GetImageServlet.java
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上传日期:2018-01-08
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文件大小:3k
- /**
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements. See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership. The ASF licenses this file
- * to you 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.hdfs.server.namenode;
- import java.util.*;
- import java.io.*;
- import javax.servlet.ServletContext;
- import javax.servlet.ServletException;
- import javax.servlet.http.HttpServlet;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
- import org.apache.hadoop.util.StringUtils;
- /**
- * This class is used in Namesystem's jetty to retrieve a file.
- * Typically used by the Secondary NameNode to retrieve image and
- * edit file for periodic checkpointing.
- */
- public class GetImageServlet extends HttpServlet {
- private static final long serialVersionUID = -7669068179452648952L;
- @SuppressWarnings("unchecked")
- public void doGet(HttpServletRequest request,
- HttpServletResponse response
- ) throws ServletException, IOException {
- Map<String,String[]> pmap = request.getParameterMap();
- try {
- ServletContext context = getServletContext();
- FSImage nnImage = (FSImage)context.getAttribute("name.system.image");
- TransferFsImage ff = new TransferFsImage(pmap, request, response);
- if (ff.getImage()) {
- // send fsImage
- TransferFsImage.getFileServer(response.getOutputStream(),
- nnImage.getFsImageName());
- } else if (ff.getEdit()) {
- // send edits
- TransferFsImage.getFileServer(response.getOutputStream(),
- nnImage.getFsEditName());
- } else if (ff.putImage()) {
- // issue a HTTP get request to download the new fsimage
- nnImage.validateCheckpointUpload(ff.getToken());
- TransferFsImage.getFileClient(ff.getInfoServer(), "getimage=1",
- nnImage.getFsImageNameCheckpoint());
- nnImage.checkpointUploadDone();
- }
- } catch (Exception ie) {
- String errMsg = "GetImage failed. " + StringUtils.stringifyException(ie);
- response.sendError(HttpServletResponse.SC_GONE, errMsg);
- throw new IOException(errMsg);
- } finally {
- response.getOutputStream().close();
- }
- }
- }