JWT练习—jwtdemo

一、导入依赖

在pom文件中加入如下依赖

        
            io.jsonwebtoken
            jjwt
            0.9.1
        

        
            org.springframework.boot
            spring-boot-configuration-processor
            true
        

二、修改配置文件

在application.properties中添加如下内容

################################# 自定义属性 #################################
#jwt配置
#密钥
jwt.secret=com.jiekki
#过期时间(30分钟)
jwt.expiration=1800000

三、实体类编写

这里随便弄了个Student类，实际开发中需要用UserDetails类

package com.example.jwtdemo;

public class Student {
    private String stuId;
    private String stuName;
    private int age;

    public Student() {
    }

    public Student(String stuId, String stuName, int age) {
        this.stuId = stuId;
        this.stuName = stuName;
        this.age = age;
    }

    public String getStuId() {
        return stuId;
    }

    public void setStuId(String stuId) {
        this.stuId = stuId;
    }

    public String getStuName() {
        return stuName;
    }

    public void setStuName(String stuName) {
        this.stuName = stuName;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

四、编写JwtUtils工具类

package com.example.jwtdemo;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

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

/**
 * jwt工具类
 */
@Component
@ConfigurationProperties("jwt")//此注解会将application.properties中的jwt.的属性配置对应到JwtUtils类中的成员变量
public class JwtUtils {
    //密钥
    private String secret;
    // 过期时间 毫秒
    private Long expiration;
/**
 * 从数据声明生成令牌
 * @param claims 数据声明
 * @return 令牌
*/
    private String generateToken(Map<String, Object> claims) {
        Date expirationDate = new Date(System.currentTimeMillis() + expiration);
        return
                Jwts.builder().setClaims(claims).setExpiration(expirationDate).signWith(SignatureAlgorithm.HS512, secret).compact();
    }
    /**
     * 从令牌中获取数据声明
     * @param token 令牌
     * @return 数据声明
     */
    public Claims getClaimsFromToken(String token) {
        Claims claims;
        try {
            claims =
                    Jwts.parser().setSigningKey(secret).parseClaimsJws(token).getBody();
        } catch (Exception e) {
            claims = null;
        }
        return claims;
    }
    /**
     * 生成令牌
     *
     * @param student 学生对象
     * @return 令牌
     */
    public String generateToken(Student student) {
        Map<String, Object> claims = new HashMap<>(2);
        claims.put(Claims.SUBJECT, student.getStuName());
        claims.put("age", student.getAge());
        return generateToken(claims);
    }
    /**
     * 从令牌中获取用户名
     *
     * @param token 令牌
     * @return 用户名
     */
    public String getUsernameFromToken(String token) {
        String stuName;
        try {
            Claims claims = getClaimsFromToken(token);
            stuName = claims.getSubject();
        } catch (Exception e) {
            stuName = null;
        }
        return stuName;
    }
    /**
     * 判断令牌是否过期
     *
     * @param token 令牌
     * @return 是否过期
     */
    public Boolean isTokenExpired(String token) {
        Claims claims = getClaimsFromToken(token);
        Date expiration = claims.getExpiration();
        return expiration.before(new Date());
    }
    /**
     * 刷新令牌
     * @param token 原令牌
     * @return 新令牌
     */
    public String refreshToken(String token) {
        String refreshedToken;
        try {
            Claims claims = getClaimsFromToken(token);
            claims.put(Claims.ISSUED_AT, new Date());
            refreshedToken = generateToken(claims);
        } catch (Exception e) {
            refreshedToken = null;
        }
        return refreshedToken;
    }
    /**
     * 验证令牌
     *
     * @param token 令牌
     * @param  student 学生对象
     * @return 是否有效
     */
    public Boolean validateToken(String token, Student student) {
        //从token中取出学生名
        String username = getUsernameFromToken(token);
        //如果从token中取出的学生名与传入的学生对象的名称一致，并且token令牌没有过期，那么就返回true
        return (username.equals(student.getStuName()) && !isTokenExpired(token));
    }

    public String getSecret() {
        return secret;
    }

    public void setSecret(String secret) {
        this.secret = secret;
    }

    public Long getExpiration() {
        return expiration;
    }

    public void setExpiration(Long expiration) {
        this.expiration = expiration;
    }
}

五、测试

package com.example.jwtdemo;

import io.jsonwebtoken.Claims;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
class JwtdemoApplicationTests {
    @Autowired
    JwtUtils jwtUtils;

    @Test
    void 测试生成token() {
        Student student=new Student("1723111028","jiekki",13);
        String token = jwtUtils.generateToken(student);
        System.out.println(token);
    }
    @Test
    void 测试获取用户名(){
        String token="eyJhbGciOiJIUzUxMiJ9.eyJleHAiOjE2ODEzMDk0NTEsInN1YiI6ImppZWtraSIsImFnZSI6MTN9.2MVhaxzjczrSfLvoM-QFeX1w5L1NyPYtea3CffIZjxOckhk6nx7cHp5UJae6k5B4kuMqYhnWcQ139RFeRYCI4Q";
        String username = jwtUtils.getUsernameFromToken(token);
        System.out.println(username);
    }

    @Test
    void 从令牌中获取数据声明(){
        String token="eyJhbGciOiJIUzUxMiJ9.eyJleHAiOjE2ODEzMDk0NTEsInN1YiI6ImppZWtraSIsImFnZSI6MTN9.2MVhaxzjczrSfLvoM-QFeX1w5L1NyPYtea3CffIZjxOckhk6nx7cHp5UJae6k5B4kuMqYhnWcQ139RFeRYCI4Q";
        Claims claims = jwtUtils.getClaimsFromToken(token);
        String stuName = claims.get("sub",String.class);
        int age = claims.get("age",Integer.class);
        System.out.println(stuName);
        System.out.println(age);
        System.out.println(claims);
    }

}