前言

在 Controller 里提供接口，通常需要捕捉異常，進(jìn)行異常處理。最簡單的方法使用try/catch進(jìn)行異常捕捉。

當(dāng)方法很多，每個都需要 try catch，代碼會顯得臃腫，寫起來也比較麻煩。
這時就需要進(jìn)行統(tǒng)一的異常處理。

1.使用方法

通過 Spring 的 AOP 特性就可以很方便的實現(xiàn)異常的統(tǒng)一處理：使用@ControllerAdvice、@RestControllerAdvice捕獲運行時異常。

代碼結(jié)構(gòu)

image.png

新建異常枚舉類

package com.local.dev.root.devroot.common.enums;

/**
 * 異常枚舉類
 */
public enum ExceptionEnum {
    // 400
    BAD_REQUEST("400", "請求數(shù)據(jù)格式不正確!"),
    UNAUTHORIZED("401", "登錄憑證過期!"),
    FORBIDDEN("403", "沒有訪問權(quán)限!"),
    NOT_FOUND("404", "請求的資源找不到!"),
    // 500
    INTERNAL_SERVER_ERROR("500", "服務(wù)器內(nèi)部錯誤!"),
    SERVICE_UNAVAILABLE("503", "服務(wù)器正忙，請稍后再試!"),
    // 未知異常
    UNKNOWN("10000", "未知異常!"),
    // 自定義
    IS_NOT_NULL("10001","%s不能為空");

    /**
     * 錯誤碼
     */
    private String code;

    /**
     * 錯誤描述
     */
    private String msg;

    ExceptionEnum(String code, String msg) {
        this.code = code;
        this.msg = msg;
    }

    public String getCode() {
        return code;
    }

    public String getMsg() {
        return msg;
    }
}

自定義異常類

package com.local.dev.root.devroot.common.exception;

import com.local.dev.root.devroot.common.enums.ExceptionEnum;

/**
 * 自定義業(yè)務(wù)異常類
 */
public class BusinessException extends RuntimeException {

    private ExceptionEnum exceptionEnum;
    private String code;
    private String errorMsg;

    public BusinessException() {
        super();
    }

    public BusinessException(ExceptionEnum exceptionEnum) {
        super("{code:" + exceptionEnum.getCode() + ",errorMsg:" + exceptionEnum.getMsg() + "}");
        this.exceptionEnum = exceptionEnum;
        this.code = exceptionEnum.getCode();
        this.errorMsg = exceptionEnum.getMsg();
    }

    public BusinessException(String code, String errorMsg) {
        super("{code:" + code + ",errorMsg:" + errorMsg + "}");
        this.code = code;
        this.errorMsg = errorMsg;
    }

    public BusinessException(String code, String errorMsg, Object... args) {
        super("{code:" + code + ",errorMsg:" + String.format(errorMsg, args) + "}");
        this.code = code;
        this.errorMsg = String.format(errorMsg, args);
    }

    public ExceptionEnum getExceptionEnum() {
        return exceptionEnum;
    }

    public String getErrorMsg() {
        return errorMsg;
    }

    public void setErrorMsg(String errorMsg) {
        this.errorMsg = errorMsg;
    }

    public String getCode() {
        return code;
    }

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

ExceptionHandlerConfig.java
@RestControllerAdvice，統(tǒng)一異常處理

package com.local.dev.root.devroot.common.config.exception;

import com.local.dev.root.devroot.common.enums.ExceptionEnum;
import com.local.dev.root.devroot.common.exception.BusinessException;
import com.local.dev.root.devroot.common.exception.ErrorPageException;
import com.local.dev.root.devroot.common.pojo.ApiResponse;
import com.local.dev.root.devroot.common.util.ErrorUtil;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.ResponseStatus;
import org.springframework.web.bind.annotation.RestControllerAdvice;

/**
 * RestControllerAdvice，統(tǒng)一異常處理
 */
@Slf4j
@RestControllerAdvice
public class ExceptionHandlerConfig {

    /**
     * 業(yè)務(wù)異常處理
     *
     * @param e 業(yè)務(wù)異常
     * @return
     */
    @ExceptionHandler(value = BusinessException.class)
    @ResponseBody
    public ApiResponse exceptionHandler(BusinessException e) {
        log.error(ErrorUtil.errorInfoToString(e));
        return ApiResponse.error(e.getCode(), e.getErrorMsg());
    }

    /**
     * 未知異常處理
     */
    @ExceptionHandler(value = Exception.class)
    @ResponseBody
    public ApiResponse exceptionHandler(Exception e) {
        // 把錯誤信息輸入到日志中
        log.error(ErrorUtil.errorInfoToString(e));
        return ApiResponse.error(ExceptionEnum.UNKNOWN.getCode(),
                ExceptionEnum.UNKNOWN.getMsg());
    }

    /**
     * 錯誤頁面異常
     */
    @ExceptionHandler(value = ErrorPageException.class)
    @ResponseBody
    public ApiResponse exceptionHandler(ErrorPageException e) {
        log.error(ErrorUtil.errorInfoToString(e));
        return ApiResponse.error(e.getCode(), e.getErrorMsg());
    }

    /**
     * 空指針異常
     */
    @ExceptionHandler(value = NullPointerException.class)
    @ResponseBody
    public ApiResponse exceptionHandler(NullPointerException e) {
        log.error(ErrorUtil.errorInfoToString(e));
        return ApiResponse.error(ExceptionEnum.INTERNAL_SERVER_ERROR.getCode(),
                ExceptionEnum.INTERNAL_SERVER_ERROR.getMsg());
    }
}

測試類

package com.local.dev.root.devroot.controller;

import com.local.dev.root.devroot.common.pojo.ApiResponse;
import com.local.dev.root.devroot.service.dev.TestServiceImpl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/hello")
public class HelloWorld {

    @Autowired
    private TestServiceImpl testServiceImpl;
    @RequestMapping("world")
    public String HelloWorld() {
        return "Hello World!";
    }

    @RequestMapping("error1")
    public ApiResponse Error1() {
        return ApiResponse.ok();
    }
    @RequestMapping("error2")
    public ApiResponse Error2() {
        String msg = null;
        msg.equals("xx");
        return ApiResponse.ok("訪問成功");
    }
    @RequestMapping("error3")
    public ApiResponse Error3() {
        testServiceImpl.getBusinessException();
        return ApiResponse.ok("訪問成功");
    }
}

testServiceImpl 拋出自定義異常

package com.local.dev.root.devroot.service.dev;

import com.local.dev.root.devroot.common.enums.ExceptionEnum;
import com.local.dev.root.devroot.common.exception.BusinessException;
import org.springframework.stereotype.Service;

@Service
public class TestServiceImpl {

    public Object getBusinessException() {
        throw new BusinessException(ExceptionEnum.IS_NOT_NULL.getCode(),
                ExceptionEnum.IS_NOT_NULL.getMsg(), "參數(shù)");
    }
}

ErrorUtil工具類

package com.local.springboot.springbootcommon.utils;

import java.io.PrintWriter;
import java.io.StringWriter;

/**
 * 捕獲報錯日志處理工具類
 */
public class ErrorUtil {

    /**
     * Exception出錯的棧信息轉(zhuǎn)成字符串
     * 用于打印到日志中
     */
    public static String errorInfoToString(Throwable e) {
        //try-with-resource語法糖 處理機(jī)制
        try(StringWriter sw = new StringWriter(); PrintWriter pw = new PrintWriter(sw)){
            e.printStackTrace(pw);
            pw.flush();
            sw.flush();
            return sw.toString();
        }catch (Exception ignored){
            throw new RuntimeException(ignored.getMessage(),ignored);
        }
    }
}

ApiResponse

package com.local.springboot.springbootcommon.reponse;

import java.util.HashMap;

/**
 * @author: MaoDeShu
 * @date: 2021-09-17 11:29
 * @Description: API請求返回類
 **/
public class ApiResponse extends HashMap<String, Object> {
    public ApiResponse() {
        put("code", 200);
        put("msg", "success");
    }

    public ApiResponse(String code, String msg) {
        super(2);
        put("code", code);
        put("msg", msg);
    }

    public static ApiResponse ok() {
        ApiResponse r = new ApiResponse();
        r.put("msg", "操作成功");
        return r;
    }

    public static ApiResponse msg(String msg) {
        ApiResponse r = new ApiResponse();
        r.put("msg", msg);
        return r;
    }

    public static ApiResponse ok(Object obj) {
        ApiResponse r = new ApiResponse();
        r.put("code", 200);
        r.put("results", obj);
        return r;
    }

    public static ApiResponse error() {
        return error("500", "未知異常，請聯(lián)系管理員");
    }

    public static ApiResponse error(String msg) {
        return error("500", msg);
    }

    public static ApiResponse error(String code, String msg) {
        ApiResponse r = new ApiResponse();
        r.put("code", code);
        r.put("msg", msg);
        return r;
    }

    @Override
    public ApiResponse put(String key, Object value) {
        super.put(key, value);
        return this;
    }

    /**
     * 分頁
     *
     * @param page
     * @return
     */
    public ApiResponse page(Object page) {
        return put("page", page);
    }


    public ApiResponse result(Object obj) {
        super.put("result", obj);
        return this;
    }
}