spring boot 使用 jwt

本文旨在介绍如何在spring boot中使用jwt，不会介绍什么是jwt。

一、导入依赖

1. spring-boot依赖

<!--父依赖-->
<parent>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-parent</artifactId>
	<version>2.2.6.RELEASE</version>
	<relativePath/> 
</parent>


<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>org.junit.vintage</groupId>
                <artifactId>junit-vintage-engine</artifactId>
            </exclusion>
            <exclusion>
                <groupId>org.junit.jupiter</groupId>
                <artifactId>junit-jupiter-api</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

2. jwt 依赖

<dependency>
    <groupId>com.auth0</groupId>
    <artifactId>java-jwt</artifactId>
    <version>3.4.0</version>
</dependency>

二、应用

创建一个JwtUtil文件

package cn.edu.swpu.news.util;

import cn.edu.swpu.news.entity.User;
import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTVerificationException;
import com.auth0.jwt.interfaces.DecodedJWT;
import lombok.extern.slf4j.Slf4j;

import java.time.*;
import java.util.HashMap;
import java.util.Map;

/**
 * jwt工具类
 * @author ycwiacb 2020/5/2
 */
@Slf4j
public class JwtUtil {

    //这里填写你自己自定义的SECRET
    private static final String SECRET = "ycwiacb-secret";

    /**生成token*/
    public static String sign(User user) {
        Algorithm algorithm = Algorithm.HMAC256(SECRET);
        Map<String, Object> map = new HashMap<>(16);
        map.put("alg", "HS256");
        map.put("typ", "JWT");
        return JWT.create().withHeader(map)
                .withClaim("userId", user.getId())
                .withClaim("username", user.getUsername())
                .withIssuer("ycwiacb")
                .withIssuedAt(DateUtil.localDateTimeToDate(LocalDateTime.now()))
                .withExpiresAt(DateUtil.localDateTimeToDate(LocalDateTime.now().plusMinutes(30)))
                .sign(algorithm);
    }

    /**验证token并返回id*/
    public static Long verify(String token) {
        long userId = 0L;
        try {
            Algorithm algorithm = Algorithm.HMAC256(SECRET);
            JWTVerifier jwtVerifier = JWT.require(algorithm)
                    .withIssuer("ycwiacb")
                    .build();
            DecodedJWT decodedjwt = jwtVerifier.verify(token);
            userId = decodedjwt.getClaim("userId").asLong();
        } catch (JWTVerificationException e) {
            log.error("解析token失败, exception = {}", e.toString());
        }
        return userId;
    }
}

注意：这里使用的是decodedjwt.getClaim("userId").asLong(); 这里是asLong()，对应的有asString(),而非toString()。

附上DateUtil文件

package cn.edu.swpu.news.util;

import java.time.LocalDateTime;
import java.time.ZoneId;
import java.util.Date;

/**
 * @author ycwiacb 2020/5/5
 */
public class DateUtil {

    /**
     *将LocalDateTime 时间类转化为Date
     * @return Date
     */
    public static Date localDateTimeToDate(LocalDateTime dateTime) {
        return Date.from(dateTime.atZone(ZoneId.of("Asia/Shanghai")).toInstant());
    }
}

测试，JwtUtilTest.java

package cn.edu.swpu.news.util;

import cn.edu.swpu.news.entity.User;
import org.junit.Test;

/**
 * @author ycwiacb 2020/5/10
 */
public class JwtUtilTest {

    @Test
    public void sign() {
        User user = new User();
        user.setId(1L);
        user.setUsername("testUserName");
        System.out.println("测试jwt：token = " + JwtUtil.sign(user));
    }

    @Test
    public void verify() {
        String token = "你生成的token";
        System.out.println("解析token:userId=" + JwtUtil.verify(token));
    }
}

测试结果：

以上就是对jwt的基本操作，具体请看文档

三、参考文档

java-jwt : https://github.com/auth0/java-jwt