動態代理兩種實現方式：jdk動態代理和cglib動態代理

廢話不多說，直接上代碼!

1、首先是接口及其實現方法：

package proxy.test;

public interface UserService {
	public String getName(int id);
	public Integer getAge(int id);
}

package proxy.test;

public class UserServiceImpl implements UserService{

	@Override
	public String getName(int id) {
		System.out.println("getName方法進來了");
		return "fuhongyu";
	}

	@Override
	public Integer getAge(int id) {
		System.out.println("getAge方法進來了");
		return 18;
	}
}

2、jdk動態代理的實現：

實現InvocationHandler 接口，重寫invoke方法。

package proxy.test;

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 proxy, Method method, Object[] args) throws Throwable {
		if("getAge".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 proxy.test;

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

public class JdkTest {
	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));
	}	
}

3、cglib動態代理實現：

實現MethodInterceptor接口，重寫intercept方法。

package proxy.test;
import java.lang.reflect.Method;

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

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("after:"+methodProxy.getSuperName());
		return o1;
	}
}

package proxy.test;

import org.springframework.cglib.proxy.Enhancer;

public class CglibTest {
	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);
	}
}