java使用动态代理来实现AOP（日志记录）

 1 /
 2   Created with IntelliJ IDEA.
 3   Author: wangjie  email:tiantian.china.2@gmail.com
 4   Date: 13-9-23
 5   Time: 下午3:49
 6  */
 7 public interface BussinessService {
 8     public String login(String username, String password);
 9     public String find();
10 }
11
12 public class BussinessServiceImpl implements BussinessService {
13     private Logger logger = Logger.getLogger(this.getClass().getSimpleName());
14
15     @Override
16     public String login(String username, String password) {
17         return “login success”;
18     }
19
20     @Override
21     public String find() {
22         return “find success”;
23     }
24
25 }

 1 /
 2   Created with IntelliJ IDEA.
 3   Author: wangjie  email:tiantian.china.2@gmail.com
 4   Date: 13-9-24
 5   Time: 上午10:27
 6  */
 7 public interface WorkService {
 8     public String work();
 9     public String sleep();
10 }
11
12 public class WorkServiceImpl implements WorkService{
13     @Override
14     public String work() {
15         return “work success”;
16     }
17
18     @Override
19     public String sleep() {
20         return “sleep success”;
21     }
22 }

 1 package com.wangjie.aoptest2.invohandler;
 2
 3 import java.lang.reflect.InvocationHandler;
 4 import java.lang.reflect.Method;
 5 import java.lang.reflect.Proxy;
 6 import java.util.Arrays;
 7 import java.util.HashMap;
 8 import java.util.logging.Logger;
 9
10 /
11   Created with IntelliJ IDEA.
12   Author: wangjie  email:tiantian.china.2@gmail.com
13   Date: 13-9-23
14   Time: 下午3:47
15  */
16 public class LogInvoHandler implements InvocationHandler{
17     private Logger logger = Logger.getLogger(this.getClass().getSimpleName());
18
19     private Object target; // 代理目标
20     private Object proxy; // 代理对象
21
22     private static HashMap<Class<?>, LogInvoHandler> invoHandlers = new HashMap<Class<?>, LogInvoHandler>();
23
24     private LogInvoHandler() {
25     }
26
27     /
28       通过Class来生成动态代理对象Proxy
29       @param clazz
30       @return
31      /
32     public synchronized static<T> T getProxyInstance(Class<T> clazz){
33         LogInvoHandler invoHandler = invoHandlers.get(clazz);
34
35         if(null == invoHandler){
36             invoHandler = new LogInvoHandler();
37             try {
38                 T tar = clazz.newInstance();
39                 invoHandler.setTarget(tar);
40                 invoHandler.setProxy(Proxy.newProxyInstance(tar.getClass().getClassLoader(),
41                         tar.getClass().getInterfaces(), invoHandler));
42             } catch (Exception e) {
43                 e.printStackTrace();
44             }
45             invoHandlers.put(clazz, invoHandler);
46
47         }
48
49         return (T)invoHandler.getProxy();
50     }
51
52     @Override
53     public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
54
55         Object result = method.invoke(target, args); // 执行业务处理
56
57         // 打印日志
58         logger.info(“____invoke method: “ + method.getName()
59                     + “; args: “ + (null == args ? “null” : Arrays.asList(args).toString())
60                     + “; return: “ + result);
61
62
63         return result;
64     }
65
66     public Object getTarget() {
67         return target;
68     }
69
70     public void setTarget(Object target) {
71         this.target = target;
72     }
73
74     public Object getProxy() {
75         return proxy;
76     }
77
78     public void setProxy(Object proxy) {
79         this.proxy = proxy;
80     }
81 }

 1 /*
 2   Created with IntelliJ IDEA.
 3   Author: wangjie  email:tiantian.china.2@gmail.com
 4   Date: 13-9-24
 5   Time: 上午9:54
 6  /
 7 public class Test {
 8     public static Logger logger = Logger.getLogger(Test.class.getSimpleName());
 9     public static void main(String[] args) {
10
11         BussinessService bs = LogInvoHandler.getProxyInstance(BussinessServiceImpl.class);
12         bs.login(“zhangsan”, “123456”);
13         bs.find();
14
15         logger.info(“————————————–”);
16
17         WorkService ws = LogInvoHandler.getProxyInstance(WorkServiceImpl.class);
18         ws.work();
19         ws.sleep();
20
21         logger.info(“————————————–”);
22
23         BussinessService bss = LogInvoHandler.getProxyInstance(BussinessServiceImpl.class);
24         bss.login(“lisi”, “654321”);
25         bss.find();
26
27     }
28 }