共两种
- 实现接口
- 使用注解(简单)
最近做项目在通过异常控制返回值code码,初步思路是定义一个全局异常处理器,上面刚说到有两种方法,先讲第一种.
HandlerExceptionResolver
springmvc给我们提供了可以扩展的接口HandlerExceptionResolver,实现此接口,重写处理异常方法.此方法有些不好用的是在返回值上面.强制我们返回model and view,如果想要返回json,则还需要自己转换一层,下文写到了.
/*
* Copyright 2002-2018 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.web.servlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.lang.Nullable;
/**
* Interface to be implemented by objects that can resolve exceptions thrown during
* handler mapping or execution, in the typical case to error views. Implementors are
* typically registered as beans in the application context.
*
* <p>Error views are analogous to JSP error pages but can be used with any kind of
* exception including any checked exception, with potentially fine-grained mappings for
* specific handlers.
*
* @author Juergen Hoeller
* @since 22.11.2003
*/
public interface HandlerExceptionResolver {
/**
* Try to resolve the given exception that got thrown during handler execution,
* returning a {@link ModelAndView} that represents a specific error page if appropriate.
* <p>The returned {@code ModelAndView} may be {@linkplain ModelAndView#isEmpty() empty}
* to indicate that the exception has been resolved successfully but that no view
* should be rendered, for instance by setting a status code.
* @param request current HTTP request
* @param response current HTTP response
* @param handler the executed handler, or {@code null} if none chosen at the
* time of the exception (for example, if multipart resolution failed)
* @param ex the exception that got thrown during handler execution
* @return a corresponding {@code ModelAndView} to forward to,
* or {@code null} for default processing in the resolution chain
*/
@Nullable
ModelAndView resolveException(
HttpServletRequest request, HttpServletResponse response, @Nullable Object handler, Exception ex);
}
如果model and view要转换成普通json返回,则需要手动转换一层:
MappingJackson2JsonView jackson2JsonView = new MappingJackson2JsonView();
//设置返回的json map
Map returnData = Maps.newHashMap();
//TODO add return data
jackson2JsonView.setAttributesMap(returnData);
ModelAndView view = new ModelAndView();
view.setView(jackson2JsonView);
return view;
简单方法(使用注解)
在开始说这个之前,我们要先了解一下相关的两个注解
- @ControllerAdvice,注释大致意思就是 controllerAdvice是一个用于定义@ExceptionHadnler的Component注解.适用于所有的@RequestMapping方法
- @ExceptionHandler:需要处理的异常,如果不传值默认处理所有异常
使用方法:
import com.immomo.moaservice.live.assess.impl.exception.ActivityAnalyticsException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestControllerAdvice;
/**
* @author: hman
* @date 2018-11-05
* @desc: 全局异常处理
*/
@RestControllerAdvice
public class ActivityExceptionHandler {
@ExceptionHandler(ActivityAnalyticsException.class)
@ResponseBody
public ResultUtil resolveException(ActivityAnalyticsException e) {
return ResultUtil.build(e.getCodeEnum());
}
}
