package com.example.chat.jwt;

import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.interfaces.DecodedJWT;
import org.springframework.stereotype.Component;


public class JWTUtil {
    private static final String tokenPassword = "uziCjb";
    public static String sign(String username) {//用用户名作为被加密的对象
        String token;

        token = JWT.create()//生成jwt令牌，加密过程
                .withIssuer("llh")
                .withClaim("username", username)
                .sign(Algorithm.HMAC256(tokenPassword));
        return token;//返回加密后的token
    }
    public static String verify(String token){
        JWTVerifier jwtVerifier=JWT.require(Algorithm.HMAC256(tokenPassword)).withIssuer("llh").build();//构建一个jwt解码器
        DecodedJWT jwtToken=jwtVerifier.verify(token);//解码
        if(token.isEmpty()){//若token为空则返回false拦截
            return null;
        }
        else {
            System.out.println("认证通过：");
            System.out.println("issuer: " + jwtToken.getIssuer());
            System.out.println("username: " + jwtToken.getClaim("username").asString());
            return jwtToken.getClaim("username").asString();
        }
    }
}