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Apache FOP 0.92 servlet driver problem

Posted on 2006-06-27
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Last Modified: 2013-11-24
I'm trying to get Apache Fop 0.92 to work in a servlet. I have it working for FOP 0.20.5, but using the same code in 0.92 gives one problem:

import org.apache.fop.apps.Driver;  

The driver class is no longer part of Fop, and I can't find any info what to do with it. Below is the complete code of the servlet.

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.sax.SAXResult;
import javax.xml.transform.stream.StreamSource;

import org.apache.commons.logging.impl.SimpleLog;
// import org.apache.commons.logging.Log;

//FOP
import org.apache.fop.apps.Driver;  
import org.apache.fop.apps.FOPException;

/**
 * Example servlet to generate a PDF from a servlet.
 * <br/>
 * Servlet param is:
 * <ul>
 *   <li>fo: the path to a XSL-FO file to render
 * </ul>
 * or
 * <ul>
 *   <li>xml: the path to an XML file to render</li>
 *   <li>xslt: the path to an XSLT file that can transform the above XML to XSL-FO</li>
 * </ul>
 * <br/>
 * Example URL: http://servername/fop/servlet/FopServlet?fo=readme.fo
 * <br/>
 * Example URL: http://servername/fop/servlet/FopServlet?xml=data.xml&xslt=format.xsl
 * <br/>
 * For this to work with Internet Explorer, you might need to append "&ext=.pdf"
 * to the URL.
 *
 * @author <a href="mailto:fop-dev@xml.apache.org">Apache XML FOP Development Team</a>
 * @version $Id: FopServlet.java,v 1.2 2003/03/07 09:48:05 jeremias Exp $
 * (todo) Ev. add caching mechanism for Templates objects
 */
public class FopServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;
      /** Name of the parameter used for the XSL-FO file */
    protected static final String FO_REQUEST_PARAM = "fo";
    /** Name of the parameter used for the XML file */
    protected static final String XML_REQUEST_PARAM = "xml";
    /** Name of the parameter used for the XSLT file */
    protected static final String XSLT_REQUEST_PARAM = "xslt";

    /** Logger to give to FOP */
    protected SimpleLog log = null;
    /** The TransformerFactory to use to create Transformer instances */
    protected TransformerFactory transFactory = null;

    /**
     * @see javax.servlet.GenericServlet#init()
     */
    public void init() throws ServletException {
        this.log = new SimpleLog("FOP/Servlet");
        log.setLevel(SimpleLog.LOG_LEVEL_WARN);
        this.transFactory = TransformerFactory.newInstance();
    }

    /**
     * @see javax.servlet.http.HttpServlet#doGet(HttpServletRequest, HttpServletResponse)
     */
    public void doGet(HttpServletRequest request,
                      HttpServletResponse response) throws ServletException {
        try {
            //Get parameters
            String foParam = request.getParameter(FO_REQUEST_PARAM);
            String xmlParam = request.getParameter(XML_REQUEST_PARAM);
            String xsltParam = request.getParameter(XSLT_REQUEST_PARAM);

            //Analyze parameters and decide with method to use
            byte[] content = null;
            if (foParam != null) {
                content = renderFO(foParam);
            } else if ((xmlParam != null) && (xsltParam != null)) {
                content = renderXML(xmlParam, xsltParam);
            } else {
                PrintWriter out = response.getWriter();
                out.println("<html><head><title>Error</title></head>\n"
                          + "<body><h1>FopServlet Error</h1><h3>No 'fo' "
                          + "request param given.</body></html>");
            }

            if (content != null) {
                //Send the result back to the client
                response.setContentType("application/pdf");
                response.setContentLength(content.length);
                response.getOutputStream().write(content);
                response.getOutputStream().flush();
            }

        } catch (Exception ex) {
            throw new ServletException(ex);
        }
    }

    /**
     * Converts a String parameter to a JAXP Source object.
     * @param param a String parameter
     * @return Source the generated Source object
     */
    protected Source convertString2Source(String param) {
        return new StreamSource(new File(param));
    }

    /**
     * Renders an XSL-FO file into a PDF file. The PDF is written to a byte
     * array that is returned as the method's result.
     * @param fo the XSL-FO file
     * @return byte[] the rendered PDF file
     * @throws FOPException If an error occurs during the rendering of the
     * XSL-FO
     * @throws TransformerException If an error occurs while parsing the input
     * file
     */
    protected byte[] renderFO(String fo)
                throws FOPException, TransformerException {

        //Setup source
        Source foSrc = convertString2Source(fo);

        //Setup the identity transformation
        Transformer transformer = this.transFactory.newTransformer();

        //Start transformation and rendering process
        return render(foSrc, transformer);
    }

    /**
     * Renders an XML file into a PDF file by applying a stylesheet
     * that converts the XML to XSL-FO. The PDF is written to a byte array
     * that is returned as the method's result.
     * @param xml the XML file
     * @param xslt the XSLT file
     * @return byte[] the rendered PDF file
     * @throws FOPException If an error occurs during the rendering of the
     * XSL-FO
     * @throws TransformerException If an error occurs during XSL
     * transformation
     */
    protected byte[] renderXML(String xml, String xslt)
                throws FOPException, TransformerException {

        //Setup sources
        Source xmlSrc = convertString2Source(xml);
        Source xsltSrc = convertString2Source(xslt);

        //Setup the XSL transformation
        Transformer transformer = this.transFactory.newTransformer(xsltSrc);

        //Start transformation and rendering process
        return render(xmlSrc, transformer);
    }

    /**
     * Renders an input file (XML or XSL-FO) into a PDF file. It uses the JAXP
     * transformer given to optionally transform the input document to XSL-FO.
     * The transformer may be an identity transformer in which case the input
     * must already be XSL-FO. The PDF is written to a byte array that is
     * returned as the method's result.
     * @param src Input XML or XSL-FO
     * @param transformer Transformer to use for optional transformation
     * @return byte[] the rendered PDF file
     * @throws FOPException If an error occurs during the rendering of the
     * XSL-FO
     * @throws TransformerException If an error occurs during XSL
     * transformation
     */
    protected byte[] render(Source src, Transformer transformer)
                throws FOPException, TransformerException {

        //Setup FOP
        Driver driver = new Driver();
        driver.setRenderer(Driver.RENDER_PDF);
        // driver.initialize();
       
        //Setup output
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        driver.setOutputStream(out);

        //Make sure the XSL transformation's result is piped through to FOP
        Result res = new SAXResult(driver.getContentHandler());

        //Start the transformation and rendering process
        transformer.transform(src, res);

        //Return the result
        return out.toByteArray();
    }

}
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Question by:grexx
2 Comments
 
LVL 35

Accepted Solution

by:
girionis earned 250 total points
ID: 16999284
> The driver class is no longer part of Fop, and I can't find any info what to do with it. Below is the complete code of the servlet.

Find the jar file it is in and simply put it in your classpath. This should work.
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