Java动态代理的两种实现方式详解【附相关jar文件下载】

public interface UserService {
  public String getName(int id);
  public Integer getAge(int id);
}
public class UserServiceImpl implements UserService {
  @Override
  public String getName(int id) {
    System.out.println("------getName------");
    return "Tom";
  }
  @Override
  public Integer getAge(int id) {
    System.out.println("------getAge------");
    return 10;
  }
}

public class UserInvocationHandler implements InvocationHandler {
  private Object target;
  UserInvocationHandler() {
    super();
  }
  UserInvocationHandler(Object target) {
    super();
    this.target = target;
  }
  @Override
  public Object invoke(Object o, Method method, Object[] args) throws Throwable {
    if("getName".equals(method.getName())){
      System.out.println("++++++before " + method.getName() + "++++++");
      Object result = method.invoke(target, args);
      System.out.println("++++++after " + method.getName() + "++++++");
      return result;
    }else{
      Object result = method.invoke(target, args);
      return result;
    }
  }
}

public class M {
  public static void main(String[] args) {
    UserService userService = new UserServiceImpl();
    InvocationHandler invocationHandler = new UserInvocationHandler(userService);
    UserService userServiceProxy = (UserService) Proxy.newProxyInstance(
        userService.getClass().getClassLoader(),
        userService.getClass().getInterfaces(),
        invocationHandler);
    System.out.println(userServiceProxy.getName(1));
    System.out.println(userServiceProxy.getAge(1));
  }
}

public class CglibMethodInterceptor implements MethodInterceptor {
  @Override
  public Object intercept(Object o, Method method, Object[] args, MethodProxy methodProxy) throws Throwable {
    System.out.println("------before " + methodProxy.getSuperName() + "------");
    Object o1 = methodProxy.invokeSuper(o, args);
    System.out.println("------after " + methodProxy.getSuperName() + "------");
    return o1;
  }
}

public class M {
  public static void main(String[] args) {
    CglibMethodInterceptor cglibProxy = new CglibMethodInterceptor();
    Enhancer enhancer = new Enhancer();
    enhancer.setSuperclass(UserServiceImpl.class);
    enhancer.setCallback(cglibProxy);
    UserService o = (UserService) enhancer.create();
    o.getName(1);
    o.getAge(1);
  }
}