Java tutorial
/* * Copyright 2008-2010 biaoping.yin * * 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.frameworkset.web.servlet.view.document; import java.util.Locale; import java.util.Map; import javax.servlet.ServletOutputStream; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.poi.hssf.usermodel.HSSFCell; import org.apache.poi.hssf.usermodel.HSSFRow; import org.apache.poi.hssf.usermodel.HSSFSheet; import org.apache.poi.hssf.usermodel.HSSFWorkbook; import org.apache.poi.poifs.filesystem.POIFSFileSystem; import org.frameworkset.spi.support.LocalizedResourceHelper; import org.frameworkset.util.io.Resource; import org.frameworkset.web.servlet.support.RequestContextUtils; import org.frameworkset.web.servlet.view.AbstractView; /** * Convenient superclass for Excel document views. * Compatible with Apache POI 3.0 as well as 3.5, as of bboss. * * <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://jakarta.apache.org/poi/index.html">Jakarta's POI site</a> * * <p>As an example, you can try this snippet: * * <pre class="code"> * protected void buildExcelDocument( * Map<String, Object> model, HSSFWorkbook workbook, * HttpServletRequest request, HttpServletResponse response) { * * // Go to the first sheet. * // getSheetAt: only if workbook is created from an existing document * // HSSFSheet sheet = workbook.getSheetAt(0); * HSSFSheet sheet = workbook.createSheet("Bboss"); * sheet.setDefaultColumnWidth(12); * * // Write a text at A1. * HSSFCell cell = getCell(sheet, 0, 0); * setText(cell, "Bboss POI test"); * * // Write the current date at A2. * HSSFCellStyle dateStyle = workbook.createCellStyle(); * dateStyle.setDataFormat(HSSFDataFormat.getBuiltinFormat("m/d/yy")); * cell = getCell(sheet, 1, 0); * cell.setCellValue(new Date()); * cell.setCellStyle(dateStyle); * * // Write a number at A3 * getCell(sheet, 2, 0).setCellValue(458); * * // Write a range of numbers. * HSSFRow sheetRow = sheet.createRow(3); * for (short i = 0; i < 10; i++) { * sheetRow.createCell(i).setCellValue(i * 10); * } * }</pre> * * This class is similar to the AbstractPdfView class in usage style. * * @author Jean-Pierre Pawlak * @author Juergen Hoeller * @see AbstractPdfView */ public abstract class AbstractExcelView extends AbstractView { /** 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"; private String url; /** * Default Constructor. * Sets the content type of the view to "application/vnd.ms-excel". */ public AbstractExcelView() { 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 { HSSFWorkbook workbook; if (this.url != null) { workbook = getTemplateSource(this.url, request); } else { workbook = new HSSFWorkbook(); logger.debug("Created Excel Workbook from scratch"); } buildExcelDocument(model, workbook, request, response); // Set the content type. response.setContentType(getContentType()); // Should we set the content length here? // response.setContentLength(workbook.getBytes().length); // Flush byte array to servlet output stream. ServletOutputStream out = response.getOutputStream(); workbook.write(out); out.flush(); } /** * Creates 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 HSSFWorkbook * @throws Exception in case of failure */ protected HSSFWorkbook getTemplateSource(String url, HttpServletRequest request) throws Exception { LocalizedResourceHelper helper = new LocalizedResourceHelper(getApplicationContext()); Locale userLocale = RequestContextUtils.getRequestContextLocal(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); } POIFSFileSystem fs = new POIFSFileSystem(inputFile.getInputStream()); return new HSSFWorkbook(fs); } /** * Subclasses must implement this method to create an Excel HSSFWorkbook 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. */ protected abstract void buildExcelDocument(Map<String, Object> model, HSSFWorkbook workbook, HttpServletRequest request, HttpServletResponse response) throws Exception; /** * Convenient method to obtain the cell in the given sheet, row and column. * <p>Creates the row and the cell if they still doesn't already exist. * Thus, the column can be passed as an int, the method making the needed downcasts. * @param sheet a sheet object. The first sheet is usually obtained by workbook.getSheetAt(0) * @param row thr row number * @param col the column number * @return the HSSFCell */ protected HSSFCell getCell(HSSFSheet sheet, int row, int col) { HSSFRow sheetRow = sheet.getRow(row); if (sheetRow == null) { sheetRow = sheet.createRow(row); } HSSFCell cell = sheetRow.getCell((short) col); if (cell == null) { cell = sheetRow.createCell((short) col); } return cell; } /** * Convenient method to set a String as text content in a cell. * @param cell the cell in which the text must be put * @param text the text to put in the cell */ protected void setText(HSSFCell cell, String text) { cell.setCellType(HSSFCell.CELL_TYPE_STRING); cell.setCellValue(text); } }