SpringMVC实现全局异常处理

package cn.znx.blog.exception;

import com.google.gson.Gson;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.HashMap;
import java.util.Map;

public class MyExceptionResolver implements HandlerExceptionResolver {

    public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler,
                                         Exception exception) {
        //打印错误信息
        exception.printStackTrace();
        //定义错误信息
        String message = "系统繁忙，请稍后重试！";
        if(exception instanceof MyException){
            message = ((MyException)exception).getMessage();
        }
        //判断请求类型
        HandlerMethod handlerMethod = (HandlerMethod) handler;
        ResponseBody responseBody = handlerMethod.getMethod().getAnnotation(ResponseBody.class);
        //如果是json请求，则返回json数据
        if(responseBody!=null){
            Map<String,Object> responseMap = new HashMap<String,Object>();
            responseMap.put("code", "999999");
            responseMap.put("message", message);
            String json = new Gson().toJson(responseMap);
            response.setCharacterEncoding("UTF-8");
            response.setContentType("application/json;charset=utf-8");
            try {
                response.getWriter().write(json);
                response.getWriter().flush();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return new ModelAndView();
        }
        //如果是跳转页面的请求
        //页面转发
        ModelAndView modelAndView = new ModelAndView();
        //将错误信息传到页面
        modelAndView.addObject("message", message);
        //指向错误页面
        modelAndView.setViewName("error");
        return modelAndView;
    }

}

@Data
public class Result {

    //状态码
    private String code;

    //错误信息
    private String message;
    //还是json
    private HashMap<String,Object> data = new HashMap<>();

    //登录失败
    public static Result error(String string){

        Result result = new Result();
        result.setCode("999999");
        if (StringUtils.isEmpty(string)){
            result.setMessage("登录失败");
        }else{
            result.setMessage(string);
        }
        return result;
    }

    //添加数据
    public Result add(String key,Object value){
        this.getData().put(key,value);

        return this;
    }

    //登录成功
    public static Result success(){
        Result result = new Result();
        result.setCode("000000");
        result.setMessage("登录成功");
        return result;
    }
    
}