Spring全局异常处理HandlerExceptionResolver使用

news2024/9/28 15:33:26

1 引言

全局异常处理在项目中经常会用到，主要作用包括统一处理异常、提供友好的错误信息、避免应用程序崩溃、记录异常日志、避免异常信息泄露等等。下文将以实现HandlerExceptionResolver接口的方式，实现全局异常处理功能及常规用法。

2 代码

下面列出几个关键文件进行介绍，源码链接在文章最后。
在这里插入图片描述

2.1 pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.zeroone</groupId>
    <artifactId>zeroone</artifactId>
    <version>1.0</version>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <!--  为Spring Boot项目提供一系列默认的配置和依赖管理-->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.3.2</version>
        <relativePath/>
    </parent>

    <dependencies>
        <!--  Spring Boot核心依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <!-- Spring Boot单元测试和集成测试的依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- Spring Boot构建Web应用程序的依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!-- mysql驱动-->
        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
        </dependency>
        <!-- mybatis-plus核心依赖-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-spring-boot3-starter</artifactId>
            <version>3.5.7</version>
        </dependency>
        <!-- 阿里数据库连接池 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-3-starter</artifactId>
            <version>1.2.23</version>
        </dependency>
        <!-- 阿里JSON解析库-->
        <dependency>
            <groupId>com.alibaba.fastjson2</groupId>
            <artifactId>fastjson2</artifactId>
            <version>2.0.52</version>
        </dependency>


    </dependencies>

</project>

2.2 ReturnObj.java

该类主要用于构建一个统一的返回结构和返回状态码。

package com.zeroone.entity.common;


import java.util.HashMap;
import java.util.Map;

/**
 * 统一返回结构和返回状态码
 */
public class ReturnObj {
    /**
     * 正常
     */
    public static final int SUCCESS_CODE = 200;
    /**
     * 参数异常
     */
    public static final int BAD_REQUEST_CODE = 400;
    /**
     * 未授权
     */
    public static final int UNAUTHORIZED_CODE = 401;
    /**
     * 系统异常
     */
    public static final int ERROR_CODE = 500;


    private static final String SUCCESS_MSG = "操作成功";

    public static Map<String, Object> build(int code, String msg, Object data) {
        Map<String, Object> map = new HashMap<>();
        map.put("code", code);
        map.put("msg", msg);
        map.put("data", data);
        return map;
    }

    public static Map<String, Object> success() {
        return build(SUCCESS_CODE, SUCCESS_MSG, null);
    }

    public static Map<String, Object> success(Object data) {
        return build(SUCCESS_CODE, SUCCESS_MSG, data);
    }

    public static Map<String, Object> success(String msg, Object data) {
        return build(SUCCESS_CODE, msg, data);
    }


}

2.3 UserController.java

主要用于测试

package com.zeroone.controller;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.zeroone.config.exception.MyRuntimeException;
import com.zeroone.entity.User;
import com.zeroone.entity.common.ReturnObj;
import com.zeroone.mapper.master.UserMapperMaster;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;


@Controller
@RequestMapping("/UserController")
public class UserController {

    @Autowired
    private UserMapperMaster userMapperMaster;

    @RequestMapping(value = "/login")
    @ResponseBody
    public Object login(@RequestBody User user) {
        if (null == user.getPhone() ) {
            throw new MyRuntimeException(ReturnObj.BAD_REQUEST_CODE, "手机号不能为空");
        }
        user.getName().toString();
        return ReturnObj.success();
    }
}

2.4 MyRuntimeException.java

自定义异常，主要用code和msg来区分各种异常场景，无需每种异常都建一个类。

package com.zeroone.config.exception;


/**
 * 自定义异常
 */
public class MyRuntimeException extends RuntimeException {

    /**
     * 异常码
     */
    private int code;

    /**
     * 异常消息
     */
    private String msg;

    public MyRuntimeException(int code, String msg) {
        super(msg);
        this.code = code;
        this.msg = msg;

    }

    public int getCode() {
        return code;
    }

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

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }
}

2.5 HandlerExceptionResolverImpl.java

全局异常处理，只需要实现HandlerExceptionResolver 接口，所有抛出的异常都会调用resolveException方法。在此方法中，根据不同的异常类型，做不同的处理，以达到灵活处理异常的目的。

package com.zeroone.config.exception;

import com.alibaba.fastjson2.JSON;
import com.zeroone.entity.common.ReturnObj;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;

import java.io.IOException;
import java.io.PrintWriter;


/**
 * 全局异常处理器
 */
@Component
public class HandlerExceptionResolverImpl implements HandlerExceptionResolver {

    public final Logger log = LoggerFactory.getLogger(getClass());

    @Override
    public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
        response.setStatus(HttpStatus.OK.value()); // 设置状态码
        response.setCharacterEncoding("UTF-8"); // 设置编码
        int code = ReturnObj.ERROR_CODE;
        String msg = "系统异常";
        // if 自定义异常
        // else 其他异常
        if (ex instanceof MyRuntimeException myEx) {
            code = myEx.getCode();
            msg = myEx.getMsg();
        } else {
            msg = ex.getMessage();
        }
        log.error("Exception is ", ex);
        try {
            PrintWriter writer = response.getWriter();
            writer.print(JSON.toJSONString(ReturnObj.build(code, msg, null)));
            writer.flush();
        } catch (IOException e) {
            log.error("Exception is ", e);
        }
        return new ModelAndView();
    }
}