SpringBoot如何设置404、500返回统一格式json

# 自定义
#出现错误时, 直接抛出异常
spring.mvc.throw-exception-if-no-handler-found=true
#不要为我们工程中的资源文件建立映射
spring.web.resources.add-mappings=false

package com.qykhhr.dujiaoshouservice.exceptionhandler;

import com.qykhhr.dujiaoshouservice.util.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;

import java.sql.SQLIntegrityConstraintViolationException;

/**
 * 异常处理机制
 * 先找到特定异常处理机制，如果没有就会调用Exception异常处理机制
 */
@ControllerAdvice
@Slf4j
public class GlobalExceptionHandler {

    /**
     * 指定出现什么异常来执行这个方法
     * @param e
     * @return
     */
    @ExceptionHandler(Exception.class)
    @ResponseBody
    public R error(Exception e){
        e.printStackTrace();
        if (e instanceof SQLIntegrityConstraintViolationException){
            return R.error().message("数据库主键冲突，如是本人，请联系管理员");
        }else if (e instanceof org.springframework.web.servlet.NoHandlerFoundException){
            return R.error().message("找不到资源，/(ㄒoㄒ)/~~");
        }
        return R.error().message("内部服务器错误，/(ㄒoㄒ)/~~!");
    }

    /**
     * 自定义异常处理
     * @param e
     * @return
     */
    @ExceptionHandler(DujiaoshouException.class)
    @ResponseBody
    public R error(DujiaoshouException e){
        log.error(e.getMessage());
        e.printStackTrace();
        return R.error().code(e.getCode()).message(e.getMsg());
    }
}

package com.qykhhr.dujiaoshouservice.util;

import lombok.Data;

import java.util.HashMap;
import java.util.Map;

/**
 * 统一返回结果的类
 * @author 雨林
 */
@Data
public class R {

    private Boolean success;
    private Integer code;
    private String message;
    private Map<String,Object> data = new HashMap<>();

    // 把构造方法私有化，只能使用提供的静态方法
    private R(){

    }

    // 成功静态方法
    public static R ok(){
        R r = new R();

        r.setSuccess(true);
        r.setCode(ResultCode.SUCCESS);
        r.setMessage("成功");
        return r;
    }

    // 失败静态方法
    public static R error(){
        R r = new R();

        r.setSuccess(false);
        r.setCode(ResultCode.ERROR);
        r.setMessage("失败");
        return r;
    }

    public R message(String message){
        this.setMessage(message);
        return this;
    }

    public R code(Integer code){
        this.setCode(code);
        return this;
    }

    public R data(Map<String, Object> map){
        this.setData(map);
        return this;
    }

    public R data(String key, Object value){
        this.data.put(key, value);
        return this;
    }
}

upload.image.path=/util/images/
upload.apk.path=/util/apk/
upload.crash.exception.file.path=/util/crash/

/**
 * 资源映射路径，只能配置一个映射
 */
@Configuration
public class MyWebMvcConfigurer extends WebMvcConfigurerAdapter {
    @Value("${upload.file.path}")
    private String uploadPath;

    @Value("${upload.image.path}")
    private String uploadImagePath;

    @Value("${upload.crash.exception.file.path}")
    private String uploadCrashExceptionFilePath;

    @Value("${upload.apk.path}")
    private String uploadApkPath;

    /**
     * 将D:\\upload下的文件映射到当前项目/upload/下
     * @param registry
     */
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {

        registry.addResourceHandler("/favicon.ico").addResourceLocations("classpath:/static/");

        //addResourceHandler()里配置需要映射的文件夹，此处代表映射文件夹user下的所有资源。
        //addResourceLocations()配置文件夹在系统中的路径，使用绝对路径，格式为“file:你的路径/” 后面的 / 必须加上，否则映射失效
//        registry.addResourceHandler("/upload/**").addResourceLocations("file:D:/dujiaoshouapp/");
//        registry.addResourceHandler("/upload/**").addResourceLocations("file:"+uploadPath);
        registry.addResourceHandler("/upload/images/**").addResourceLocations("file:"+uploadImagePath);
        registry.addResourceHandler("/upload/crash/**").addResourceLocations("file:"+uploadCrashExceptionFilePath);
        registry.addResourceHandler("/upload/apk/**").addResourceLocations("file:"+uploadApkPath);
    }
}

@Component
public class ExceptionInterceptor implements HandlerInterceptor {

    @Autowired
    private RedisTemplate redisTemplate;


    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        if (modelAndView != null){
            // 防止出现空指针
            // 请求转到 / 
            modelAndView.setViewName("/");
        }
    }
}

@Configuration
public class MyWebMvcConfigurer extends WebMvcConfigurerAdapter {
    @Autowired
    private ExceptionInterceptor exceptionInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(exceptionInterceptor);
        super.addInterceptors(registry);
    }

package com.qykhhr.dujiaoshouservice.controller;

import com.qykhhr.dujiaoshouservice.util.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@Slf4j
public class ExceptionController {

    @RequestMapping("/")
    public R error() {
        log.info("处理 /error 请求");
        return R.error().message("访问资源无效！");
    }
}