JDK動態代理和CGLIB動態代理

阿新 • • 發佈：2020-09-12

JDK動態代理實現

被代理類（需實現介面）

 1 public class UserServiceImp implements UserService{
 2     @Override
 3     public void doService() {
 4         System.out.println(this.getClass() + "doService");
 5         try {
 6             Thread.sleep(2000);
 7         } catch (InterruptedException e) {
 8             e.printStackTrace();
 
 9         }
10     }
11 }

擴充套件類

 1 public class LogHandler implements InvocationHandler {
 2 
 3     Object target;
 4 
 5     public LogHandler(Object target) {
 6         this.target = target;
 7     }
 8 
 9     @Override
10     public Object invoke(Object proxy, Method method, Object[] args) throws 
 Throwable { // 重寫invoke方法
11         before();
12         method.invoke(target, args);
13         after();
14         return null;
15     }
16     public void before() {
17         System.out.println("日誌開始" + new Date(System.currentTimeMillis()));
18     }
19     public void after() {
20         System.out.println("日誌結束" + new 
 Date(System.currentTimeMillis()));
21     }
22 }

測試

 1 public class Test {
 2     public static void main(String[] args) {
 3         System.getProperties().setProperty("sun.misc.ProxyGenerator.saveGeneratedFiles", "true");
 4         UserServiceImp userService = new UserServiceImp(); // 建立被代理類物件
 5         LogHandler logHandler = new LogHandler(userService); // 建立擴充套件類物件，傳入被代理類物件
 6         ClassLoader classLoader = userService.getClass().getClassLoader(); // 獲取類載入器
 7         Class[] interfaces = userService.getClass().getInterfaces(); // 獲取所有介面
 8         UserService proxy = (UserService) Proxy.newProxyInstance(classLoader, interfaces, logHandler); // 建立代理物件
 9         proxy.doService();
10     }
11 }

CGLIB動態代理實現

被代理類

 1 public class MyService {
 2 
 3     public void doService() {
 4         System.out.println(this.getClass() + "doService");
 5         try {
 6             Thread.sleep(2000);
 7         } catch (InterruptedException e) {
 8             e.printStackTrace();
 9         }
10     }
11 }

擴充套件類

 1 public class LogHandler implements MethodInterceptor {
 2     @Override
 3     public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
 4         before();
 5         methodProxy.invokeSuper(o, objects);
 6         after();
 7         return null;
 8     }
 9     public void before() {
10         System.out.println("日誌開始" + new Date(System.currentTimeMillis()));
11     }
12     public void after() {
13         System.out.println("日誌結束" + new Date(System.currentTimeMillis()));
14     }
15 }

測試

1 public class Test {
2     public static void main(String[] args) {
3         Enhancer enhancer = new Enhancer();
4         enhancer.setSuperclass(MyService.class);
5         enhancer.setCallback(new LogHandler());
6         MyService myService = (MyService)enhancer.create();
7         myService.doService();
8     }
9 }