Mybatis中拦截器的简单实现方法

//服务员的接口
public interface Waiter {
  void serve();
}
//服务员的实现
public class WaiterImpl implements Waiter {
  @Override
  public void serve() {
    System.out.println("服务中...");
  }
}
//需要代理的对象处理器
class WaitInvocationHandler implements InvocationHandler {
  private Waiter waiter;

  public WaitInvocationHandler(Waiter waiter1) {
    waiter = waiter1;
  }

  @Override
  public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
    System.out.println("你好");
    Object invoke = method.invoke(waiter, args);
    System.out.println("再见");
    return invoke;
  }
}
public class App {
  //普通的实现
  @Test
  public void fun() {
    Waiter waiter = new WaiterImpl();
    waiter.serve();
  }

  @Test
  public void fun1() {
    Waiter a = new WaiterImpl();
    ClassLoader classLoader = getClass().getClassLoader();
    Class[] classes = {Waiter.class};
    //生成代理对象
    Waiter waiterproxy = (Waiter) Proxy.newProxyInstance(classLoader, classes, new WaitInvocationHandler(a));
    waiterproxy.serve();
  }
}

//拦截器 V1 版本
public interface MyInterceptorV1 {
  void interceptor();
}
//代理对象变成这个
public class TargetProxyV1 implements InvocationHandler {

  private Target target;

  private MyInterceptorV1 myInterceptor;

  public TargetProxyV1(Target target, MyInterceptorV1 myInterceptor) {
    this.target = target;
    this.myInterceptor = myInterceptor;
  }

  @Override
  public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
    myInterceptor.interceptor();
    return method.invoke(target, args);
  }
}

public interface MyInterceptorV1 {
  void interceptor(Method method, Object[] args);
}

@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
  myInterceptor.interceptor(method, args);
  return method.invoke(target, args);
}

@Getter
@Setter
@AllArgsConstructor
public class MyInvocation {
  private Object target;
  private Method method;
  private Object[] args;

  public Object proceed() throws InvocationTargetException, IllegalAccessException {
    return method.invoke(target, args);
  }
}
//没错这就是 V2 版本
public interface MyInterceptorV2 {
  Object interceptor(MyInvocation invocation) throws Throwable;
}