/*
* 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.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.write.WritableWorkbook;
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>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
*/
public abstract class AbstractJExcelView 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";
/** 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 AbstractJExcelView() {
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();
WritableWorkbook workbook;
if (this.url != null) {
Workbook template = getTemplateSource(this.url, request);
workbook = Workbook.createWorkbook(out, template);
}
else {
logger.debug("Creating Excel Workbook from scratch");
workbook = Workbook.createWorkbook(out);
}
buildExcelDocument(model, workbook, request, response);
// Should we set the content length here?
// response.setContentLength(workbook.getBytes().length);
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;
}
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