前后端分离的Web应用程序中使用Spring Security+Mybatis+JWT非对称加密+动态权限管理（七）：生成令牌和读取令牌中的信息

package com.security;

import java.io.InputStream;
import java.security.KeyStore;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.util.Date;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;

public class JwtTokenUtils {
    //加载jwt.jks文件
    private static InputStream inputStream = Thread.currentThread().getContextClassLoader().getResourceAsStream("jwt.jks");
    private static PrivateKey privateKey = null;
    private static PublicKey publicKey = null;

    static {
        try {
            KeyStore keyStore = KeyStore.getInstance("JKS");
            keyStore.load(inputStream, "123456".toCharArray()); //123456是制作jwt.jks文件时输入的密码
            privateKey = (PrivateKey) keyStore.getKey("jwt", "123456".toCharArray());
            publicKey = keyStore.getCertificate("jwt").getPublicKey();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    public static String generateToken(String subject, int expirationSeconds) { //根据用户名(subject)和指定的有效时间生成令牌
        return Jwts.builder()
                .setClaims(null)
                .setSubject(subject)
                .setExpiration(new Date(System.currentTimeMillis() + expirationSeconds * 1000))
                .signWith(SignatureAlgorithm.RS256, privateKey)
                .compact();
    }

    public static String parseToken(String token) {  //从令牌中读取subject，即用户名
        String subject = null;
        try {
            Claims claims = Jwts.parser()
                    .setSigningKey(publicKey)
                    .parseClaimsJws(token).getBody();
            subject = claims.getSubject();
        } catch (Exception e) {
        }
        return subject;
    }

}