SpringBoot处理全局统一异常

在后端发生异常或者是请求出错时，前端通常显示如下

Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.

Fri Jun 07 15:38:07 CST 2019
There was an unexpected error (type=Not Found, status=404).
No message available

对于用户来说非常不友好。

本文主要讲解如何在SpringBoot应用中使用统一异常处理。

实现方式

第一种：使用@ControllerAdvice和@ExceptionHandler注解

第二种: 使用ErrorController类来实现。

第一种：使用@RestControllerAdvice和@ExceptionHandler注解

package com.itheima.reggie.exception;

import com.itheima.reggie.common.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.RequestBody;
import org.springframework.web.bind.annotation.RestControllerAdvice;

import javax.servlet.http.HttpServletResponse;
import java.sql.SQLIntegrityConstraintViolationException;

@Slf4j
@RestControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler(value = SQLIntegrityConstraintViolationException.class)
    public R sQLIntegrityConstraintViolationException(HttpServletResponse response, SQLIntegrityConstraintViolationException sqlException){
        log.info("SQLIntegrityConstraintViolationException...");
        log.info("错误代码："  + response.getStatus());
        return R.error(sqlException.getMessage());
    }

    @ExceptionHandler(value = NullPointerException.class)
    public R globalException(HttpServletResponse response, NullPointerException exception){
        log.info("GlobalExceptionHandler...");
        log.info("错误代码："  + response.getStatus());
        return R.error(exception.getMessage());
    }


}

自定义异常处理

自定义一个异常

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.experimental.Accessors;

@Data
@AllArgsConstructor
@Accessors(chain = true)
public class ServiceException extends RuntimeException {
    /**
     * 错误码
     */
    protected Integer errorCode;
    /**
     * 错误信息
     */
    protected String errorMsg;
}

显而易见，这个异常继承了RuntimeException，属于运行时异常。
定义过之后，我们就可以和之前处理NullException方式一样处理我们自定义的异常。包括处理其他异常，都是这种方式。直接贴代码。

package com.itheima.reggie.exception;

import com.itheima.reggie.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;

import javax.servlet.http.HttpServletResponse;
import java.sql.SQLIntegrityConstraintViolationException;

@Slf4j
@RestControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler(value = SQLIntegrityConstraintViolationException.class)
    public R sQLIntegrityConstraintViolationException(HttpServletResponse response, SQLIntegrityConstraintViolationException sqlException){
        log.info("SQLIntegrityConstraintViolationException...");
        log.info("错误代码："  + response.getStatus());
        return R.error(sqlException.getMessage());
    }

    @ExceptionHandler(value = NullPointerException.class)
    public R globalException(HttpServletResponse response, NullPointerException exception){
        log.info("GlobalExceptionHandler...");
        log.info("错误代码："  + response.getStatus());
        return R.error(exception.getMessage());
    }

    /**
     * 处理自定义的业务异常
     * @param response
     * @param exception
     * @return
     */
    @ExceptionHandler(value = ServiceException.class)
    public R bizExceptionHandler(HttpServletResponse response, ServiceException exception){
        log.error("发生业务异常！原因是：{}", exception.getErrorMsg());
        return R.error(exception.getErrorMsg());
    }


}