SpringBoot | 使用jwt令牌实现登录认证，使用Md5加密实现注册

对于登录认证中的令牌，其实就是一段字符串，那为什么要那么麻烦去用jwt令牌？其实对于登录这个业务，在平常我们实现这个功能时，可能大部分都是通过比对用户名和密码，只要正确，就登录成功；而并不会考虑到使用jwt令牌。

但是其实使用jwt令牌的好处是：

它可以承载业务数据，减少后续请求查询数据库的次数；
并且可以防篡改，保证信息的合法性和有效性。

前提：

pom.xml文件添加以下依赖：

<!--      java-jwt坐标--><dependency><groupId>com.auth0</groupId><artifactId>java-jwt</artifactId><version>4.4.0</version></dependency><!--      单元测试的坐标--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId></dependency><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>3.8.1</version><scope>compile</scope></dependency>

测试代码：

package com.xu;import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.interfaces.Claim;
import com.auth0.jwt.interfaces.DecodedJWT;
import org.junit.jupiter.api.Test;import java.util.Date;
import java.util.HashMap;
import java.util.Map;public class JwtTest {@Testpublic void testGen(){Map<String,Object> claims=new HashMap<>();claims.put("id",1);claims.put("username","张三");//生成jwt的代码String token= JWT.create().withClaim("user",claims)//添加载荷.withExpiresAt(new Date(System.currentTimeMillis()+1000*60*60*3)).sign(Algorithm.HMAC256("xu"));//指定算法，配置密钥System.out.println(token);}@Testpublic void testParse(){//定义字符串，模拟用户传递过来的tokenString token="eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyIjp7ImlkIjoxLCJ1c2VybmFtZSI6IuW8oOS4iSJ9LCJleHAiOjE3MTk0ODgxMjR9.RtU7DxCKObLO2MyVlh0g7GbwxCBI2H23y9kn0kt34Lc";JWTVerifier jwtVerifier=JWT.require(Algorithm.HMAC256("xu")).build();DecodedJWT decodedJWT= jwtVerifier.verify(token);//验证token，生成一个解析后的jwt对象Map<String, Claim> claims=decodedJWT.getClaims();System.out.println(claims.get("user"));}}

jwt令牌的生成：

验证jwt令牌：

使用jwt令牌实现登录功能，并且进入需要登录为前提的页面进行判断

项目框架目录：

pojo层：

package com.xu.pojo;
import lombok.Data;import java.time.LocalDateTime;
//lombok  在编译阶段,为实体类自动生成setter  getter toString
// pom文件中引入依赖   在实体类上添加注解
@Data
public class User {private Integer id;//主键IDprivate String username;//用户名private String password;//密码private String nickname;//昵称private String email;//邮箱private String userPic;//用户头像地址private LocalDateTime createTime;//创建时间private LocalDateTime updateTime;//更新时间
}

package com.xu.pojo;import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;//统一响应结果@NoArgsConstructor
@AllArgsConstructor
@Data
public class Result<T> {private Integer code;//业务状态码  0-成功  1-失败private String message;//提示信息private T data;//响应数据//快速返回操作成功响应结果(带响应数据)public static <E> Result<E> success(E data) {return new Result<>(0, "操作成功", data);}//快速返回操作成功响应结果public static Result success() {return new Result(0, "操作成功", null);}public static Result error(String message) {return new Result(1, message, null);}
}

service层：

package com.xu.service;import com.xu.pojo.User;
import org.springframework.stereotype.Service;@Service
public interface UserService {//根据用户名查询用户User findByUserName(String username);//注册void register(String username, String password);
}

package com.xu.service.impl;import com.xu.mapper.UserMapper;
import com.xu.pojo.User;
import com.xu.service.UserService;
import com.xu.utils.Md5Util;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;@Service
public class UserServiceImpl implements UserService {@Autowiredprivate UserMapper userMapper;@Overridepublic User findByUserName(String username) {User u=userMapper.findByUserName(username);return u;}@Overridepublic void register(String username, String password) {//加密String md5String= Md5Util.getMD5String(password);//添加userMapper.add(username,md5String);}
}

mapper层：

package com.xu.mapper;import com.xu.pojo.User;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
@Mapper
public interface UserMapper {//根据用户名查询用户@Select("select * from user where username=#{username}")User findByUserName(String username);//添加@Insert("insert into user(username,password,create_time,update_time)"+" values(#{username},#{password},now(),now())")void add(String username, String password);
}

utils层：

实现登录的密码加密功能：

package com.xu.utils;import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;public class Md5Util {/*** 默认的密码字符串组合，用来将字节转换成 16 进制表示的字符,apache校验下载的文件的正确性用的就是默认的这个组合*/protected static char hexDigits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};protected static MessageDigest messagedigest = null;static {try {messagedigest = MessageDigest.getInstance("MD5");} catch (NoSuchAlgorithmException nsaex) {System.err.println(Md5Util.class.getName() + "初始化失败，MessageDigest不支持MD5Util。");nsaex.printStackTrace();}}/*** 生成字符串的md5校验值** @param s* @return*/public static String getMD5String(String s) {return getMD5String(s.getBytes());}/*** 判断字符串的md5校验码是否与一个已知的md5码相匹配** @param password  要校验的字符串* @param md5PwdStr 已知的md5校验码* @return*/public static boolean checkPassword(String password, String md5PwdStr) {String s = getMD5String(password);return s.equals(md5PwdStr);}public static String getMD5String(byte[] bytes) {messagedigest.update(bytes);return bufferToHex(messagedigest.digest());}private static String bufferToHex(byte bytes[]) {return bufferToHex(bytes, 0, bytes.length);}private static String bufferToHex(byte bytes[], int m, int n) {StringBuffer stringbuffer = new StringBuffer(2 * n);int k = m + n;for (int l = m; l < k; l++) {appendHexPair(bytes[l], stringbuffer);}return stringbuffer.toString();}private static void appendHexPair(byte bt, StringBuffer stringbuffer) {char c0 = hexDigits[(bt & 0xf0) >> 4];// 取字节中高 4 位的数字转换, >>>// 为逻辑右移，将符号位一起右移,此处未发现两种符号有何不同char c1 = hexDigits[bt & 0xf];// 取字节中低 4 位的数字转换stringbuffer.append(c0);stringbuffer.append(c1);}}

实现注册的jwt令牌功能：

package com.xu.utils;import com.auth0.jwt.JWT;
import com.auth0.jwt.algorithms.Algorithm;import java.util.Date;
import java.util.Map;public class JwtUtil {private static final String KEY = "xu";//接收业务数据,生成token并返回public static String genToken(Map<String, Object> claims) {return JWT.create().withClaim("claims", claims).withExpiresAt(new Date(System.currentTimeMillis() + 1000 * 60 * 60 * 12)).sign(Algorithm.HMAC256(KEY));}//接收token,验证token,并返回业务数据public static Map<String, Object> parseToken(String token) {return JWT.require(Algorithm.HMAC256(KEY)).build().verify(token).getClaim("claims").asMap();}}

controller层：

package com.xu.controller;import com.xu.pojo.Result;
import com.xu.pojo.User;
import com.xu.service.UserService;
import com.xu.utils.JwtUtil;
import com.xu.utils.Md5Util;
import jakarta.validation.constraints.Pattern;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import java.util.HashMap;
import java.util.Map;@RestController
@RequestMapping("/user")
@Validated
public class UserController {@Autowiredprivate UserService userService;@PostMapping("register")public Result register(@Pattern(regexp = "^\\S{5,16}$")String username, @Pattern(regexp = "^\\S{5,16}$")String password){//查询用户User u=userService.findByUserName(username);if(u==null){//没有占用，注册userService.register(username,password);return Result.success();}else {//占用return Result.error("用户名已被占用");}}@PostMapping("login")public Result<String> login(@Pattern(regexp = "^\\S{5,16}$")String username, @Pattern(regexp = "^\\S{5,16}$")String password){//根据用户名查询用户User loginUser=userService.findByUserName(username);//判断用户是否存在if(loginUser==null){return Result.error("用户名错误");}//判断密码是否正确if(Md5Util.getMD5String(password).equals(loginUser.getPassword())){//登录成功Map<String,Object> claims=new HashMap<>();claims.put("id",loginUser.getId());claims.put("username",loginUser.getUsername());String token= JwtUtil.genToken(claims);return Result.success(token);}return Result.error("密码错误");}
}

使用localhost:8080/article/list测试登录中jwt令牌的功能：

package com.xu.controller;import com.xu.pojo.Result;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;@RestController
@RequestMapping("/article")
public class ArticleController {@GetMapping("/list")public Result<String> list(){return Result.success("所有文章数据");}
}

interceptors层（令牌验证）：

package com.xu.interceptors;import com.xu.pojo.Result;
import com.xu.utils.JwtUtil;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;import java.util.Map;@Component
public class LoginInterceptor implements HandlerInterceptor {@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {//令牌验证String token=request.getHeader("Authorization");//验证tokentry {Map<String,Object> claims= JwtUtil.parseToken(token);//放行return true;}catch (Exception e){response.setStatus(401);//不放行return false;}}
}

exception层：

package com.xu.exception;import com.xu.pojo.Result;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;@RestControllerAdvice
public class GlobalExceptionHandler {@ExceptionHandler(Exception.class)public Result handleException(Exception e){e.printStackTrace();return Result.error(StringUtils.hasLength(e.getMessage())?e.getMessage():"操作失败");}
}

config层（没有header的“令牌”，不拦截登录，注册页面）：

package com.xu.config;import com.xu.interceptors.LoginInterceptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
@Configuration
public class WebConfig implements WebMvcConfigurer {@Autowiredprivate LoginInterceptor loginInterceptor;@Overridepublic void addInterceptors(InterceptorRegistry registry) {//登录接口和注册接口不拦截registry.addInterceptor(loginInterceptor).excludePathPatterns("/user/login","/user/register");}
}

pom.xml文件：

<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><parent><artifactId>spring-boot-starter-parent</artifactId><groupId>org.springframework.boot</groupId><version>3.1.3</version></parent><groupId>com.xu</groupId><artifactId>big-news</artifactId><version>1.0-SNAPSHOT</version><packaging>jar</packaging><name>big-news</name><url>http://maven.apache.org</url><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding></properties><dependencies>
<!--    web依赖--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId>
<!--      <version>3.3.0</version>--></dependency><!--    mybatis依赖--><dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>3.0.0</version></dependency>
<!--    mysql驱动依赖--><dependency><groupId>com.mysql</groupId><artifactId>mysql-connector-j</artifactId>
<!--      <version></version>--></dependency><!--      lombok依赖--><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId></dependency><!--      validation依赖--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-validation</artifactId></dependency><!--      java-jwt坐标--><dependency><groupId>com.auth0</groupId><artifactId>java-jwt</artifactId><version>4.4.0</version></dependency><!--      单元测试的坐标--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId></dependency><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>3.8.1</version><scope>compile</scope></dependency></dependencies>
</project>

分析：

用户登录：

用户登录成功后，系统会自动下发JWT令牌，然后在后续的每次请求中，浏览器都需要在请求头header中携带到服务端，请求头的名称为 Authorization，值为true 登录时下发的JWT令牌。

用户注册：

用户注册使用Md5加密，防止数据库的密码被泄露，并且在用户注册时使用validation校验参数。