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

louyaoluan

　　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?

• /**
  
• * 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;  
  
• }
  

/**
* 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?

• /**
  
• * 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;  
  
• }
  

/**
* 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。