Java动态代理三--模拟AOP实现

以下案例模拟AOP实现

目录结构



接口PersonService

package com.ljq.service;

public interface PersonService {
public void save(String name);
public void update(String name, Integer personId);
public String getPersonName(Integer personId);
}



实现类PersonServiceBean

package com.ljq.service.impl;

import com.ljq.service.PersonService;

public class PersonServiceBean implements PersonService {
private String user = null;

public PersonServiceBean() {
super();
}

public PersonServiceBean(String user) {
super();
this.user = user;
}

public String getPersonName(Integer personId) {
System.out.println("我是getPersonName()方法");
return "get";
}

public void save(String name) {
System.out.println("我是save()方法");
}

public void update(String name, Integer personId) {
System.out.println("我是update()方法");
}

public String getUser() {
return user;
}

public void setUser(String user) {
this.user = user;
}
}



动态代理类JDKProxyFactory

package com.ljq.aop;

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

import com.ljq.service.impl.PersonServiceBean;

public class JDKProxyFactory implements InvocationHandler {
//要代理的原始对象
private Object targer;

/**
* 创建动态代理
*
* @param targer 要代理的原始对象
* @return
*/
public Object createProxyInstance(Object targer){
this.targer=targer;
return Proxy.newProxyInstance(
this.targer.getClass().getClassLoader(),
this.targer.getClass().getInterfaces(),
this);
}

public Object invoke(Object proxy, Method method, Object[] args)
throws Throwable {
Object result = null;
PersonServiceBean bean = (PersonServiceBean) this.targer;
if (bean.getUser() != null) {
// 前置通知
doBefore();
try {
result = method.invoke(targer, args);
// 后置通知
doAfter();
} catch (Exception e) {
// 例外通知
doException();
} finally {
// 最终通知
doFinally();
}
}
return result;
}

private void doBefore() {
System.out.println("我是前置通知");
}

private void doAfter() {
System.out.println("我是后置通知");
}

private void doException() {
System.out.println("我是例外通知");
}

private void doFinally() {
System.out.println("我是最终通知");
}

}



动态代理类CGlibProxyFactory：使用CGLIB技术

package com.ljq.aop;

import java.lang.reflect.Method;

import com.ljq.service.impl.PersonServiceBean;

import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;

public class CGlibProxyFactory implements MethodInterceptor{
private Object target;

public Object createProxyInstance(Object target){
this.target=target;
Enhancer enhancer=new Enhancer();
enhancer.setSuperclass(this.target.getClass());//非final
enhancer.setCallback(this);
return enhancer.create();
}

public Object intercept(Object proxy, Method method, Object[] args,
MethodProxy methodProxy) throws Throwable {
Object result=null;
PersonServiceBean bean=(PersonServiceBean)this.target;
if(bean.getUser()!=null){
// 前置通知
doBefore();
try {
result = methodProxy.invoke(target, args);
// 后置通知
doAfter();
} catch (Exception e) {
// 例外通知
doException();
} finally {
// 最终通知
doFinally();
}
}
return result;
}

private void doBefore() {
System.out.println("我是前置通知");
}

private void doAfter() {
System.out.println("我是后置通知");
}

private void doException() {
System.out.println("我是例外通知");
}

private void doFinally() {
System.out.println("我是最终通知");
}

}



测试类AopTest

package com.ljq.test;

import com.ljq.aop.CGlibProxyFactory;
import com.ljq.aop.JDKProxyFactory;
import com.ljq.service.PersonService;
import com.ljq.service.impl.PersonServiceBean;

public class AopTest {

public static void main(String[] args) {
proxyTest();
proxyTest2();
}

private static void proxyTest() {
JDKProxyFactory jdkProxyFactory=new JDKProxyFactory();
PersonService personService=(PersonService)jdkProxyFactory.
createProxyInstance(new PersonServiceBean("zhangsan"));
personService.getPersonName(1);
}

private static void proxyTest2() {
CGlibProxyFactory cglibProxyFactory=new CGlibProxyFactory();
PersonServiceBean bean=(PersonServiceBean)cglibProxyFactory.
createProxyInstance(new PersonServiceBean("lisi"));
bean.save("a");

}
}



运行结果