静态代理

第一种实现(基于接口)：

1》接口

public interface Hello {

void say(String msg); }

2》目标类，至少实现一个接口

public class HelloImpl implements Hello {
      public void say(String msg) {
          System.out.println("Hi,"+msg);     } }

3》代理类(与目标类实现相同接口，从而保证功能一致)

public class HelloProxy implements Hello{
      private Hello hello;     public HelloProxy(Hello hello){
          this.hello = hello;     }     public void say(String msg){
          before();         hello.say(msg);         after();     }     private void before(){
          System.out.println("Before");     }     private void after(){
          System.out.println("After");     } }

3》测试

/**  * @Author LZHL  * @Create 2017-02-19 10:26  * @Description  */ public class Main {
      public static void main(String[] args) throws Exception {
          HelloImpl target = new HelloImpl();         HelloProxy proxy = new HelloProxy(target);         proxy.say("LZHL");     } }

第二种实现(基于目标类)：

1>目标类

public class HelloTarget {
      public void sayHello(String name){
          System.out.println("Hi,"+name);     } }

2>代理类(通过继承目标类，保证功能一致)

public class HelloProxy extends HelloTarget{
  　　private HelloTarget target; 　　public HelloProxy(HelloTarget target){
  　　　　this.target = target; 　　} 　　@Override     public void sayHello(String name) {
          this.before();         target.sayHello(name);         this.after();     }     private void before(){
          System.out.println("Before");     }     private void after(){
          System.out.println("After");     } }

3>测试

public class Main {
      public static void main(String[] args) throws Exception {
         HelloTarget target = new HelloTarget(); 　　　　HelloProxy proxy= new HelloProxy(target);        proxy.sayHello("LZHL");     } }

 

动态代理

动态代理的代理类是在程序运行期间动态生成的，也有两种实现，一种是JDK动态代理，一种是CGLib动态代理

1》JDK动态代理(基于接口实现，与目标类实现相同接口，从而保证功能一致)

/**  * @Author LZHL  * @Create 2017-02-19 12:46  * @Description  */ public class Main {
      public static void main(String[] args){
          final HelloImpl target = new HelloImpl();         Object proxyInstance = Proxy.newProxyInstance(target.getClass().getClassLoader(), target.getClass().getInterfaces(), new InvocationHandler() {
              /*              * proxy: 代理对象              * method: 目标对象的方法对象              * args: 目标对象方法的参数              * return: 目标对象方法的返回值              */             public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                  System.out.println("before");                 Object retValue = method.invoke(target, args);                 System.out.println("after");                 return retValue;             }         });         Hello proxy = (Hello) proxyInstance;         proxy.say("LYX");         //可以把InvocationHandler提取出来，单独写一个类，为了方便大家看，这里我用内部类的形式

class JDKProxy implements InvocationHandler {
              private Object target;             public JDKProxy(Object target){
                  this.target = target;             }             public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                  before();                 Object result = method.invoke(target, args);                 after();                 return result;             }             private void before(){
                  System.out.println("Before");             }             private void after(){
                  System.out.println("After");             }         }         InvocationHandler ih = new JDKProxy(target);         Object proxyInstance2 = Proxy.newProxyInstance(target.getClass().getClassLoader(), target.getClass().getInterfaces(), ih);         Hello proxy2 = (Hello) proxyInstance2;         proxy2.say("LZHL");     } }

2》CGLib动态代理(基于目标类，通过继承目标类，从而保证功能一致)，需要导入cglib-3.2.4.jar包

pom.xml

         
          
              
      
       cglib
               
      
       cglib
               
      
       3.2.4
           
      
    

1)目标类

public class Hi {
      public void sayHi(String msg){
          System.out.println("Hi,"+msg);     } }

2)测试

/**  * @Author LZHL  * @Create 2017-02-19 13:19  * @Description  */ public class Main {
      public static void main(String[] args) {
          Enhancer enhancer = new Enhancer();         //设置父类         enhancer.setSuperclass(Hi.class);         //设置回调函数         enhancer.setCallback(new MethodInterceptor() {
              public Object intercept(Object target, Method method, Object[] args, MethodProxy methodProxy) throws Throwable {
                  System.out.println("before");                 Object retValue = methodProxy.invokeSuper(target, args);                 System.out.println("after");                 return retValue;             }         });         Object proxy = enhancer.create();         Hi hi = (Hi) proxy;         hi.sayHi("LXY");         //可以把MethodInterceptor提取出来，单独写一个类，为了方便大家看，这里我用内部类的形式         class CGLibProxy implements MethodInterceptor {
              public 
    
      T getProxy(Class
     
       clazz){
                  return (T) Enhancer.create(clazz, this);             }             public Object intercept(Object target, Method method, Object[] args, MethodProxy proxy) throws Throwable {
                  before();                 Object result = proxy.invokeSuper(target, args);                 after();                 return result;             }             private void before(){
                  System.out.println("Before");             }             private void after(){
                  System.out.println("After");             }         }         CGLibProxy cgLibProxy = new CGLibProxy();         Hi hi2 = cgLibProxy.getProxy(Hi.class);         hi2.sayHi("LZHL");     } }