完成部分资源功能
Change-Id: Idfaef80363ef191a294e52ae53cdd4e2b3e7ccef
diff --git a/src/main/java/com/pt/service/TorrentService.java b/src/main/java/com/pt/service/TorrentService.java
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+++ b/src/main/java/com/pt/service/TorrentService.java
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+package com.pt.service;
+
+import com.pt.entity.TorrentMeta;
+import com.pt.repository.TorrentMetaRepository;
+import com.pt.utils.BencodeUtils;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import java.io.*;
+import java.security.MessageDigest;
+import java.time.LocalDateTime;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+@Service
+public class TorrentService {
+
+ // Tracker 服务器的 announce 地址
+ private static final String ANNOUNCE_URL = "http://localhost:8080/announce";
+ private static final int PIECE_LENGTH = 256 * 1024;
+
+ @Autowired
+ private TorrentMetaRepository torrentMetaRepository;
+
+ public byte[] generateTorrentBytes(String sourceFilePath) throws Exception {
+ File sourceFile = new File(sourceFilePath);
+
+ // 构造 info 字典
+ Map<String, Object> infoDict = new LinkedHashMap<>();
+ infoDict.put("name", sourceFile.getName());
+ infoDict.put("length", sourceFile.length());
+ infoDict.put("piece length", PIECE_LENGTH);
+ infoDict.put("pieces", calcPiecesHashes(sourceFile));
+
+ // 构造完整 torrent 字典
+ Map<String, Object> torrentDict = new LinkedHashMap<>();
+ torrentDict.put("announce", ANNOUNCE_URL);
+ torrentDict.put("info", infoDict);
+
+ // 编码成种子数据字节数组
+ byte[] bencodedTorrent = BencodeUtils.encode(torrentDict);
+
+ // 计算 info_hash 并保存到数据库（如果需要的话）
+ MessageDigest sha1 = MessageDigest.getInstance("SHA-1");
+ byte[] infoEncoded = BencodeUtils.encode(infoDict);
+ sha1.update(infoEncoded);
+ String infoHash = bytesToHex(sha1.digest());
+
+ TorrentMeta meta = new TorrentMeta();
+ meta.setFilename(sourceFile.getName());
+ meta.setInfoHash(infoHash);
+ meta.setSize(sourceFile.length());
+ meta.setUploadTime(LocalDateTime.now());
+ torrentMetaRepository.save(meta);
+
+ return bencodedTorrent;
+ }
+
+
+ private byte[] calcPiecesHashes(File file) throws Exception {
+ MessageDigest sha1 = MessageDigest.getInstance("SHA-1");
+ try (InputStream fis = new FileInputStream(file)) {
+ byte[] buffer = new byte[PIECE_LENGTH];
+ ByteArrayOutputStream piecesBuffer = new ByteArrayOutputStream();
+
+ int read;
+ while ((read = fis.read(buffer)) > 0) {
+ sha1.reset();
+ sha1.update(buffer, 0, read);
+ piecesBuffer.write(sha1.digest());
+ }
+ return piecesBuffer.toByteArray();
+ }
+ }
+
+ private String bytesToHex(byte[] bytes) {
+ StringBuilder sb = new StringBuilder();
+ for (byte b : bytes) {
+ sb.append(String.format("%02x", b));
+ }
+ return sb.toString();
+ }
+}
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