使用Java解析Torrent文件（BT种子），基于使用Eclipse ECF中的org.eclipse.bittorrent方案-进城务工人员小梅

在Java中，当需要解析BT种子文件（Torrent）时，一种方案是使用Eclipse ECF中的org.eclipse.bittorrent。
Torrent是一个使用BEncoding的Dictionary，具体可以查看BEP的相关文档（BEP0003），在此不再赘述。org.eclipse.bittorrent的使用非常简单，但由于其出现的年代已经比较久远，因此其缺点之一就在于解析的是一个Torrent文件的Metadata（参见BEP0009中的metadata一节），即the info-dictionary part of the .torrent file，而没有解析诸如announce等字段。

1、org.eclipse.bittorrent的文档

org.eclipse.bittorrent是Eclipse ECF中的一个插件（这个ECF好像历史也比较久远了），在Elipse官网上可以找到org.eclipse.bittorrent的官方文档。我们所关注的主要是类

org.eclipse.ecf.protocol.bittorrent.TorrentFile，其方法主要包括：

Method Summary
`boolean`	`equals(java.lang.Object other)` Returns whether this `TorrentFile` is equal to the given object.
`java.lang.String[]`	`getFilenames()` Retrieves the names of all of the files’ that is specified by this `Torrent`.
`java.lang.String`	`getHexHash()` Returns the hexadecimal representation of the hash returned from `getInfoHash()`.
`java.lang.String`	`getInfoHash()` Returns the hash of the `info` dictionary specified by the torrent’s metainfo.
`long[]`	`getLengths()` Retrieve the specified lengths of the files contained within this torrent.
`java.lang.String`	`getName()` Retrieves the name of this torrent file.
`int`	`getNumPieces()` Returns the number of pieces associated with this torrent.
`int`	`getPieceLength()` Returns the length of a piece.
`java.lang.String[]`	`getPieces()` Returns a string array that contains the SHA-1 hash of each of the pieces defined by the torrent’s metainfo.
`java.io.File`	`getTargetFile()` Gets the file that has been set as the target file of this torrent per `setTargetFile(File)`.
`long`	`getTotalLength()` Retrieves the total length of all of the files specified within this torrent.
`java.lang.String`	`getTracker()` Retrieves the URL of the tracker that’s handling the requests for this torrent.
`int`	`hashCode()` Returns the hash code of this `TorrentFile` based on its info hash.
`boolean`	`isMultiFile()` Returns whether this torrent is associated with multiple files or not.
`void`	`save(java.io.File file)` Writes the contents of the file that was used to initialize this `TorrentFile` onto the provided file.
`void`	`setTargetFile(java.io.File file)` Sets the target file or folder that this torrent should download to or look for the corresponding files in.
`boolean`	`validate()` Checks the integrity of the target file or folder as set by `setTargetFile(File)` to determine whether its contents pass all of the hash checks.