org.springframework.web.servlet.view.jasperreports.AbstractJasperReportsSingleFormatView Maven / Gradle / Ivy
/*
* Copyright 2002-2014 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.jasperreports;
import java.io.ByteArrayOutputStream;
import java.util.Map;
import javax.servlet.http.HttpServletResponse;
import net.sf.jasperreports.engine.JasperPrint;
import org.springframework.ui.jasperreports.JasperReportsUtils;
import org.springframework.util.CollectionUtils;
import org.springframework.web.util.WebUtils;
/**
* Extends {@code AbstractJasperReportsView} to provide basic rendering logic
* for views that use a fixed format, e.g. always PDF or always HTML.
*
* Subclasses need to implement two template methods: {@code createExporter}
* to create a JasperReports exporter for a specific output format, and
* {@code useWriter} to determine whether to write text or binary content.
*
*
This class is compatible with classic JasperReports releases back until 2.x.
* As a consequence, it keeps using the {@link net.sf.jasperreports.engine.JRExporter}
* API which got deprecated as of JasperReports 5.5.2 (early 2014).
*
* @author Rob Harrop
* @author Juergen Hoeller
* @since 1.1.5
* @see #createExporter()
* @see #useWriter()
*/
@SuppressWarnings({"deprecation", "rawtypes"})
public abstract class AbstractJasperReportsSingleFormatView extends AbstractJasperReportsView {
@Override
protected boolean generatesDownloadContent() {
return !useWriter();
}
/**
* Perform rendering for a single Jasper Reports exporter, that is,
* for a pre-defined output format.
*/
@Override
@SuppressWarnings("unchecked")
protected void renderReport(JasperPrint populatedReport, Map model, HttpServletResponse response)
throws Exception {
net.sf.jasperreports.engine.JRExporter exporter = createExporter();
Map mergedExporterParameters = getConvertedExporterParameters();
if (!CollectionUtils.isEmpty(mergedExporterParameters)) {
exporter.setParameters(mergedExporterParameters);
}
if (useWriter()) {
renderReportUsingWriter(exporter, populatedReport, response);
}
else {
renderReportUsingOutputStream(exporter, populatedReport, response);
}
}
/**
* We need to write text to the response Writer.
* @param exporter the JasperReports exporter to use
* @param populatedReport the populated {@code JasperPrint} to render
* @param response the HTTP response the report should be rendered to
* @throws Exception if rendering failed
*/
protected void renderReportUsingWriter(net.sf.jasperreports.engine.JRExporter exporter,
JasperPrint populatedReport, HttpServletResponse response) throws Exception {
// Copy the encoding configured for the report into the response.
String contentType = getContentType();
String encoding = (String) exporter.getParameter(net.sf.jasperreports.engine.JRExporterParameter.CHARACTER_ENCODING);
if (encoding != null) {
// Only apply encoding if content type is specified but does not contain charset clause already.
if (contentType != null && !contentType.toLowerCase().contains(WebUtils.CONTENT_TYPE_CHARSET_PREFIX)) {
contentType = contentType + WebUtils.CONTENT_TYPE_CHARSET_PREFIX + encoding;
}
}
response.setContentType(contentType);
// Render report into HttpServletResponse's Writer.
JasperReportsUtils.render(exporter, populatedReport, response.getWriter());
}
/**
* We need to write binary output to the response OutputStream.
* @param exporter the JasperReports exporter to use
* @param populatedReport the populated {@code JasperPrint} to render
* @param response the HTTP response the report should be rendered to
* @throws Exception if rendering failed
*/
protected void renderReportUsingOutputStream(net.sf.jasperreports.engine.JRExporter exporter,
JasperPrint populatedReport, HttpServletResponse response) throws Exception {
// IE workaround: write into byte array first.
ByteArrayOutputStream baos = createTemporaryOutputStream();
JasperReportsUtils.render(exporter, populatedReport, baos);
writeToResponse(response, baos);
}
/**
* Create a JasperReports exporter for a specific output format,
* which will be used to render the report to the HTTP response.
* The {@code useWriter} method determines whether the
* output will be written as text or as binary content.
* @see #useWriter()
*/
protected abstract net.sf.jasperreports.engine.JRExporter createExporter();
/**
* Return whether to use a {@code java.io.Writer} to write text content
* to the HTTP response. Else, a {@code java.io.OutputStream} will be used,
* to write binary content to the response.
* @see javax.servlet.ServletResponse#getWriter()
* @see javax.servlet.ServletResponse#getOutputStream()
*/
protected abstract boolean useWriter();
}