jwtUtils顧名思意

package com.pipihao.blog.util;
import java.util.Date;
  
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
  
import org.apache.commons.codec.binary.Base64;
  
import com.alibaba.fastjson.JSONObject;
import io.jsonwebtoken.Claims;
import io.jsonwebtoken.ExpiredJwtException;
import io.jsonwebtoken.JwtBuilder;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.MalformedJwtException;
import io.jsonwebtoken.SignatureAlgorithm;
import io.jsonwebtoken.SignatureException;
import io.jsonwebtoken.UnsupportedJwtException;
  
/**
 * JWTUtils工具類，生成jwt和解析jwt
 * JSON WEB TOKEN 結構組成：
 * (1)Header(頭部)：包含加密算法，通常直接使用 HMAC SHA256
 * (2)Payload(負載)：存放有效信息，比如消息體、簽發者、過期時間、簽發時間等
 * (3)Signature(簽名)：由header(base64后的)+payload(base64后的)+secret(秘鑰)三部分組合，然后通過head中聲明的算法進行加密
 * @author sixmonth
 * @date 2019年3月20日
 *
 */
public class JWTUtils {
     
    static String SECRETKEY = "KJHUhjjJYgYUllVbXhKDHXhkSyHjlNiVkYzWTBac1Yxkjhuad";
  
    /**
     * 由字符串生成加密key
     * @return
     */
    public static SecretKey generalKey(String stringKey) {
        byte[] encodedKey = Base64.decodeBase64(stringKey);
        SecretKey key = new SecretKeySpec(encodedKey, 0, encodedKey.length, "AES");
        return key;
    }
  
    /**
     * 創建jwt
     * @param uuid 唯一id，uuid即可
     * @param subject json形式字符串或字符串，增加用戶非敏感信息存儲，如用戶id或用戶賬號，與token解析后進行對比，防止亂用
     * @param expirationDate  生成jwt的有效期，單位秒
     * @return jwt token
     * @throws Exception
     */
    public static String createJWT(String uuid, String subject, long expirationDate) throws Exception {
        SignatureAlgorithm signatureAlgorithm = SignatureAlgorithm.HS256;
        long nowMillis = System.currentTimeMillis();
        Date now = new Date(nowMillis);
        SecretKey key = generalKey(SECRETKEY);
        JwtBuilder builder = Jwts.builder().setIssuer("").setId(uuid).setIssuedAt(now).setSubject(subject)
                .signWith(signatureAlgorithm, key);
        if (expirationDate >= 0) {
            long expMillis = nowMillis + expirationDate*1000;
            Date exp = new Date(expMillis);
            builder.setExpiration(exp);
        }
        return builder.compact();
    }
  
    /**
     * 解密jwt，獲取實體
     * @param jwt
     */
    public static Claims parseJWT(String jwt) throws ExpiredJwtException, UnsupportedJwtException,
            MalformedJwtException, SignatureException, IllegalArgumentException {
        SecretKey key = generalKey(SECRETKEY);
        Claims claims = Jwts.parser().setSigningKey(key).parseClaimsJws(jwt).getBody();
        return claims;
    }
  
    /**
    * 實例演示
    */
    public static void main(String[] args) {
        try {
            JSONObject subject = new JSONObject(true);
            subject.put("tem", "哈哈哈");
            subject.put("userName", "sixmonth");
            String token = createJWT(UUIDUtils.getUUID(), subject.toJSONString(), 10);//10秒過期
            //System.out.println(token);
            Claims claims = parseJWT(token);
            System.out.println("解析jwt："+claims.getSubject());
            JSONObject tem = JSONObject.parseObject(claims.getSubject());
            System.out.println("獲取json對象內容："+tem.getString("userName"));   
            System.out.println(claims.getExpiration()+"///"+claims.getExpiration().getTime());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}