spring boot整合全局异常处理

• 全局异常处理
  @ControllerAdvice 只能处理controller层异常和service抛到controller层未处理的异常
@ControllerAdvice:生命这个类是异常处理类，交给spring容器管理
@ExceptionHandler:指明处理那个异常类
• 理解：好像一个触发器，运行抛出未处理的异常，就会触发这个类

package com.gzhj.safecampus.configuration.exceptionhandler;

import com.baomidou.mybatisplus.core.exceptions.MybatisPlusException;
import com.gzhj.core.exception.BusinessException;
import com.gzhj.core.restsupport.ResponseResult;
import com.gzhj.core.restsupport.ResponseStatuses;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;

import javax.validation.ConstraintViolation;
import javax.validation.ConstraintViolationException;
import java.util.List;
import java.util.stream.Collectors;

/**
 * 全局异常处理类
 *
 * @author Jack
 */
@ControllerAdvice
public class GlobalExceptionHandler {

    private static final Logger log = LoggerFactory.getLogger(GlobalExceptionHandler.class);

    /**
     * 业务异常处理
     *
     * @param exception
     * @return
     */
    @ExceptionHandler(BusinessException.class)
    @ResponseBody
    public ResponseResult businessExceptionHandler(BusinessException exception) {

        // 记录到日志文件
        log.error(exception.getMessage(), exception);

        return ResponseResult.error(exception.getErrorCode(), exception.getMessage());
    }

    /**
     * nullpointer exception处理
     *
     * @param exception
     * @return
     */
    @ExceptionHandler(NullPointerException.class)
    @ResponseBody
    public ResponseResult nullPointExceptionHandler(NullPointerException exception) {
        String errMsg = "未将对象引用设置到对象实例，请检查代码！";

        // 记录到日志文件
        log.error(errMsg, exception);

        return ResponseResult.error(ResponseStatuses.ERROR_BUSINESS_COMMON.getCode(), errMsg);
    }

    /**
     * Mybatis plus Exception异常处理
     *
     * @param exception
     * @return
     */
    @ExceptionHandler(MybatisPlusException.class)
    @ResponseBody
    public ResponseResult mybatisplusExceptionHandler(MybatisPlusException exception) {
        // 记录到日志文件
        log.error("Mybatis plus数据操作出现异常", exception);

        return ResponseResult.error(ResponseStatuses.ERROR_BUSINESS_COMMON.getCode(), exception.getMessage());
    }

    /**
     * 校验异常处理
     *
     * @return
     * @valid验证异常处理
     */
    @ExceptionHandler(value = ConstraintViolationException.class)
    @ResponseBody
    public ResponseResult ConstraintViolationExceptionHandler(ConstraintViolationException exception) {

        // 记录到日志文件
        log.error(exception.getMessage(), exception);

        List<String> msgList = exception.getConstraintViolations()
                .stream()
                .map(ConstraintViolation::getMessage)
                .collect(Collectors.toList());

        return ResponseResult.error(ResponseStatuses.ERROR_BUSINESS_COMMON.getCode(), msgList.toString());
    }

    /**
     * 将Exception信息转为String
     *
     * @param e 异常
     * @return 异常字符串
     */
    private String getExceptionDetailMessage(Exception e) {
        StackTraceElement[] ste = e.getStackTrace();
        StringBuffer sb = new StringBuffer();
        sb.append(e.getMessage() + "\r\n");

        for (int i = 0; i < ste.length; i++) {
            sb.append(ste[i].toString() + "\r\n");
        }

        return sb.toString();
    }
}