GlobalExceptionHandle全局异常处理器

当我们新增员工时输入的账户已经存在，由于employee表中对该字段加入唯一约束，此时程序会抛出异常:
Duplicate entry '123456' for key 'employee.idx_username'
此时需要我们的程序进行异常捕获，通常的处理方式有两种:
1,在Controller方法中加入try，catch进行捕获
2,使用异常处理器进行全局异常捕获


下面是使用异常类进行全局捕获


package com.itheima.reggie.common;

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestController;

import java.sql.SQLIntegrityConstraintViolationException;

@ControllerAdvice(annotations = {RestController.class,Controller.class})
@RestController
@Slf4j
public class GlobalExceptionHandle {


    @ExceptionHandler(SQLIntegrityConstraintViolationException.class)
     public R<String> exceptionHandler(SQLIntegrityConstraintViolationException ex){
        log.error(ex.getMessage());

      /* if (ex.getMessage().contains())*/

        if (ex.getMessage().contains("Duplicate entry")){
            String[] splite =ex.getMessage().split(" ");
            String msg =splite[2] + "已存在";

         return  R.error(msg);

        }

         return R.error("未知错误");

     }


}