/*
* 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.
*/
package org.springframework.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.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;
/**
* Convenient superclass for Excel document views.
*
* <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>
* protected void buildExcelDocument(
* Map 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("Spring");
* sheet.setDefaultColumnWidth(12);
*
* // Write a text at A1.
* HSSFCell cell = getCell(sheet, 0, 0);
* setText(cell, "Spring 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;
}
protected boolean generatesDownloadContent() {
return true;
}
/**
* Renders the Excel view, given the specified model.
*/
protected final void renderMergedOutputModel(
Map 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.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);
}
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 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);
}
}