springboot全局异常捕捉及处理

        全部异常捕捉，省了每个controller里面try-catch，而且有些异常不一定在controller捕捉，而@RestControllerAdvice，就可以实现全局统一异常的捕捉和处理。以请求参数校验为例，为了校验请求参数是否符合指定的类型、格式、大小等，每个controller层都有类似下面这段代码：

参数校验不符合规范结果返回这段代码不能抛弃，返回前端的结果必须有标准的规范，因此做了这样的妥协。

{
  "code":"1",
  "msg":"success",
  "data":返回的数据
}

如果做了全局异常的捕捉和处理，代码更加整洁，而且省了很多不必要的异常处理

1、ParamExceptionConfig

package com.cn.dl.springbootdemo.config;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.validation.FieldError;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;

import java.util.List;

/**
 * Created by yanshao on 2019-11-06.
 */
@RestControllerAdvice
public class ParamExceptionConfig {
    private static final Logger logger = LoggerFactory.getLogger(ParamExceptionConfig.class);

    @ExceptionHandler(MethodArgumentNotValidException.class)
    public String methodArgumentNotValidHandler(MethodArgumentNotValidException exception) {
        logger.error("MethodArgumentNotValidHandler",exception);
        List<FieldError> fieldErrors = exception.getBindingResult().getFieldErrors();
        String msg = fieldErrors.stream().findFirst().map(error -> String.format("%s: %s", error.getField(), error.getDefaultMessage())).orElse(null);
        return ResResult.error(msg);
    }

    @ExceptionHandler(RuntimeException.class)
    public String handleRuntimeException(RuntimeException e) {
        logger.error("handleRuntimeException",e);
        return ResResult.error("系统异常");
    }

    @ExceptionHandler(Exception.class)
    public String handleException(Exception e) {
        logger.error("handleException",e);
        return ResResult.error("系统异常");
    }
}

2、ResResult：统一返回处理

package com.cn.dl.springbootdemo.config;

import com.alibaba.fastjson.JSONObject;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.io.Serializable;

/**
 * Created by yanshao on 2019-11-06.
 */
@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class ResResult implements Serializable {

    private static final long serialVersionUID = 4921061998653835814L;

    private static final String errorCode = "0";

    private static final String successCode = "1";

    private String code;

    private String msg;

    private Object data;

    public static String error(String msg){
       return JSONObject.toJSONString(ResResult.builder().code(errorCode).msg(msg).build());
    }

    public static String success(String msg,Object data){
        return JSONObject.toJSONString(ResResult.builder().code(successCode).msg(msg).data(data).build());
    }

}

3、ValidTestController：测试案例

package com.cn.dl.springbootdemo.controller;

import com.alibaba.fastjson.JSONObject;
import com.cn.dl.springbootdemo.config.ResResult;
import com.cn.dl.springbootdemo.request.UserOperatorRecordReq;
import org.springframework.util.CollectionUtils;
import org.springframework.validation.BindingResult;
import org.springframework.validation.FieldError;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.validation.Valid;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

/**
 * Created by yanshao on 2019-11-05.
 */
@RestController
@RequestMapping("/user/test")
public class ValidTestController {

    @PostMapping("getRecord")
    public String getUserOperatorRecord(@RequestBody @Valid UserOperatorRecordReq recordReq){
        int i = 0,num = 2;
        List<JSONObject> resultList = new ArrayList<>();
        while (i < num){
            JSONObject json = new JSONObject();
            json.put("date",new Date());
            json.put("operatorType","create");
            i ++;
            resultList.add(json);
        }
        return ResResult.success("success",resultList);
    }

    @PostMapping("getRecordOne")
    public String getUserOperatorRecordOne(@RequestBody @Valid UserOperatorRecordReq recordReq, BindingResult bindingResult){
        List<FieldError> fieldErrors = bindingResult.getFieldErrors();
        if(! CollectionUtils.isEmpty(fieldErrors)){
            String msg = fieldErrors.stream().findFirst().map(error -> String.format("%s: %s", error.getField(), error.getDefaultMessage())).orElse(null);
            System.out.println("msg>>>" + msg);
            return ResResult.error(msg);
        }
        int i = 0,num = 2;
        List<JSONObject> resultList = new ArrayList<>();
        while (i < num){
            JSONObject json = new JSONObject();
            json.put("date",new Date());
            json.put("operatorType","create");
            i ++;
            resultList.add(json);
        }
        return ResResult.success("success",resultList);
    }


}