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FastDFS的配置、部署与API使用解读（2）以字节方式上传文件的客户端代码

2024-08-05 17:18:38   220人阅读

1、下载FastDFS的API FastDFS提供Java和PHP等语言的客户端API。可以到FastDFS在Google Code的项目主页 http://code.google.com/p/fastdfs/downloads/list 下载。本文以Java API为例。
2、调用API的上传接口 通过Servlet得到InputStream、文件名称和文件长度，然后通过调用FastDFS提供的Java API把文件上传到FastDFS服务器。下段代码中的getFileBuffer可参考本博客上一篇博文。（by Poechant）

[java] view plaincopyprint?
  1. /**
  2. * Upload File to DFS.
  3. * @param fileBuff, file to be uploaded.
  4. * @param uploadFileName, the name of the file.
  5. * @param fileLength, the length of the file.
  6. * @return the file ID in DFS.
  7. * @throws IOException
  8. */ 
  9. public String uploadFile(InputStream inStream, String uploadFileName, long fileLength) throws IOException { 
  10.     byte[] fileBuff = getFileBuffer(inStream, fileLength); 
  11.     String fileId = ""; 
  12.     String fileExtName = ""; 
  13.     if (uploadFileName.contains(".")) { 
  14.         fileExtName = uploadFileName.substring(uploadFileName.lastIndexOf(".") + 1); 
  15.     } else { 
  16.         logger.warn("Fail to upload file, because the format of filename is illegal."); 
  17.         return fileId; 
  18.     } 
  19.  
  20.  
  21.     //建立连接 
  22.     TrackerClient tracker = new TrackerClient(); 
  23.     TrackerServer trackerServer = tracker.getConnection(); 
  24.     StorageServer storageServer = null; 
  25.     StorageClient1 client = new StorageClient1(trackerServer, storageServer); 
  26.  
  27.  
  28.     //设置元信息 
  29.     NameValuePair[] metaList = new NameValuePair[3]; 
  30.     metaList[0] = new NameValuePair("fileName", uploadFileName); 
  31.     metaList[1] = new NameValuePair("fileExtName", fileExtName); 
  32.     metaList[2] = new NameValuePair("fileLength", String.valueOf(fileLength)); 
  33.  
  34.  
  35.     //上传文件 
  36.     try { 
  37.         fileId = client.upload_file1(fileBuff, fileExtName, metaList); 
  38.     } catch (Exception e) { 
  39.         logger.warn("Upload file \"" + uploadFileName + "\"fails"); 
  40.     } 
  41.     trackerServer.close(); 
  42.     return fileId; 
  43. }  
/** * Upload File to DFS. * @param fileBuff, file to be uploaded. * @param uploadFileName, the name of the file. * @param fileLength, the length of the file. * @return the file ID in DFS. * @throws IOException  */public String uploadFile(InputStream inStream, String uploadFileName, long fileLength) throws IOException {	byte[] fileBuff = getFileBuffer(inStream, fileLength);	String fileId = "";	String fileExtName = "";	if (uploadFileName.contains(".")) {		fileExtName = uploadFileName.substring(uploadFileName.lastIndexOf(".") + 1);	} else {		logger.warn("Fail to upload file, because the format of filename is illegal.");		return fileId;	}	//建立连接	TrackerClient tracker = new TrackerClient();	TrackerServer trackerServer = tracker.getConnection();	StorageServer storageServer = null;	StorageClient1 client = new StorageClient1(trackerServer, storageServer);	//设置元信息	NameValuePair[] metaList = new NameValuePair[3];	metaList[0] = new NameValuePair("fileName", uploadFileName);	metaList[1] = new NameValuePair("fileExtName", fileExtName);	metaList[2] = new NameValuePair("fileLength", String.valueOf(fileLength));	//上传文件	try {		fileId = client.upload_file1(fileBuff, fileExtName, metaList);	} catch (Exception e) {		logger.warn("Upload file \"" + uploadFileName + "\"fails");	}	trackerServer.close();	return fileId;}

3、调用方式详解 （1）客户端与Tracker Server通信 根据《FastDFS的配置、部署与API使用解读（1）Get Started with FastDFS》一文中提供的FastDFS的工作原理，结合上面的代码，首先通过TrackerClient构造函数从全局配置中获取Tracker Servers的IP和端口初始化一个TrackerClient对象tracker，并与其建立连接，我们可以从API的源码中看到：

[java] view plaincopyprint?
  1. /**
  2. * constructor with global tracker group
  3. */ 
  4. public TrackerClient() 
  5. { 
  6.     this.tracker_group = ClientGlobal.g_tracker_group; 
  7. }    
  8. /**
  9. * constructor with specified tracker group
  10. * @param tracker_group the tracker group object
  11. */ 
  12. public TrackerClient(TrackerGroup tracker_group) 
  13. { 
  14.     this.tracker_group = tracker_group; 
  15. } 
/*** constructor with global tracker group*/public TrackerClient(){	this.tracker_group = ClientGlobal.g_tracker_group;}	/*** constructor with specified tracker group* @param tracker_group the tracker group object*/public TrackerClient(TrackerGroup tracker_group){	this.tracker_group = tracker_group;}

?上述代码中ClientGlobal是一个提供很多静态成员供外部读取的类。通过tracker这个TrackerClient建立的与Tracker Server的连接，实例化了一个trackerServer对象。

 

（2）客户端与Storage Server通信

通过trackerServer取得某一个可用的Storage Server的地址并用其实例化一个StorageClient1对象。这样就完成了FastDFS的客户端调用上传、下载、删除等所有操作的前期建立连接的工作。
（3）调用文件操作API 这些操作包括upload、download、append、delete等。上例中提供的是上传的实例。

FastDFS的配置、部署与API使用解读（2）以字节方式上传文件的客户端代码


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