FastDFS的配置、部署与API使用解读（3）以流的方式上传文件的客户端代码

调用的API为：

String[] upload_file(

String group_name,//组名，不指定则可设为null

long file_size,//文件大小，必须制定

UploadCallback callback,//回调

String file_ext_name,

NameValuePair[] meta_list

)

 /**
  * Upload File to DFS, directly transferring java.io.InputStream to java.io.OutStream
  * @author Poechant
  * @email [email protected]
  * @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[] uploadFileByStream(InputStream inStream, String uploadFileName, long fileLength) throws IOException {

     String[] results = null;
     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 results;
     }

     TrackerClient tracker = new TrackerClient();
        TrackerServer trackerServer = tracker.getConnection();
        StorageServer storageServer = null;
        StorageClient1 client = new StorageClient1(trackerServer, storageServer);

        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));

        try {
         // results[0]: groupName, results[1]: remoteFilename.
         results = client.upload_file(null, fileLength, new UploadFileSender(inStream), fileExtName, metaList);
     } catch (Exception e) {
         logger.warn("Upload file \"" + uploadFileName + "\"fails");
     }

         trackerServer.close();

     return results;
 }

其中的UploadFileSender是一个实现了UploadCallback接口的类：

 private static class UploadFileSender implements UploadCallback {

     private InputStream inStream;

     public UploadFileSender(InputStream inStream) {
         this.inStream = inStream;
     }

     public int send(OutputStream out) throws IOException {
         int readBytes;
         while((readBytes = inStream.read()) > 0) {
             out.write(readBytes);
         }
         return 0;
     }
 }