全局统一异常处理

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.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import java.sql.SQLIntegrityConstraintViolationException;

@ControllerAdvice(annotations = {RestController.class, Controller.class})//annotations注解的意思拦截添加了RestController
@ResponseBody
@Slf4j
public class GlobalExceptionHandler {
//    添加@ExceptionHandler注解，参数为要处理的哪个异常类，方法名任意
    @ExceptionHandler(SQLIntegrityConstraintViolationException.class)
    public R<String> exceptionHandler(SQLIntegrityConstraintViolationException ex){
        log.error(ex.getMessage());
//        异常信息中包含"Duplicate entry"这个关键字说明字段重复
        if(ex.getMessage().contains("Duplicate entry")){
            String[] split = ex.getMessage().split(" ");
            String name = split[2]+"已存在";
            return R.error("msg");
        }
        return R.error("未知错误");
    }
}