https://github.com/spring-projects/spring-framework: Spring Web MVC (Spring IO)
  • Juergen Hoeller 
/*
 * Copyright 2002-2018 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.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.PdfStamper;

import org.springframework.util.Assert;
import org.springframework.web.servlet.view.AbstractUrlBasedView;


Abstract superclass for PDF views that operate on an existing
document with an AcroForm. Application-specific view classes
will extend this class to merge the PDF form with model data.

This view implementation uses Bruno Lowagie's
iText API.
Known to work with the original iText 2.1.7 as well as its fork
OpenPDF.
We strongly recommend OpenPDF since it is actively maintained
and fixes an important vulnerability for untrusted PDF content.

Thanks to Bryant Larsen for the suggestion and the original prototype!

Author:Juergen Hoeller
See Also:
Since:2.5.4
/**
 * Abstract superclass for PDF views that operate on an existing
 * document with an AcroForm. Application-specific view classes
 * will extend this class to merge the PDF form with model data.
 *
 * <p>This view implementation uses Bruno Lowagie's
 * <a href="http://www.lowagie.com/iText">iText</a> API.
 * Known to work with the original iText 2.1.7 as well as its fork
 * <a href="https://github.com/LibrePDF/OpenPDF">OpenPDF</a>.
 * <b>We strongly recommend OpenPDF since it is actively maintained
 * and fixes an important vulnerability for untrusted PDF content.</b>
 *
 * <p>Thanks to Bryant Larsen for the suggestion and the original prototype!
 *
 * @author Juergen Hoeller
 * @since 2.5.4
 * @see AbstractPdfView
 */
public abstract class AbstractPdfStamperView extends AbstractUrlBasedView {

	public AbstractPdfStamperView(){
		setContentType("application/pdf");
	}


	@Override
	protected boolean generatesDownloadContent() {
		return true;
	}

	@Override
	protected final void renderMergedOutputModel(
			Map<String, Object> model, HttpServletRequest request, HttpServletResponse response) throws Exception {

		// IE workaround: write into byte array first.
		ByteArrayOutputStream baos = createTemporaryOutputStream();

		PdfReader reader = readPdfResource();
		PdfStamper stamper = new PdfStamper(reader, baos);
		mergePdfDocument(model, stamper, request, response);
		stamper.close();

		// Flush to HTTP response.
		writeToResponse(response, baos);
	}

	
Read the raw PDF resource into an iText PdfReader.

The default implementation resolve the specified "url" property
as ApplicationContext resource.

Throws:
See Also:
Returns:the PdfReader instance
/**
	 * Read the raw PDF resource into an iText PdfReader.
	 * <p>The default implementation resolve the specified "url" property
	 * as ApplicationContext resource.
	 * @return the PdfReader instance
	 * @throws IOException if resource access failed
	 * @see #setUrl
	 */
	protected PdfReader readPdfResource() throws IOException {
		String url = getUrl();
		Assert.state(url != null, "'url' not set");
		return new PdfReader(obtainApplicationContext().getResource(url).getInputStream());
	}

	
Subclasses must implement this method to merge the PDF form
with the given model data.

This is where you are able to set values on the AcroForm.
An example of what can be done at this level is:

// get the form from the document
AcroFields form = stamper.getAcroFields();
// set some values on the form
form.setField("field1", "value1");
form.setField("field2", "Vvlue2");
// set the disposition and filename
response.setHeader("Content-disposition", "attachment; FILENAME=someName.pdf");


Note that the passed-in HTTP response is just supposed to be used
for setting cookies or other HTTP headers. The built PDF document itself
will automatically get written to the response after this method returns.

Params:
  • model – the model Map
  • stamper – the PdfStamper instance that will contain the AcroFields.
You may also customize this PdfStamper instance according to your needs,
e.g. setting the "formFlattening" property.
  • request – in case we need locale etc. Shouldn't look at attributes.
  • response – in case we need to set cookies. Shouldn't write to it.
Throws:
  • Exception – any exception that occurred during document building
/**
	 * Subclasses must implement this method to merge the PDF form
	 * with the given model data.
	 * <p>This is where you are able to set values on the AcroForm.
	 * An example of what can be done at this level is:
	 * <pre class="code">
	 * // get the form from the document
	 * AcroFields form = stamper.getAcroFields();
	 *
	 * // set some values on the form
	 * form.setField("field1", "value1");
	 * form.setField("field2", "Vvlue2");
	 *
	 * // set the disposition and filename
	 * response.setHeader("Content-disposition", "attachment; FILENAME=someName.pdf");</pre>
	 * <p>Note that the passed-in HTTP response is just supposed to be used
	 * for setting cookies or other HTTP headers. The built PDF document itself
	 * will automatically get written to the response after this method returns.
	 * @param model the model Map
	 * @param stamper the PdfStamper instance that will contain the AcroFields.
	 * You may also customize this PdfStamper instance according to your needs,
	 * e.g. setting the "formFlattening" property.
	 * @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 any exception that occurred during document building
     */
	protected abstract void mergePdfDocument(Map<String, Object> model, PdfStamper stamper,
			HttpServletRequest request, HttpServletResponse response) throws Exception;

}