AOP之Proxy技术实现AOP功能

AOP编程其实是很简单的事情，纵观AOP编程，程序员只需要参与三个部分： 1、定义普通业务组件 2、定义切入点，一个切入点可能横切多个业务组件 3、定义增强处理，增强处理就是在AOP框架为普通业务组件织入的处理动作

所以进行AOP编程的关键就是定义切入点和定义增强处理，一旦定义了合适的切入点和增强处理，AOP框架将自动生成AOP代理，即：代理对象的方法=增强处理+被代理对象的方法** PersonServer.java

package liuyanxi.service; public interface PersonService { public void save(String name); public void update(String name, Integer personid); public String getPersonName(Integer personid); }

PersonServiceBean.java

package liuyanxi.service.impl; import liuyanxi.service.PersonService; public class PersonServiceBean implements PersonService{ private String user = null; public String getUser() { return user; } public PersonServiceBean(){} public PersonServiceBean(String user){ this.user = user; } public String getPersonName(Integer personid) { System.out.println("我是getPersonName()方法"); return "xxx"; } 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"); } }

JDKProxyFactory.java

package liuyanxi.aop; import java.lang.reflect.InvocationHandler; import java.lang.reflect.Method; import java.lang.reflect.Proxy; import liuyanxie.impl.PersonServiceBean; public class JDKProxyFactory implements InvocationHandler{ private Object targetObject; public Object createProxyIntance(Object targetObject){ this.targetObject = targetObject; return Proxy.newProxyInstance(this.targetObject.getClass().getClassLoader(), this.targetObject.getClass().getInterfaces(), this); } public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {//环绕通知 PersonServiceBean bean = (PersonServiceBean) this.targetObject; Object result = null; if(bean.getUser()!=null){ //..... advice()-->前置通知 try { result = method.invoke(targetObject, args); // afteradvice() -->后置通知 } catch (RuntimeException e) { //exceptionadvice()--> 例外通知 }finally{ //finallyadvice(); -->最终通知 } } return result; } }

Test.java

package junit.test; import org.junit.BeforeClass; import org.junit.Test; import liuyanxi.aop.CGlibProxyFactory; import liuyanxi.aop.JDKProxyFactory; import liuyanxi.service.PersonService; import liuyanxi.service.impl.PersonServiceBean; public class AOPTest { @BeforeClass public static void setUpBeforeClass() throws Exception { } @Test public void proxyTest(){ JDKProxyFactory factory = new JDKProxyFactory(); PersonService service = (PersonService) factory.createProxyIntance(new PersonServiceBean("xxx")); service.save("888"); } @Test public void proxyTest2(){ CGlibProxyFactory factory = new CGlibProxyFactory(); PersonServiceBean service = (PersonServiceBean) factory.createProxyIntance(new PersonServiceBean("xxx")); service.save("999"); } }

通过在代理对象设置切面拦截方法，管理目标对象，体现了java设计模式中的代理模式