Java 对接卡密验证

// Java 卡密验证客户端（Java 8+）
import java.io.*;
import java.net.*;
import java.security.*;
import java.util.concurrent.*;

public class KamiClient {
    private final String baseUrl;
    private final String app;
    private final String signKey;

    public KamiClient(String userName, String app, String signKey) {
        this.baseUrl = "https://www.keyt.cn/kami/" + userName + "/check.php";
        this.app = app;
        this.signKey = signKey;
    }

    private String md5(String data) throws Exception {
        MessageDigest md = MessageDigest.getInstance("MD5");
        byte[] digest = md.digest(data.getBytes());
        StringBuilder sb = new StringBuilder();
        for (byte b : digest) sb.append(String.format("%02x", b));
        return sb.toString();
    }

    private String verifyResponse(String raw) throws Exception {
        if (!raw.contains("|sign=")) return null;
        String[] parts = raw.split("\\|sign=");
        String body = parts[0];
        String sign = parts[1];

        String localSign = md5(body + signKey);
        if (!localSign.equals(sign)) return null;

        int lastPipe = body.lastIndexOf('|');
        if (lastPipe == -1) return null;
        String tsStr = body.substring(lastPipe + 1);
        long ts = Long.parseLong(tsStr);
        long nowTs = System.currentTimeMillis() / 1000;
        if (Math.abs(nowTs - ts) > 120) return null;

        return body.substring(0, lastPipe);
    }

    public String verifyCard(String card, String mac) throws Exception {
        long ts = System.currentTimeMillis() / 1000;
        String url = baseUrl + "?card=" + card + "&mac=" + mac + "&app=" + app + "&heart=1&t=" + ts;
        
        HttpURLConnection conn = (HttpURLConnection) new URL(url).openConnection();
        BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        String raw = br.readLine();
        return verifyResponse(raw);
    }
}