Spring全局异常处理HandlerExceptionResolver使用

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>

java_78">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);}}

java_135">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 {@Autowiredprivate UserMapperMaster userMapperMaster;@RequestMapping(value = "/login")@ResponseBodypublic 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();}
}

java_178">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;}
}

java_225">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());@Overridepublic 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();}
}