从零搭建自己的SpringBoot后台框架(五)

Hello大家好，本章我们添加全局异常处理。有问题可以联系我mr_beany@163.com。另求各路大神指点，感谢

一：为什么需要定义全局异常

在互联网时代，我们所开发的应用大多是直面用户的，程序中的任何一点小疏忽都可能导致用户的流失，而程序出现异常往往又是不可避免的，所以我们需要对异常进行捕获，然后给予相应的处理，来减少程序异常对用户体验的影响

二：添加业务类异常

在前面说过的ret文件夹下创建ServiceException

package com.example.demo.core.ret;

import java.io.Serializable;

/**
 * @Description: 业务类异常
 * @author 张瑶
 * @date 2018/4/20 14:30
 * 
 */
public class ServiceException extends RuntimeException implements Serializable{

   private static final long serialVersionUID = 1213855733833039552L;

   public ServiceException() {
   }

   public ServiceException(String message) {
      super(message);
   }

   public ServiceException(String message, Throwable cause) {
      super(message, cause);
   }
}

三：添加异常处理配置

打开上篇文章创建的WebConfigurer，添加如下方法

@Override
public void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> exceptionResolvers) {
    exceptionResolvers.add(getHandlerExceptionResolver());
}

/**
 * 创建异常处理
 * @return
 */
private HandlerExceptionResolver getHandlerExceptionResolver(){
    HandlerExceptionResolver handlerExceptionResolver = new HandlerExceptionResolver(){
        @Override
        public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response,
                                             Object handler, Exception e) {
            RetResult<Object> result = getResuleByHeandleException(request, handler, e);
            responseResult(response, result);
            return new ModelAndView();
        }
    };
    return handlerExceptionResolver;
}

/**
 * 根据异常类型确定返回数据
 * @param request
 * @param handler
 * @param e
 * @return
 */
private RetResult<Object> getResuleByHeandleException(HttpServletRequest request, Object handler, Exception e){
    RetResult<Object> result = new RetResult<>();
    if (e instanceof ServiceException) {
        result.setCode(RetCode.FAIL).setMsg(e.getMessage()).setData(null);
        return result;
    }
    if (e instanceof NoHandlerFoundException) {
        result.setCode(RetCode.NOT_FOUND).setMsg("接口 [" + request.getRequestURI() + "] 不存在");
        return result;
    }
    result.setCode(RetCode.INTERNAL_SERVER_ERROR).setMsg("接口 [" + request.getRequestURI() + "] 内部错误，请联系管理员");
    String message;
    if (handler instanceof HandlerMethod) {
        HandlerMethod handlerMethod = (HandlerMethod) handler;
        message = String.format("接口 [%s] 出现异常，方法：%s.%s，异常摘要：%s", request.getRequestURI(),
                handlerMethod.getBean().getClass().getName(), handlerMethod.getMethod() .getName(), e.getMessage());
    } else {
        message = e.getMessage();
    }
    LOGGER.error(message, e);
    return result;
}

/**
 * @Title: responseResult
 * @Description: 响应结果
 * @param response
 * @param result
 * @Reutrn void
 */
private void responseResult(HttpServletResponse response, RetResult<Object> result) {
    response.setCharacterEncoding("UTF-8");
    response.setHeader("Content-type", "application/json;charset=UTF-8");
    response.setStatus(200);
    try {
        response.getWriter().write(JSON.toJSONString(result,SerializerFeature.WriteMapNullValue));
    } catch (IOException ex) {
        LOGGER.error(ex.getMessage());
    }
}

四：创建测试接口

package com.example.demo.service.impl;

import com.example.demo.core.ret.ServiceException;
import com.example.demo.dao.UserInfoMapper;
import com.example.demo.model.UserInfo;
import com.example.demo.service.UserInfoService;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.List;

/**
 * @author 张瑶
 * @Description:
 * @time 2018/4/18 11:56
 */
@Service
public class UserInfoServiceImpl implements UserInfoService{

    @Resource
    private UserInfoMapper userInfoMapper;

    @Override
    public UserInfo selectById(Integer id){
        UserInfo userInfo = userInfoMapper.selectById(id);
        if(userInfo == null){
            throw new ServiceException("暂无该用户");
        }
        return userInfo;
    }
}

UserInfoController.java

package com.example.demo.controller;

import com.example.demo.core.ret.RetResponse;
import com.example.demo.core.ret.RetResult;
import com.example.demo.core.ret.ServiceException;
import com.example.demo.model.UserInfo;
import com.example.demo.service.UserInfoService;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;
import java.util.List;

/**
 * @author 张瑶
 * @Description:
 * @time 2018/4/18 11:39
 */
@RestController
@RequestMapping("userInfo")
public class UserInfoController {

    @Resource
    private UserInfoService userInfoService;

    @PostMapping("/hello")
    public String hello(){
        return "hello SpringBoot";
    }

    @PostMapping("/selectById")
    public RetResult<UserInfo> selectById(Integer id){
        UserInfo userInfo = userInfoService.selectById(id);
        return RetResponse.makeOKRsp(userInfo);
    }

    @PostMapping("/testException")
    public RetResult<UserInfo> testException(Integer id){
        List a = null;
        a.size();
        UserInfo userInfo = userInfoService.selectById(id);
        return RetResponse.makeOKRsp(userInfo);
    }


}

五：接口测试

访问 192.168.1.104:8080/userInfo/selectById 参数 id:3

{
    "code": 400,
    "data": null,
    "msg": "暂无该用户"
}

访问 192.168.1.104:8080/userInfo/testException

{
    "code": 500,
    "data": null,
    "msg": "接口 [/userInfo/testException] 内部错误，请联系管理员"
}

项目地址

gitee.com/beany/mySpr…

写文章不易，如对您有帮助，请帮忙点下star

结尾

springboot添加全局异常处理已完成，后续功能接下来陆续更新，有问题可以联系我mr_beany@163.com。另求各路大神指点，感谢大家。