如何使用 @NotNull等注解校验 并全局异常处理

@NotNul 等注解的使用

代码：码云
1、添加依赖

        <!-- validation组件 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-validation</artifactId>
        </dependency>

2、在 controller 请求参数前 + @Vaild

    @RequestMapping("/doLogin")
    @ResponseBody
    public RespBean doLogin(@Valid LoginRequestParam param){}

3、在参数实体类上 加注解

@Data
public class LoginRequestParam {

    @NotBlank(message = "mobile不能为空")
    @IsMobile
    private String mobile;

    @NotBlank(message = "password不能为空")
    @Length(min = 32,message = "password 长度不对")
    private String password;

}

---

此时 的异常不会在页面显示 而是会 报400错误，并在 后台打印出错误，这就需要对异常进行拦截

后台保错信息，可知 注解拦截的异常为 BindException

Resolved [org.springframework.validation.BindException: org.springframework.validation.BeanPropertyBindingResult: 1 errors<EOL>Field error in object 'loginRequestParam' on field 'mobile': rejected value [11]; codes [IsMobile.loginRequestParam.mobile,IsMobile.mobile,IsMobile.java.lang.String,IsMobile]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [loginRequestParam.mobile,mobile]; arguments []; default message [mobile],true]; default message [手机号码 格式错误]]

全局异常处理

1、 首先 定义 异常的枚举信息

package com.example.seckill.common;

/**
 * 公共返回对象枚举
 *
 * @author: LC
 * @date 2022/3/2 1:44 下午
 * @ClassName: RespBean
 */

public enum RespBeanEnum {

    //通用
    SUCCESS(200, "SUCCESS"),
    ERROR(500, "服务端异常"),

    //登录模块
    LOGIN_ERROR(500210, "用户名或者密码不正确"),
    MOBILE_ERROR(500211, "手机号码格式不正确"),
    BIND_ERROR(500212, "参数校验异常"),
    MOBILE_NOT_EXIST(500213, "手机号码不存在"),
    PASSWORD_UPDATE_FAIL(500214, "更新密码失败"),
    SESSION_ERROR(500215, "用户SESSION不存在"),


    //秒杀模块
    EMPTY_STOCK(500500, "库存不足"),
    REPEATE_ERROR(500501, "该商品每人限购一件"),
    REQUEST_ILLEGAL(500502, "请求非法，请重新尝试"),
    ERROR_CAPTCHA(500503, "验证码错误，请重新输入"),
    ACCESS_LIMIT_REACHED(500504, "访问过于频繁，请稍后重试"),
    //订单模块5003xx
    ORDER_NOT_EXIST(500300, "订单不存在"),


    ;

    private final Integer code;
    private final String message;

    public Integer getCode() {
        return code;
    }

    public String getMessage() {
        return message;
    }

    RespBeanEnum(Integer code, String message) {
        this.code = code;
        this.message = message;
    }
}

2、 定义 返回信息的格式

package com.example.seckill.common;

/**
 * 公共返回对象
 *
 * @author: LC
 * @date 2022/3/2 1:50 下午
 * @ClassName: RespBean
 */
public class RespBean {

    private long code;
    private String message;
    private Object object;

    public static RespBean success() {
        return new RespBean(RespBeanEnum.SUCCESS.getCode(), RespBeanEnum.SUCCESS.getMessage(), null);
    }

    public static RespBean success(Object object) {
        return new RespBean(RespBeanEnum.SUCCESS.getCode(), RespBeanEnum.SUCCESS.getMessage(), object);
    }

    public static RespBean error(RespBeanEnum respBeanEnum) {
        return new RespBean(respBeanEnum.getCode(), respBeanEnum.getMessage(), null);
    }

    public static RespBean error(RespBeanEnum respBeanEnum, Object object) {
        return new RespBean(respBeanEnum.getCode(), respBeanEnum.getMessage(), object);
    }

    public RespBean(long code, String message, Object object) {
        this.code = code;
        this.message = message;
        this.object = object;
    }

    public RespBean() {

    }

    public long getCode() {
        return code;
    }

    public void setCode(long code) {
        this.code = code;
    }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    public Object getObject() {
        return object;
    }

    public void setObject(Object object) {
        this.object = object;
    }
}

3、 定义 全局异常处理类

package com.example.seckill.exception;

import com.example.seckill.common.RespBeanEnum;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

/**
 *
 * 全局异常
 */
@Data
@AllArgsConstructor
@NoArgsConstructor
public class GlobalException extends RuntimeException{

    RespBeanEnum respBeanEnum;

}

4、 定义 异常拦截器

package com.example.seckill.exception;

import com.example.seckill.common.RespBean;
import com.example.seckill.common.RespBeanEnum;
import org.springframework.validation.BindException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;


/**
 * 全局异常拦截器
 *
 */

@RestControllerAdvice
public class GlobalExceptionHandle {


    // 异常拦截
    @ExceptionHandler(Exception.class)
    public RespBean ExceptionHandler(Exception e){

        if (e instanceof GlobalException){
            // 如果拦截的异常是我们定义的异常 则直接return
            GlobalException ex = (GlobalException) e;
            return RespBean.error(ex.getRespBeanEnum());

        }else if (e instanceof BindException){ // 如果是注解拦截的异常 绑定异常
            BindException e1 = (BindException) e;
            RespBean respBean = RespBean.error(RespBeanEnum.BIND_ERROR);
            respBean.setMessage("参数检验异常" + e1.getBindingResult().getAllErrors().get(0).getDefaultMessage()); //显示 具体错误信息
            return respBean;

        }
        return RespBean.error(RespBeanEnum.ERROR);
    }

}

此时就会对 代码中的异常进行拦截 返回到前端，进行展示~