PEM格式中带有换行符,处理时需要注意,此时连接的字符串就位私钥

代码

package com.mio.mqtt.util;

import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import sun.misc.BASE64Decoder;


import java.security.KeyFactory;
import java.security.spec.KeySpec;
import java.security.spec.PKCS8EncodedKeySpec;
import java.time.Instant;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

public class JWTUtils {
    public static void main(String[] args) {
        Instant now = Instant.now();

        Map<String, Object> claims = new HashMap<>();
        claims.put("user", "mqtt-client");

        String privateKey = "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";


        try {

            // 获取秘钥
            BASE64Decoder base64Decoder=new BASE64Decoder();
            byte[] bytes = base64Decoder.decodeBuffer(privateKey);
            KeySpec spec = new PKCS8EncodedKeySpec(bytes);
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");


            String compact = Jwts.builder()
                    .setClaims(claims) // 自定义声明
                    .setIssuedAt(Date.from(now)) // 对标准中的声明赋值,设置签发时间
                    .setExpiration(Date.from(now.plusSeconds(1000))) // 对标准中的声明赋值,设置过期时间
                    .signWith(SignatureAlgorithm.RS256, keyFactory.generatePrivate(spec)) // 设置签名
                    .compact();
            System.out.println(compact);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}