Have you learned the necessary global exception handler for the project

Preface

Must be in the usual time to write the project , There must have been abnormal situations , Such as null pointer 、 Data transboundary 、 Type conversion . Every time we have to deal with this exception by ourselves , But there may be many places to deal with in a project , We can't deal with it every time , It's a lot of trouble , At this time, I must think of extracting the exception handling . Unified treatment , So our global exception handling appears .
Two things are important —— The idea of exception handling 、 The global exception is Put exception handling into a class for unified processing .

dried food

As mentioned above, the global exception is a class used to handle exceptions uniformly , So we only need a global exception handling class

package com.xinian.springclud_demo.exception;

import com.xinian.springclud_demo.common.Result;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;

import java.sql.ResultSet;

@RestControllerAdvice
public class GlobalExceptionHandler {
    
    private static final Logger log = LoggerFactory.getLogger(GlobalExceptionHandler.class);


    @ExceptionHandler(value = BusinessException.class)
    public Result zdyExceptionHandeler (BusinessException e){
    
        System.out.println(" Global exception 1");
        log.error(e.getErrorMeg(),e);
        return Result.builder().data(e).build();
    }

    @ExceptionHandler(Exception.class)
    public Result exceptionHandler(Exception e){
    
        System.out.println(" Global exception 2");
        log.error(e.getMessage(),e);
        return Result.builder().data(e).build();
    }


}

Be careful

• @RestControllerAdvice Yes controller enhanced , Able to intercept all SpringMVC The abnormal situation produced
• ExceptionHandler The following parameters specify which method the exception enters for processing

The following is the code for writing exceptions , Not the content of the global exception code

package com.xinian.springclud_demo.controller;

import com.xinian.springclud_demo.common.Result;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/test")
public class TestException {
    
    @GetMapping("/a")
    public Result query(){
    
        int i=1/0;
        Result result = new Result(true," good ",200,"hh");
        return result;
    }

}

Running results

This is the interception ！
This is the end of the global exception interceptor , The following is based on this thing . How to integrate into the project . Construct the basic framework of a project .

1. All items must be return values , First, construct the return value type of an item ！

package com.xinian.springclud_demo.common;

import com.xinian.springclud_demo.enums.StatusEnum;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
public class Result {
    
    /** *  The success of  */
    private Boolean success;
    /** *  Return message  */
    private String message;
    /** *  Return code  */
    private Integer code;
    /** *  Return the data  */
    private Object data;

    /** *  success  * * @return */
    public static Result success() {
    
        return success(null);
    }

    /** *  success  * @param data * @return */
    public static Result success(Object data) {
    
        Result rb = new Result();
        rb.setCode(StatusEnum.SUCCESS.getErrorCode());
        rb.setMessage(StatusEnum.SUCCESS.getErrorMsg());
        rb.setData(data);
        return rb;
    }


    /** *  Failure  */
    public static Result error() {
    
        Result rb = new Result();
        rb.setCode(StatusEnum.FAIL.getErrorCode());
        rb.setMessage(StatusEnum.FAIL.getErrorMsg());
        rb.setData(null);
        return rb;
    }

    /** *  Failure  */
    public static Result error( String message) {
    
        Result rb = new Result();
        rb.setCode(-1);
        rb.setMessage(message);
        rb.setData(null);
        return rb;
    }

}

The return value type is well defined , But there are many situations for the status we return , So we finally define an enumeration to list all the States , I use two here

package com.xinian.springclud_demo.enums;

import lombok.Data;


public enum StatusEnum {
    

    SUCCESS (200," success "),
    NO_PERMISSION(403, " You don't have access to "),
    NO_Auth(401, " unauthorized , Please login for verification "),
    NO_FOUND(404, " No resources found "),
    INTERNAL_SERVER_ERROR(500, " Server exception ,  Please contact the Administrator !"),
    FAIL(502," Failure ");

    private Integer errorCode;
    private String errorMsg;

    StatusEnum(Integer errorCode,String errorMsg){
    
        this.errorCode = errorCode;
        this.errorMsg = errorMsg;
    }
    public Integer getErrorCode() {
    
        return errorCode;
    }

    public String getErrorMsg() {
    
        return errorMsg;
    }

}

If the official abnormal conditions cannot meet your requirements You can also customize exceptions .
You only need to inherit one RuntimeException That's all right. .

package com.xinian.springclud_demo.exception;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class BusinessException  extends RuntimeException{
    
    /** *  Error code  */
    protected  Integer errorCode;
    /** *  Error message  */
    protected String errorMeg;
}

Running results

This is called global exception handling . Isn't it easy , Just need a class , That's what's called extract

Detailed code please check springboot Global exception handling