spring5_demo1/spring5-auth/spring5-auth-client/src/main/java/com/yaozhitech/spring5/utils/JwtUtils.java

package com.yaozhitech.spring5.utils;

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

import org.apache.shiro.crypto.SecureRandomNumberGenerator;

import com.auth0.jwt.JWT;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.auth0.jwt.interfaces.DecodedJWT;

public class JwtUtils {

	/**
          * 获得token中的信息无需secret解密也能获得
     * @return token中包含的签发时间
     */
    public static Date getIssuedAt(String token) {
        try {
            DecodedJWT jwt = JWT.decode(token);
            return jwt.getIssuedAt();
        } catch (JWTDecodeException e) {
            return null;
        }
    }

    /**
     * 获得token中的信息无需secret解密也能获得
     * @return token中包含的用户名
     */
    public static String getUsername(String token) {
        try {
            DecodedJWT jwt = JWT.decode(token);
            return jwt.getClaim("username").asString();
        } catch (JWTDecodeException e) {
            return null;
        }
    }

    /**
     * 生成签名,expireTime后过期
     * @param username 用户名
     * @param time 过期时间s
     * @return 加密的token
     */
    public static String sign(String username, String salt, long time) {
        try {
            Date date = new Date(System.currentTimeMillis()+time*1000);
            Algorithm algorithm = Algorithm.HMAC256(salt);
            // 附带username信息
            return JWT.create()
                    .withClaim("username", username)
                    .withExpiresAt(date)
                    .withIssuedAt(new Date())
                    .sign(algorithm);
        } catch (UnsupportedEncodingException e) {
            return null;
        }
    }

    /**
     * token是否过期
     * @return true：过期
     */
    public static boolean isTokenExpired(String token) {
        Date now = Calendar.getInstance().getTime();
        DecodedJWT jwt = JWT.decode(token);
        return jwt.getExpiresAt().before(now);
    }

    /**
     * 生成随机盐,长度32位
     * @return
     */
    public static String generateSalt(){
        SecureRandomNumberGenerator secureRandom = new SecureRandomNumberGenerator();
        String hex = secureRandom.nextBytes(16).toHex();
        return hex;
    }
}