org.springframework.web.servlet.view.jasperreports.AbstractJasperReportsSingleFormatView Maven / Gradle / Ivy
/*
* Copyright 2002-2006 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.HashMap;
import java.util.Iterator;
import java.util.Map;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import net.sf.jasperreports.engine.JRExporter;
import net.sf.jasperreports.engine.JRExporterParameter;
import net.sf.jasperreports.engine.JasperPrint;
import org.springframework.ui.jasperreports.JasperReportsUtils;
import org.springframework.util.CollectionUtils;
import org.springframework.web.util.WebUtils;
/**
* Extends 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: createExporter
* to create a JasperReports exporter for a specific output format, and
* useWriter to determine whether to write text or binary content.
*
* @author Rob Harrop
* @author Juergen Hoeller
* @since 1.1.5
* @see #createExporter()
* @see #useWriter()
*/
public abstract class AbstractJasperReportsSingleFormatView extends AbstractJasperReportsView {
/**
* Initial size for the output array.
*/
private static final int OUTPUT_BYTE_ARRAY_INITIAL_SIZE = 4096;
/**
* Perform rendering for a single Jasper Reports exporter, that is,
* for a pre-defined output format.
*/
protected void renderReport(JasperPrint populatedReport, Map model, HttpServletResponse response)
throws Exception {
// Prepare report for rendering.
JRExporter exporter = createExporter();
// Set exporter parameters - overriding with values from the Model.
Map mergedExporterParameters = mergeExporterParameters(model);
if (!CollectionUtils.isEmpty(mergedExporterParameters)) {
exporter.setParameters(mergedExporterParameters);
}
if (useWriter()) {
// We need to write text to the response Writer.
// Copy the encoding configured for the report into the response.
String contentType = getContentType();
String encoding = (String) exporter.getParameter(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().indexOf(WebUtils.CONTENT_TYPE_CHARSET_PREFIX) == -1) {
contentType = contentType + WebUtils.CONTENT_TYPE_CHARSET_PREFIX + encoding;
}
}
response.setContentType(contentType);
// Render report into HttpServletResponse's Writer.
JasperReportsUtils.render(exporter, populatedReport, response.getWriter());
}
else {
// We need to write binary output to the response OutputStream.
// Apply the content type as specified - we don't need an encoding here.
response.setContentType(getContentType());
// Render report into local OutputStream.
// IE workaround: write into byte array first.
ByteArrayOutputStream baos = new ByteArrayOutputStream(OUTPUT_BYTE_ARRAY_INITIAL_SIZE);
JasperReportsUtils.render(exporter, populatedReport, baos);
// Write content length (determined via byte array).
response.setContentLength(baos.size());
// Flush byte array to servlet output stream.
ServletOutputStream out = response.getOutputStream();
baos.writeTo(out);
out.flush();
}
}
/**
* Merges the configured JRExporterParameters with any specified in the supplied model data.
* JRExporterParameters in the model override those specified in the configuration.
* @see #setExporterParameters(java.util.Map)
*/
protected Map mergeExporterParameters(Map model) {
Map mergedParameters = new HashMap();
Map convertedExporterParameters = getConvertedExporterParameters();
if (!CollectionUtils.isEmpty(convertedExporterParameters)) {
mergedParameters.putAll(convertedExporterParameters);
}
for (Iterator it = model.keySet().iterator(); it.hasNext();) {
Object key = it.next();
if (key instanceof JRExporterParameter) {
Object value = model.get(key);
if (value instanceof String) {
mergedParameters.put(key, value);
}
else {
if (logger.isWarnEnabled()) {
logger.warn("Ignoring exporter parameter [" + key + "]: value is not a String");
}
}
}
}
return mergedParameters;
}
/**
* Create a JasperReports exporter for a specific output format,
* which will be used to render the report to the HTTP response.
*
The useWriter method determines whether the
* output will be written as text or as binary content.
* @see #useWriter()
*/
protected abstract JRExporter createExporter();
/**
* Return whether to use a java.io.Writer to write text content
* to the HTTP response. Else, a 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();
}