1.JWT是什么?
JWT,英文全称JSON Web Token:JSON网络令牌。为了在网络应用环境间传递声明而制定的一种基于JSON的开放标准(RFC 7519)。这个规范允许我们使用JWT在客户端和服务端之间传递安全可靠的信息。JWT是一个轻便的安全跨平台传输格式,定义了一个紧凑自包含
的方式,用于通信双方之间作为 JSON 对象安全地传递信息。此信息可以通过数字签名进行验证和信任。
紧凑:这个字符串简洁,数据量小,传输速度快,能通过URL参数、HTTP请求提交的数据以及HTTP Header的方式进行传递。
自包含:负载中包含很多信息,比如用户的ID等。别人拿到这个字符串,就能拿到这些关键的业务信息,从而避免再通过数据库查询等方式得到它们。
JWT的结构 JWT由三段信息用.连接构成的字符串。
Header
.Payload
.Signature
例如:
eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJhdWQiOiIxIn0.ihOZFzg3ZGIbBMneRy-4RMqors1P3nuO-wRJnQtTzWQ |
Header
头部
承载两部分信息:token类型和采用的加密算法
{
"typ": "JWT",
"alg": "HS256"
}
token类型:JWT 加密算法:HS256
Payload
负载
存放有效信息的地方
iss: jwt签发者 sub: jwt所面向的用户 aud: 接收jwt的一方 exp: 过期时间戳(jwt的过期时间,这个过期时间必须要大于签发时间) nbf: 定义在什么时间之前,该jwt都是不可用的 iat: jwt的签发时间 jti: jwt的唯一身份标识,主要用来作为一次性token,从而回避重放攻击
Signature
签名
对头部及负载内容进行签证。采用Header中声明的算法,接收三个参数:base64编码的Header、base64编码的Payload和密钥(secret)进行运算。密钥secret是保存在服务端的,服务端会根据这个密钥进行生成token和进行验证。
2.环境搭建
参考代码仓库里面的mysql模块,这里只贴出docker-compose.yml
version: '3'
services:
mysql:
image: registry.cn-hangzhou.aliyuncs.com/zhengqing/mysql:5.7
container_name: mysql_3306
restart: unless-stopped
volumes:
- "./mysql/my.cnf:/etc/mysql/my.cnf"
- "./mysql/init-file.sql:/etc/mysql/init-file.sql"
- "./mysql/data:/var/lib/mysql"
# - "./mysql/conf.d:/etc/mysql/conf.d"
- "./mysql/log/mysql/error.log:/var/log/mysql/error.log"
- "./mysql/docker-entrypoint-initdb.d:/docker-entrypoint-initdb.d" # init sql script directory -- tips: it can be excute when `/var/lib/mysql` is empty
environment: # set environment,equals docker run -e
TZ: Asia/Shanghai
LANG: en_US.UTF-8
MYSQL_ROOT_PASSWORD: root # set root password
MYSQL_DATABASE: demo # init database name
ports: # port mappping
- "3306:3306"
运行
docker-compose -f docker-compose.yml -p mysql5.7 up -d
初始化表
DROP TABLE IF EXISTS `jwt_user`;
CREATE TABLE `jwt_user`(
`id` varchar(32) CHARACTER SET utf8 NOT NULL COMMENT '用户ID',
`username` varchar(100) CHARACTER SET utf8 NULL DEFAULT NULL COMMENT '登录账号',
`password` varchar(255) CHARACTER SET utf8 NULL DEFAULT NULL COMMENT '密码'
)ENGINE = InnoDB CHARACTER SET = utf8 COMMENT = '用户表' ROW_FORMAT = Compact;
INSERT INTO jwt_user VALUES('1','admin','123');
3.代码工程
实验目标:实现JWT的签发和验证
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">
<parent>
<artifactId>springboot-demo</artifactId>
<groupId>com.et</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>jwt</artifactId>
<properties>
<maven.compiler.source>8</maven.compiler.source>
<maven.compiler.target>8</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-autoconfigure</artifactId>
</dependency>
<!--mysql-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.29</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.5.1</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.47</version>
</dependency>
<dependency>
<groupId>io.jsonwebtoken</groupId>
<artifactId>jjwt</artifactId>
<version>0.9.1</version>
</dependency>
<dependency>
<groupId>com.auth0</groupId>
<artifactId>java-jwt</artifactId>
<version>3.4.0</version>
</dependency>
</dependencies>
</project>
application.yaml
spring:
datasource:
driver-class-name: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://localhost:3306/demo?useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT
username: root
password: root
server:
port: 8088
Jwt生成
package com.et.jwt.service;
import com.auth0.jwt.JWT;
import com.auth0.jwt.algorithms.Algorithm;
import com.et.jwt.entity.User;
import org.springframework.stereotype.Service;
import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.util.Date;
@Service("TokenService")
public class TokenService {
long outHours=1;
public String getToken(User user) {
Instant instant = LocalDateTime.now().plusHours(outHours).atZone(ZoneId.systemDefault()).toInstant();
Date expire = Date.from(instant);
String token="";
// save information to token ,such as: user id and Expires time
token= JWT.create()
.withAudience(user.getId())
.withExpiresAt(expire)
.sign(Algorithm.HMAC256(user.getPassword()));
// use HMAC256 to generate token,key is user's password
return token;
}
}
jwt验证
package com.et.jwt.interceptor;
import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.auth0.jwt.exceptions.JWTVerificationException;
import com.et.jwt.annotation.PassToken;
import com.et.jwt.annotation.UserLoginToken;
import com.et.jwt.entity.User;
import com.et.jwt.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.lang.reflect.Method;
import java.util.Date;
public class AuthenticationInterceptor implements HandlerInterceptor {
@Autowired
UserService userService;
@Override
public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object object) throws Exception {
// get token from http header
String token = httpServletRequest.getHeader("token");
if(!(object instanceof HandlerMethod)){
return true;
}
HandlerMethod handlerMethod=(HandlerMethod)object;
Method method=handlerMethod.getMethod();
//check is included @passtoken annotation? jump if have
if (method.isAnnotationPresent(PassToken.class)) {
PassToken passToken = method.getAnnotation(PassToken.class);
if (passToken.required()) {
return true;
}
}
//check is included @UserLoginToken ?
if (method.isAnnotationPresent(UserLoginToken.class)) {
UserLoginToken userLoginToken = method.getAnnotation(UserLoginToken.class);
if (userLoginToken.required()) {
// excute verify
if (token == null) {
throw new RuntimeException("token invalid,please login again");
}
// get user id from token
String userId;
try {
userId = JWT.decode(token).getAudience().get(0);
} catch (JWTDecodeException j) {
throw new RuntimeException("401");
}
User user = userService.findUserById(userId);
if (user == null) {
throw new RuntimeException("user is not exist,please login again");
}
// verify token
JWTVerifier jwtVerifier = JWT.require(Algorithm.HMAC256(user.getPassword())).build();
try {
jwtVerifier.verify(token);
if (JWT.decode(token).getExpiresAt().before(new Date())) {
throw new RuntimeException("token Expires");
}
} catch (JWTVerificationException e) {
throw new RuntimeException("401");
}
return true;
}
}
return true;
}
@Override
public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
}
@Override
public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
}
}
以上只是一些关键代码,所有代码请参见下面代码仓库
代码仓库
https://github.com/Harries/springboot-demo
4.测试
启动Spring Boot应用
登录系统
http://localhost:8088/api/login?username=admin&password=123
{
"user": {
"username": "admin",
"password": "123",
"id": "1"
},
"token": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJhdWQiOiIxIn0.ihOZFzg3ZGIbBMneRy-4RMqors1P3nuO-wRJnQtTzWQ"
}
在header里面设置 token,访问
http://localhost:8088/api/getMessage
5.引用
https://www.v2ex.com/t/817906
http://www.liuhaihua.cn/archives/710374.html
https://github.com/ChuaWi/SpringBoot-JWT/tree/master
6.Questions
这里留2个问题给读者
过期了如何刷新token呢?保证过期时候重新登录,而不是后台自动刷新,一直不过期?
如果要实现强制下线用户功能,该如何实现呢?