Java动态代理与静态代理以及它能为我们做什么

 1 public class ProductAuditCallbackServiceProxy implements ProductAuditCallbackService {
 2 
 3     @Resource
 4     private ProductAuditCallbackService productAuditCallbackService;
 5 
 6     @Override
 7     public Result<Void> auditProduct(ProductAuditRequest request, String auditStatus) {
 8         if (auditStatus == "DELETED") {
 9             return new Result<>();
10         }
11         return productAuditCallbackService.auditProduct(request, auditStatus);
12     }
13 
14 
15 ...
16 }

 1 package java.lang.reflect;
 2 
 3 /**
 4  * {@code InvocationHandler} is the interface implemented by
 5  * the <i>invocation handler</i> of a proxy instance.
 6  *
 7  * <p>Each proxy instance has an associated invocation handler.
 8  * When a method is invoked on a proxy instance, the method
 9  * invocation is encoded and dispatched to the {@code invoke}
10  * method of its invocation handler.
11  *
12  * @author      Peter Jones
13  * @see         Proxy
14  * @since       1.3
15  */
16 public interface InvocationHandler {
17 
18     public Object invoke(Object proxy, Method method, Object[] args)
19         throws Throwable;
20 }

 1 public class MethodInvocationHandler implements InvocationHandler {
 2 
 3     //被代理对象
 4     private Object business;
 5 
 6     private final MethodMonitor methodMonitor;
 7 
 8     public MethodInvocationHandler(MethodMonitor methodMonitor) {
 9         this.methodMonitor = methodMonitor;
10     }
11 
12     /**
13      * 代理方法
14      */
15     @Override
16     public Object invoke(Object proxy, Method method, Object[] args)
17             throws Throwable {
18 
19         long startTime = System.currentTimeMillis();
20 
21         Object result = method.invoke(this.business, args);
22 
23         //方法调用统计
24         this.methodMonitor.methodCount(this.business.getClass().getSimpleName() + POINT + method.getName(), startTime);
25         return result;
26     }
27 
28 }

 1 public class Business {
 2 
 3     public void createJob() {
 4         System.out.println("test createJob");
 5     }
 6 
 7 
 8     public void processJob() {
 9         System.out.println("test processJob");
10     }
11 
12     public void closeJob() {
13         System.out.println("test closeJob");
14     }
15 
16 }
17 
18 
19 
20 public class MethodSampleClient {
21 
22     private Business business;
23 
24     @Getter
25     private Object proxy;
26 
27     private InvocationHandler invocationHandler;
28 
29 
30     public void init() {
31         this.business = new Business();
32         this.invocationHandler = new MethodInvocationHandler(new MethodMonitor());
33         this.proxy = bind(this.business, invocationHandler);
34     }
35 
36     /**
37      * 绑定对象, 直接初始化并返回代理类供客户端使用
38      */
39     public Object bind(Object business, InvocationHandler invocationHandler) {
40         return Proxy.newProxyInstance(
41                 //被代理类的ClassLoader
42                 business.getClass().getClassLoader(),
43                 //要被代理的接口,本方法返回对象会自动声称实现了这些接口
44                 business.getClass().getInterfaces(),
45                 //代理处理器对象
46                 invocationHandler);
47     }
48     
49 }    
50 
51 
52 /**
53 *  A simple client test class
54 */
55 public class Test {
56 
57     public void main(String[] args) {
58         MethodSampleClient methodSampleClient = new MethodSampleClient();
59         methodSampleClient.init();
60 
61         methodSampleClient.getProxy().createJob();
62         methodSampleClient.getProxy().processJob();
63         methodSampleClient.getProxy().closeJob();
64     }
65 
66 }