Java tutorial
package com.vh.ds.iam.web.front.jxl; /* * Copyright 2002-2008 the original author or authors. * * 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. */ import java.io.OutputStream; import java.util.Locale; import java.util.Map; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import jxl.Workbook; import jxl.WorkbookSettings; import jxl.write.WritableWorkbook; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.core.io.Resource; import org.springframework.core.io.support.LocalizedResourceHelper; import org.springframework.web.servlet.support.RequestContextUtils; import org.springframework.web.servlet.view.AbstractView; import org.springframework.web.servlet.view.document.AbstractExcelView; import org.springframework.web.servlet.view.document.AbstractPdfView; /** * Convenient superclass for Excel document views. * * <p>This class uses the <i>JExcelAPI</i> instead of <i>POI</i>. More * information on <i>JExcelAPI</i> can be found on their <a * href="http://www.andykhan.com/jexcelapi/" target="_blank">website</a>. * * <p>Properties: * <ul> * <li>url (optional): The url of an existing Excel document to pick as a * starting point. It is done without localization part nor the .xls extension. * </ul> * * <p>The file will be searched with locations in the following order: * <ul> * <li>[url]_[language]_[country].xls * <li>[url]_[language].xls * <li>[url].xls * </ul> * * <p>For working with the workbook in the subclass, see <a * href="http://www.andykhan.com/jexcelapi/">Java Excel API site</a> * * <p>As an example, you can try this snippet: * * <pre class="code"> * protected void buildExcelDocument( * Map<String, Object> model, WritableWorkbook workbook, * HttpServletRequest request, HttpServletResponse response) { * * if (workbook.getNumberOfSheets() == 0) { * workbook.createSheet("Spring", 0); * } * * WritableSheet sheet = workbook.getSheet("Spring"); * Label label = new Label(0, 0, "This is a nice label"); * sheet.addCell(label); * }</pre> * * The use of this view is close to the AbstractExcelView class, * just using the JExcel API instead of the Apache POI API. * * @author Bram Smeets * @author Alef Arendsen * @author Juergen Hoeller * @since 1.2.5 * @see AbstractExcelView * @see AbstractPdfView * * @see http://stackoverflow.com/questions/19663387/cant-get-proper-encoding-for-jexcel-jxl */ public abstract class AbstractJxlView extends AbstractView { protected static final Logger LOGGER = LoggerFactory.getLogger(AbstractJxlView.class); /** The content type for an Excel response */ private static final String CONTENT_TYPE = "application/vnd.ms-excel"; /** The extension to look for existing templates */ private static final String EXTENSION = ".xls"; /** The url at which the template to use is located */ private String url; /** * Default Constructor. * Sets the content type of the view to "application/vnd.ms-excel". */ public AbstractJxlView() { setContentType(CONTENT_TYPE); } /** * Set the URL of the Excel workbook source, without localization part nor extension. */ public void setUrl(String url) { this.url = url; } @Override protected boolean generatesDownloadContent() { return true; } /** * Renders the Excel view, given the specified model. */ @Override protected final void renderMergedOutputModel(Map<String, Object> model, HttpServletRequest request, HttpServletResponse response) throws Exception { // Set the content type and get the output stream. response.setContentType(getContentType()); OutputStream out = response.getOutputStream(); WorkbookSettings ws = new WorkbookSettings(); ws.setEncoding("Cp1252"); WritableWorkbook workbook; if (this.url != null) { Workbook template = getTemplateSource(this.url, request); workbook = Workbook.createWorkbook(out, template, ws); } else { LOGGER.debug("Creating Excel Workbook from scratch"); workbook = Workbook.createWorkbook(out, ws); } buildExcelDocument(model, workbook, request, response); workbook.write(); out.flush(); workbook.close(); } /** * Create the workbook from an existing XLS document. * @param url the URL of the Excel template without localization part nor extension * @param request current HTTP request * @return the template workbook * @throws Exception in case of failure */ protected Workbook getTemplateSource(String url, HttpServletRequest request) throws Exception { LocalizedResourceHelper helper = new LocalizedResourceHelper(getApplicationContext()); Locale userLocale = RequestContextUtils.getLocale(request); Resource inputFile = helper.findLocalizedResource(url, EXTENSION, userLocale); // Create the Excel document from the source. if (LOGGER.isDebugEnabled()) { LOGGER.debug("Loading Excel workbook from {}", inputFile); } return Workbook.getWorkbook(inputFile.getInputStream()); } /** * Subclasses must implement this method to create an Excel Workbook * document, given the model. * @param model the model Map * @param workbook the Excel workbook to complete * @param request in case we need locale etc. Shouldn't look at attributes. * @param response in case we need to set cookies. Shouldn't write to it. * @throws Exception in case of failure */ protected abstract void buildExcelDocument(Map<String, Object> model, WritableWorkbook workbook, HttpServletRequest request, HttpServletResponse response) throws Exception; }