streamfile.java

hadoop:Nutch集群平台

/**
 * Copyright 2005 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.hadoop.dfs;


import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import java.net.*;
import org.apache.hadoop.dfs.*;
import org.apache.hadoop.fs.*;
import org.apache.hadoop.io.*;
import org.apache.hadoop.conf.*;
import java.text.DateFormat;

public class StreamFile extends HttpServlet {

  static InetSocketAddress nameNodeAddr;
  static DataNode datanode = null;
  static Configuration conf = new Configuration();
  Random rand = new Random();
  static {
    if ((datanode = DataNode.getDataNode()) != null) {
      nameNodeAddr = datanode.getNameNodeAddr();
    }
  }
  public void doGet(HttpServletRequest request, HttpServletResponse response)
                                     throws ServletException, IOException {
    String filename = request.getParameter("filename");
    if (filename == null || filename.length() == 0) {
      response.setContentType("text/plain");
      PrintWriter out = response.getWriter();
      out.print("Invalid input");
      return;
    }
    DFSClient dfs = new DFSClient(nameNodeAddr, conf);
    FSInputStream in = dfs.open(new UTF8(filename));
    OutputStream os = response.getOutputStream();
    response.setHeader("Content-Disposition", "attachment; filename=\"" + 
                        filename + "\"");
    response.setContentType("application/octet-stream");
    byte buf[] = new byte[4096];
    try {
      int bytesRead;
      while ((bytesRead = in.read(buf)) != -1) {
        os.write(buf, 0, bytesRead);
      }
    } finally {
      in.close();
      os.close();
      dfs.close();
    }
  }
}