Spring(十)通过动态代理(JDK的Proxy)和cglib实现AOP技术

目标对象的所有接口方法

package test.spring.service;public interface PersonService {public String getPersonName(Integer id);public void save(String name);}

目标对象

package test.spring.service.impl;import test.spring.service.PersonService;//代理对象实现目标对象所有接口public class PersonServiceBean implements PersonService {private String user = null;public PersonServiceBean() {}public PersonServiceBean(String user) {super();this.user = user;}public String getUser() {return user;}public void setUser(String user) {this.user = user;}@Overridepublic String getPersonName(Integer id) {// TODO Auto-generated method stubreturn "getPersonName";}@Overridepublic void save(String name) {// TODO Auto-generated method stubSystem.out.println("save()->>" + name);}}

代理对象，拦截所有业务方法，根据user是否为null判断用户是否有权限,有权限就允许执行业务方法，无权限就不执行。

package test.spring.aop;import java.lang.reflect.InvocationHandler;import java.lang.reflect.Method;import java.lang.reflect.Proxy;import test.spring.service.impl.PersonServiceBean;public class ProxyFactory implements InvocationHandler {private Object proxyObject;// 创建代理对象实例public Object createProxyIntance(Object proxyObject) {this.proxyObject = proxyObject;/* * 第一个参数：类装载器* 第二个参数：取得目标对象的接口,Proxy会将这些接口全部实现* 第三个参数：一个回调函数，确定实现哪个类的接口 */return Proxy.newProxyInstance(this.proxyObject.getClass().getClassLoader(), this.proxyObject.getClass().getInterfaces(),this);}/* * 第一个参数：代理对象 * 第二个参数：被拦截到的方法 * 第三个参数：方法的输入参数 */@Overridepublic Object invoke(Object proxy, Method method, Object[] args)throws Throwable {PersonServiceBean personServiceBean = (PersonServiceBean) this.proxyObject;Object target = null;// user不为空说明有权限if (personServiceBean.getUser() != null) {// 把对代理对象方法的调用委派给目标对象target = method.invoke(proxyObject, args);}return target;}}

权限测试

package test.spring.junit;import static org.junit.Assert.*;import org.junit.Test;import test.spring.aop.ProxyFactory;import test.spring.service.PersonService;import test.spring.service.impl.PersonServiceBean;public class AOPTest {@Testpublic void test() {ProxyFactory pFactory = new ProxyFactory();// PersonService pService=(PersonService)// pFactory.createProxyIntance(new PersonServiceBean("kkk"));// 改为默认函数pService.save("ppp")就执行不了，因为前面的user=null,相当于没有权限执行PersonService pService = (PersonService) pFactory.createProxyIntance(new PersonServiceBean());pService.save("ppp");}}

以上适用于目标对象实现了接口的情况，如果目标对象没有接口，就会选择用Cglib

首先导入cglib-nodep-2.1_3.jar

package test.spring.service.impl;//代理对象实现目标对象所有接口public class PersonServiceBean2 {private String user = null;public PersonServiceBean2() {}public PersonServiceBean2(String user) {super();this.user = user;}public String getUser() {return user;}public void setUser(String user) {this.user = user;}public void save(String name) {// TODO Auto-generated method stubSystem.out.println("save()->>" + name);}}package test.spring.aop;import java.lang.reflect.Method;import test.spring.service.impl.PersonServiceBean2;import net.sf.cglib.proxy.Callback;import net.sf.cglib.proxy.Enhancer;import net.sf.cglib.proxy.MethodInterceptor;import net.sf.cglib.proxy.MethodProxy;//目标对象没有接口public class CglibProxyFactory implements MethodInterceptor {private Object proxyObject;// 创建代理对象实例public Object createProxyIntance(Object proxyObject) {this.proxyObject = proxyObject;Enhancer enhancer = new Enhancer();/* * 需设置父类，即目标类。创建的对象继承目标类，对目标类中 * 所有非final的所有方法进行覆盖，然后在覆盖的代码里面 * 添加一些自身的代码 */enhancer.setSuperclass(this.proxyObject.getClass());enhancer.setCallback((Callback) this);return enhancer.create();}/* * 第一个参数：代理对象本身 * 第二个参数：被拦截到的方法 * 第三个参数：方法的参数 * 第四个参数：方法的代理对象 */// 当代理对象的业务方法被回调的时候会调用这个方法@Overridepublic Object intercept(Object proxy, Method method, Object[] args,MethodProxy methodProxy) throws Throwable {PersonServiceBean2 personServiceBean = (PersonServiceBean2) this.proxyObject;Object target = null;// user不为空说明有权限if (personServiceBean.getUser() != null) {// 把对方法的调用委派给目标对象target = methodProxy.invoke(proxyObject, args);}return target;}}package test.spring.junit;import static org.junit.Assert.*;import org.junit.Test;import test.spring.aop.CglibProxyFactory;import test.spring.aop.ProxyFactory;import test.spring.service.PersonService;import test.spring.service.impl.PersonServiceBean;import test.spring.service.impl.PersonServiceBean2;public class AOPTest2 {@Testpublic void test() {CglibProxyFactory pFactory = new CglibProxyFactory();// 此时PersonServiceBean没有接口PersonServiceBean2 pService = (PersonServiceBean2) pFactory.createProxyIntance(new PersonServiceBean2("kkk"));pService.save("ppp");}}

，如果可以，我真想和你一直旅行。或许是某个未开发的荒凉小岛，

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