Java tutorial
/*********************************************************************************************************************** * Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu) * * 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 eu.stratosphere.client.web; import java.io.File; import java.io.IOException; import java.io.PrintWriter; import java.util.Arrays; import java.util.Comparator; import java.util.GregorianCalendar; import java.util.Iterator; import java.util.List; import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.fileupload.FileItem; import org.apache.commons.fileupload.FileUploadException; import org.apache.commons.fileupload.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; /** * A servlet that accepts uploads of pact programs, returns a listing of the * directory containing the job jars, and deleting these jars. */ public class JobsServlet extends HttpServlet { /** * Serial UID for serialization interoperability. */ private static final long serialVersionUID = -1373210261957434273L; // ------------------------------------------------------------------------ private static final String ACTION_PARAM_NAME = "action"; private static final String ACTION_LIST_VALUE = "list"; private static final String ACTION_DELETE_VALUE = "delete"; private static final String FILENAME_PARAM_NAME = "filename"; private static final String CONTENT_TYPE_PLAIN = "text/plain"; private static final Comparator<File> FILE_SORTER = new Comparator<File>() { @Override public int compare(File o1, File o2) { return o1.getName().compareTo(o2.getName()); } }; // ------------------------------------------------------------------------ /** * The file object for the directory for temporary files. */ private final File tmpDir; /** * The file object for the directory for the submitted jars. */ private final File destinationDir; /** * The name of the file to redirect to after the upload. */ private final String targetPage; // ------------------------------------------------------------------------ /** * Creates a new <tt>JobServlet</tt>, configured with the given directories * and the given result page. * * @param jobsDir * The directory to store uploaded jobs in. * @param tmpDir * The directory for temporary files. * @param targetPage * The page to redirect to after a successful upload. */ public JobsServlet(File jobsDir, File tmpDir, String targetPage) { this.tmpDir = tmpDir; this.destinationDir = jobsDir; this.targetPage = targetPage; } // ------------------------------------------------------------------------ public void init(ServletConfig config) throws ServletException { super.init(config); if (!(tmpDir.isDirectory() && tmpDir.canWrite())) { throw new ServletException(tmpDir.getAbsolutePath() + " is not a writable directory"); } if (!(destinationDir.isDirectory() && destinationDir.canWrite())) { throw new ServletException(destinationDir.getAbsolutePath() + " is not a writable directory"); } } @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String action = req.getParameter(ACTION_PARAM_NAME); if (action.equals(ACTION_LIST_VALUE)) { GregorianCalendar cal = new GregorianCalendar(); File[] files = destinationDir.listFiles(); Arrays.<File>sort(files, FILE_SORTER); resp.setStatus(HttpServletResponse.SC_OK); resp.setContentType(CONTENT_TYPE_PLAIN); PrintWriter writer = resp.getWriter(); for (int i = 0; i < files.length; i++) { if (!files[i].getName().endsWith(".jar")) { continue; } cal.setTimeInMillis(files[i].lastModified()); writer.println(files[i].getName() + '\t' + (cal.get(GregorianCalendar.MONTH) + 1) + '/' + cal.get(GregorianCalendar.DAY_OF_MONTH) + '/' + cal.get(GregorianCalendar.YEAR) + ' ' + cal.get(GregorianCalendar.HOUR_OF_DAY) + ':' + cal.get(GregorianCalendar.MINUTE) + ':' + cal.get(GregorianCalendar.SECOND)); } } else if (action.equals(ACTION_DELETE_VALUE)) { String filename = req.getParameter(FILENAME_PARAM_NAME); if (filename == null || filename.length() == 0) { resp.setStatus(HttpServletResponse.SC_BAD_REQUEST); } else { File f = new File(destinationDir, filename); if (!f.exists() || f.isDirectory()) { resp.setStatus(HttpServletResponse.SC_NOT_FOUND); } f.delete(); resp.setStatus(HttpServletResponse.SC_OK); } } else { resp.setStatus(HttpServletResponse.SC_BAD_REQUEST); } } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { // check, if we are doing the right request if (!ServletFileUpload.isMultipartContent(req)) { resp.sendError(HttpServletResponse.SC_BAD_REQUEST); return; } // create the disk file factory, limiting the file size to 20 MB DiskFileItemFactory fileItemFactory = new DiskFileItemFactory(); fileItemFactory.setSizeThreshold(20 * 1024 * 1024); // 20 MB fileItemFactory.setRepository(tmpDir); String filename = null; // parse the request ServletFileUpload uploadHandler = new ServletFileUpload(fileItemFactory); try { @SuppressWarnings("unchecked") Iterator<FileItem> itr = ((List<FileItem>) uploadHandler.parseRequest(req)).iterator(); // go over the form fields and look for our file while (itr.hasNext()) { FileItem item = itr.next(); if (!item.isFormField()) { if (item.getFieldName().equals("upload_jar_file")) { // found the file, store it to the specified location filename = item.getName(); File file = new File(destinationDir, filename); item.write(file); break; } } } } catch (FileUploadException ex) { resp.sendError(HttpServletResponse.SC_NOT_ACCEPTABLE, "Invalid Fileupload."); return; } catch (Exception ex) { resp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "An unknown error occurred during the file upload."); return; } // write the okay message resp.sendRedirect(targetPage); } }