Java tutorial
/* * Copyright 2010 Manuel Carrasco Moino. (manolo at apache/org) * http://code.google.com/p/gwtupload * * 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 gwtupload.server; import static gwtupload.shared.UConsts.TAG_CANCELED; import static gwtupload.shared.UConsts.TAG_ERROR; import gwtupload.server.exceptions.UploadActionException; import gwtupload.server.exceptions.UploadCanceledException; import gwtupload.shared.UConsts; import java.io.IOException; import java.io.InputStream; import java.util.HashMap; import java.util.List; import java.util.Map; import javax.servlet.ServletConfig; import javax.servlet.ServletContext; import javax.servlet.ServletException; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.fileupload.FileItem; /** * <p>Class used to manipulate the data received in the server side.</p> * * The user has to implement the method executeAction which receives the list of the FileItems * sent to the server. Each FileItem represents a file or a form field. * * <p>Note: Temporary files are not deleted until the user calls removeSessionFiles(request).</p> * * @author Manolo Carrasco Moino * */ public class UploadAction extends UploadServlet { private static final long serialVersionUID = -6790246163691420791L; private boolean removeSessionFiles = false; private boolean removeData = false; @Override public void init(ServletConfig config) throws ServletException { super.init(config); ServletContext ctx = config.getServletContext(); removeSessionFiles = Boolean.valueOf(ctx.getInitParameter("removeSessionFiles")); removeData = Boolean.valueOf(ctx.getInitParameter("removeData")); logger.info("UPLOAD-ACTION init: removeSessionFiles=" + removeSessionFiles + ", removeData=" + removeData); } /** * Returns the content of a file as an InputStream if it is found in the * FileItem vector. * * @param sessionFiles collection of files sent by the client * @param parameter field name or file name of the desired file * @return an ImputString */ public static InputStream getFileStream(List<FileItem> sessionFiles, String parameter) throws IOException { FileItem item = findFileItem(sessionFiles, parameter); return item == null ? null : item.getInputStream(); } /** * Returns the value of a text field present in the FileItem collection. * * @param sessionFiles collection of fields sent by the client * @param fieldName field name * @return the string value */ public static String getFormField(List<FileItem> sessionFiles, String fieldName) { FileItem item = findItemByFieldName(sessionFiles, fieldName); return item == null || item.isFormField() == false ? null : item.getString(); } /** * This method is called when all data is received in the server. * * Temporary files are not deleted until the user calls removeSessionFileItems(request) * * Override this method to customize the behavior * * @param request * @param sessionFiles * * @return the text/html message to be sent to the client. * In the case of null the standard response configured for this * action will be sent. * * @throws UploadActionException * In the case of error * */ public String executeAction(HttpServletRequest request, List<FileItem> sessionFiles) throws UploadActionException { return null; } /** * This method is called when a received file is requested to be removed and * is in the collection of items stored in session. * If the item does't exist in session this method is not called * * After it, the item is removed from the session items collection. * * Override this method to customize the behavior * * @param request * @param item The item in session * * @throws UploadActionException * In the case of an error, the exception message is returned to * the client and the item is not deleted from session * */ public void removeItem(HttpServletRequest request, FileItem item) throws UploadActionException { } /** * This method is called when a received file is requested to be removed. * After it, the item is removed from the session items collection. * * Override this method to customize the behavior * * @param request * @param fieldName The name of the filename input * * @throws UploadActionException * In the case of an error, the exception message is returned to * the client and the item is not deleted from session * */ public void removeItem(HttpServletRequest request, String fieldName) throws UploadActionException { } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { String parameter = request.getParameter(UConsts.PARAM_REMOVE); if (parameter != null) { try { // Notify classes extending this that they have to remove the item. removeItem(request, parameter); // Other way to notify classes extending this. FileItem item = super.findFileItem(getMySessionFileItems(request), parameter); if (item != null) { removeItem(request, item); } } catch (Exception e) { renderXmlResponse(request, response, "<" + TAG_ERROR + ">" + e.getMessage() + "</" + TAG_ERROR + ">"); return; } // Remove the item saved in session in the case it was not removed yet super.removeUploadedFile(request, response); } else { super.doGet(request, response); } } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { String error = null; String message = null; Map<String, String> tags = new HashMap<String, String>(); perThreadRequest.set(request); try { // Receive the files and form elements, updating the progress status error = super.parsePostRequest(request, response); if (error == null) { // Fill files status before executing user code which could remove session files getFileItemsSummary(request, tags); // Call to the user code message = executeAction(request, getMyLastReceivedFileItems(request)); } } catch (UploadCanceledException e) { renderXmlResponse(request, response, "<" + TAG_CANCELED + ">true</" + TAG_CANCELED + ">"); return; } catch (UploadActionException e) { logger.info("ExecuteUploadActionException when receiving a file.", e); error = e.getMessage(); } catch (Exception e) { logger.info("Unknown Exception when receiving a file.", e); error = e.getMessage(); } finally { perThreadRequest.set(null); } String postResponse = null; AbstractUploadListener listener = getCurrentListener(request); if (error != null) { postResponse = "<" + TAG_ERROR + ">" + error + "</" + TAG_ERROR + ">"; renderXmlResponse(request, response, postResponse); if (listener != null) { listener.setException(new RuntimeException(error)); } UploadServlet.removeSessionFileItems(request); } else { // GWT??RO? by xiewz 2017.8.29 String uploadType = request.getHeader("UploadType"); if (uploadType != null && !uploadType.trim().isEmpty() && message != null) { renderMessage(response, message, "text/plain"); } else { // ? if (message != null) { // see issue #139 tags.put("message", "<![CDATA[" + message + "]]>"); } postResponse = statusToString(tags); renderXmlResponse(request, response, postResponse, true); } } finish(request, postResponse); if (removeSessionFiles) { removeSessionFileItems(request, removeData); } } }