JWT是什么我就不做介绍了,在这只说一下JWT的开源的第三方JJWT的初步使用
话不多说,上代码
JwtUtil.class

public class JwtUtil 
{
    private String jianshu;
    
    /**
     * 由字符串生成加密key
     * @return
     */
    public SecretKey generalKey(){
        String stringKey = jianshu+Constant.JWT_SECRET;
        byte[] encodedKey = Base64.decodeBase64(stringKey);
        SecretKey key = new SecretKeySpec(encodedKey, 0, encodedKey.length, "AES");
        return key;
    }

    /**
     * 创建jwt
     * @param id
     * @param subject
     * @param ttlMillis
     * @return
     * @throws Exception
     */
    public String createJWT(String id, String subject, long ttlMillis) throws Exception {
        
        SignatureAlgorithm signatureAlgorithm = SignatureAlgorithm.HS256;
        long nowMillis = System.currentTimeMillis();
        Date now = new Date(nowMillis);
        SecretKey key = generalKey();
        JwtBuilder builder = Jwts.builder()
            .setId(id)
            .setIssuedAt(now)
            .setSubject(subject)
            .signWith(signatureAlgorithm, key);
        if (ttlMillis >= 0) {
            long expMillis = nowMillis + ttlMillis;
            Date exp = new Date(expMillis);
            builder.setExpiration(exp);
        }
        return builder.compact();
    }
    
    /**
     * 解密jwt
     * @param jwt
     * @return
     * @throws Exception
     */
    public Claims parseJWT(String jwt) throws Exception{
        SecretKey key = generalKey();
        Claims claims = Jwts.parser()         
           .setSigningKey(key)
           .parseClaimsJws(jwt).getBody();
        return claims;
    }
    
    /**
     * 生成subject信息
     * @param user
     * @return
     */
    public static String generalSubject(t_user user){
        JSONObject jo = new JSONObject();
        jo.put("userId", user.getId());
        jo.put("mobile", user.getMobile());
        return jo.toJSONString();
    }
    
}

Constant.class

public class Constant 
{
    /**
     * jwt
     * 
     */
    public static final String JWT_ID = "jwt";
    public static final String JWT_SECRET = "hong1mu2zhi3ruan4jian5";
    public static final int JWT_TTL = 60*60*1000;  //millisecond
    public static final int JWT_REFRESH_INTERVAL = 55*60*1000;  //millisecond
    public static final int JWT_REFRESH_TTL = 12*60*60*1000;  //millisecond
}

在这只是JJWT的最基本的实现,后续会继续完善.

点这里:JJWT的github地址
JJWT的jar包:jar包地址