How to use annotations such as @notnull to verify and handle global exceptions

@NotNul Wait for the use of annotations

Code ： Code cloud
1、 Add dependency

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

2、 stay controller Before requesting parameters + @Vaild

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

3、 On the parameter entity class annotations

@Data
public class LoginRequestParam {
    

    @NotBlank(message = "mobile Can't be empty ")
    @IsMobile
    private String mobile;

    @NotBlank(message = "password Can't be empty ")
    @Length(min = 32,message = "password  The length is not right ")
    private String password;

}

---

here The exception of will not be displayed on the page But will newspaper 400 error , And in Error in background printing , This requires intercepting exceptions

Background error protection information , You know The exception intercepted by the annotation is 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 [ Phone number   Format error ]]

Global exception handling

1、 First Definition Abnormal enumeration information

package com.example.seckill.common;

/** *  Public return object enumeration  * * @author: LC * @date 2022/3/2 1:44  Afternoon  * @ClassName: RespBean */

public enum RespBeanEnum {
    

    // Universal 
    SUCCESS(200, "SUCCESS"),
    ERROR(500, " Server exception "),

    // Login module 
    LOGIN_ERROR(500210, " Incorrect username or password "),
    MOBILE_ERROR(500211, " Incorrect format of mobile phone number "),
    BIND_ERROR(500212, " Parameter verification exception "),
    MOBILE_NOT_EXIST(500213, " Mobile number does not exist "),
    PASSWORD_UPDATE_FAIL(500214, " Failed to update password "),
    SESSION_ERROR(500215, " user SESSION non-existent "),


    // Second kill module 
    EMPTY_STOCK(500500, " Insufficient inventory "),
    REPEATE_ERROR(500501, " This product is limited to one per person "),
    REQUEST_ILLEGAL(500502, " Illegal request , Please try again "),
    ERROR_CAPTCHA(500503, " Verification code error , Please re-enter "),
    ACCESS_LIMIT_REACHED(500504, " Too many visits , Please try again later "),
    // Order module 5003xx
    ORDER_NOT_EXIST(500300, " The order does not exist "),


    ;

    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、 Definition The format of the returned information

package com.example.seckill.common;

/** *  Public return object  * * @author: LC * @date 2022/3/2 1:50  Afternoon  * @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、 Definition Global exception handling class

package com.example.seckill.exception;

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

/** * *  Global exception  */
@Data
@AllArgsConstructor
@NoArgsConstructor
public class GlobalException extends RuntimeException{
    

    RespBeanEnum respBeanEnum;

}

4、 Definition Exception interceptor

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;


/** *  Global exception interceptor  * */

@RestControllerAdvice
public class GlobalExceptionHandle {
    


    //  Abnormal interception 
    @ExceptionHandler(Exception.class)
    public RespBean ExceptionHandler(Exception e){
    

        if (e instanceof GlobalException){
    
            //  If the intercepted exception is our defined exception   directly return
            GlobalException ex = (GlobalException) e;
            return RespBean.error(ex.getRespBeanEnum());

        }else if (e instanceof BindException){
     //  If it is an exception intercepted by annotations   Binding exception 
            BindException e1 = (BindException) e;
            RespBean respBean = RespBean.error(RespBeanEnum.BIND_ERROR);
            respBean.setMessage(" Abnormal parameter inspection " + e1.getBindingResult().getAllErrors().get(0).getDefaultMessage()); // Show   Specific error messages 
            return respBean;

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

}

At this point it will be right Intercept exceptions in the code Back to front end , To display ~