public class MyInterceptor implements HandlerInterceptor{
//在请求处理之前进行调用（Controller方法调用之前
@Override
public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
System.out.printf(“preHandle被调用\n”);
return true;
}

//请求处理之后进行调用，但是在视图被渲染之前（Controller方法调用之后）
@Override
public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
    System.out.println("postHandle被调用\n");
}

//在整个请求结束之后被调用，也就是在DispatcherServlet 渲染了对应的视图之后执行（主要是用于进行资源清理工作）
@Override
public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
    System.out.println("afterCompletion被调用\n");
}

}