cglib.proxy.MethodProxy – JDK的java.lang.reflect.Method类的代理类，可以方便的实现对源对象方法的调用,如使用：
  Object o = methodProxy.invokeSuper(proxy, args);//虽然第一个参数是被代理对象，也不会出现死循环的问题。

net.sf.cglib.proxy.MethodInterceptor接口是最通用的回调（callback）类型，它经常被基于代理的AOP用来实现拦截（intercept）方法的调用。这个接口只定义了一个方法
public Object intercept(Object object, java.lang.reflect.Method method,
Object[] args, MethodProxy proxy) throws Throwable;

package com.meituan.hyt.test3.cglib; 
 
 
import net.sf.cglib.proxy.MethodInterceptor; 
import net.sf.cglib.proxy.MethodProxy; 
 
import java.lang.reflect.Method; 
 
 
public class CglibProxy implements MethodInterceptor { 
  @Override 
  public Object intercept(Object o, Method method, Object[] args, MethodProxy methodProxy) throws Throwable { 
    System.out.println("++++++before " + methodProxy.getSuperName() + "++++++"); 
    System.out.println(method.getName()); 
    Object o1 = methodProxy.invokeSuper(o, args); 
    System.out.println("++++++before " + methodProxy.getSuperName() + "++++++"); 
    return o1; 
  } 
} 

package com.meituan.hyt.test3.cglib; 
 
import com.meituan.hyt.test3.service.UserService; 
import com.meituan.hyt.test3.service.impl.UserServiceImpl; 
import net.sf.cglib.proxy.Enhancer; 
 
 
 
public class Main2 { 
  public static void main(String[] args) { 
    CglibProxy cglibProxy = new CglibProxy(); 
 
    Enhancer enhancer = new Enhancer(); 
    enhancer.setSuperclass(UserServiceImpl.class); 
    enhancer.setCallback(cglibProxy); 
 
    UserService o = (UserService)enhancer.create(); 
    o.getName(1); 
    o.getAge(1); 
  } 
} 

++++++before CGLIB$getName$0++++++
getName
------getName------
++++++before CGLIB$getName$0++++++
++++++before CGLIB$getAge$1++++++
getAge
------getAge------
++++++before CGLIB$getAge$1++++++