Two implementations of the Java Dynamic Agent:

Way one: the traditional agent

Package Cn.hc.domain;import Java.lang.reflect.invocationhandler;import Java.lang.reflect.method;import java.lang.reflect.proxy;/** * Factory class created by proxy object * @author HC * */public class Jdkproxyfactory implements invocationhandler{//is represented Objects Private Object Target;public jdkproxyfactory (object target) {This.target=target;} Create proxy public Object Createproxy () {//three parameters: Class loader implementation Interface Invocationhandlerreturn Proxy.newproxyinstance (Target.getclass () . getClassLoader (), Target.getclass (). Getinterfaces (), this);} public object Invoke (object arg0, Method arg1, object[] arg2) throws Throwable {//TODO auto-generated Method stub//call Target really. Method System.out.println ("Log has been recorded"); return Arg1.invoke (target, arg2);}}

The flaw in this approach is that the class being proxied must implement an interface

Package cn.hc.domain;//Proxy Object Interface public interface  Userdao {public void Save ();p ublic void Update ();} Package cn.hc.domain;/** * Target object of the agent * @author HC * */public class Userdaoimpl implements Userdao {public void Save () {//T ODO auto-generated Method StubSystem.out.println ("Add User"); public void Update () {//TODO auto-generated method stubSystem.out.println ("Update User");}} Test class Package Cn.hc.domain;import Org.junit.test;public class Testproxy {@Testpublic void Testjdkproxy () {//Test JDK dynamic agent// 1 Real target object Userdao userdao=new Userdaoimpl ();//system.out.println (Userdao); Userdao proxy= (Userdao) New Jdkproxyfactory (Userdao). Createproxy ();p roxy.save ();p roxy.update ();}}

Test results:

Log has been recorded

Add user

Log has been recorded

Update user

Mode 2:cglib Dynamic Agent

Package Cn.hc.cglibproxy;import Java.lang.reflect.method;import Org.springframework.cglib.proxy.enhancer;import Org.springframework.cglib.proxy.methodinterceptor;import Org.springframework.cglib.proxy.methodproxy;public Class Cglibproxyfactory implements Methodinterceptor{private object Target;public cglibproxyfactory (object target) { This.target=target;} Methods for creating Proxy objects public Object Createproxy () {//Create enhance Object Enhancer enhancer=new enhancer ();//cglib Create agent, Creates a subclass object Enhancer.setsuperclass (Target.getclass ()) on the target object, or the callback object, which is enhanced by the target enhancer.setcallback (this); Enhancer.create ();} Arg3 method for executing the parent class public Object intercept (object arg0, Method Arg1, object[] arg2,methodproxy arg3) throws Throwable {//TOD O auto-generated Method StubSystem.out.println ("Start recording log"); return Arg1.invoke (TARGET,ARG2);}}

Package Cn.hc.cglibproxy;public class Productdao {public void Add () {System.out.println ("add");} public void Delete () {System.out.println ("delete");}} Test method Package Cn.hc.cglibproxy;import Org.junit.test;public class Cglibtest {@Test public  void Test1 () {  // Create target object  Productdao dao=new Productdao ();  Productdao proxy= (Productdao) New Cglibproxyfactory (dao). Createproxy ();  Proxy.add ();  Proxy.delete ();  }}

Two implementations of the Java Dynamic Agent: