【107】Java使用JWT的小例子。使用HMAC256算法加密。

我利用 JWT 官网提供的 Java 模块，写了个加密和解密token的例子。这个例子使用Maven管理项目，源代码共包含三个文件：Encrypt.java、Decrypt、Main.java

pom.xml

<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>4.0.0modelVersion>
    <groupId>zhangchaogroupId>
    <artifactId>testJavaJwtartifactId>
    <version>0.0.1-SNAPSHOTversion>

    <properties>
        <project.build.sourceEncoding>UTF-8project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8project.reporting.outputEncoding>
        <java.version>1.8java.version>
        <maven.compiler.source>1.8maven.compiler.source>
        <maven.compiler.target>1.8maven.compiler.target>
    properties>

    <dependencies>
        <dependency>
            <groupId>com.auth0groupId>
            <artifactId>java-jwtartifactId>
            <version>3.1.0version>
        dependency>
    dependencies>
project>

Encrypt.java

package zhangchao;

import java.io.UnsupportedEncodingException;
import java.util.Date;

import com.auth0.jwt.JWT;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTCreationException;

/**
 * 加密
 * @author 张超
 *
 */
public final class Encrypt {

    /**
     * 生成加密后的token
     * @param isVip 是不是VIP,true表示是VIP，false表示不是VIP。
     * @param username 用户名
     * @param name  姓名
     * @return 加密后的token
     */
    public String getToken(final boolean isVip, final String username,
            final String name) {
        String token = null;
        try {
            Date expiresAt = new Date(System.currentTimeMillis() + 24L * 60L * 3600L * 1000L);
            token = JWT.create()
                .withIssuer("auth0")
                .withClaim("isVip", isVip)
                .withClaim("username", username)
                .withClaim("name", name)
                .withExpiresAt(expiresAt)
                // 使用了HMAC256加密算法。
                // mysecret是用来加密数字签名的密钥。
                .sign(Algorithm.HMAC256("mysecret"));
        } catch (JWTCreationException exception){
            //Invalid Signing configuration / Couldn't convert Claims.
        } catch (IllegalArgumentException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return token;
    }
}

Decrypt.java

package zhangchao;

import java.io.UnsupportedEncodingException;

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;

/**
 * 解密
 * @author 张超
 *
 */
public final class Decrypt {

    /**
     * 先验证token是否被伪造，然后解码token。
     * @param token 字符串token
     * @return 解密后的DecodedJWT对象，可以读取token中的数据。
     */
    public DecodedJWT deToken(final String token) {
        DecodedJWT jwt = null;
        try {
            // 使用了HMAC256加密算法。
            // mysecret是用来加密数字签名的密钥。
            JWTVerifier verifier = JWT.require(Algorithm.HMAC256("mysecret"))
                .withIssuer("auth0")
                .build(); //Reusable verifier instance
            jwt = verifier.verify(token);
        } catch (JWTVerificationException exception){
            //Invalid signature/claims
            exception.printStackTrace();
        } catch (IllegalArgumentException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return jwt;
    }
}

Main.java

package zhangchao;

import com.auth0.jwt.interfaces.DecodedJWT;

public class Main {

    public static void main(String[] args) {
        // 生成token
        Encrypt encrypt = new Encrypt();
        String token = encrypt.getToken(true, "zhangchao", "张超");

        // 打印token
        System.out.println("token: " + token);

        // 解密token
        Decrypt decrypt = new Decrypt();
        DecodedJWT jwt = decrypt.deToken(token);

        System.out.println("issuer: " + jwt.getIssuer());
        System.out.println("isVip:  " + jwt.getClaim("isVip").asBoolean());
        System.out.println("username: " + jwt.getClaim("username").asString());
        System.out.println("name:     " + jwt.getClaim("name").asString());
        System.out.println("过期时间：      " + jwt.getExpiresAt());

    }

}