Apache FOP and XSL to generate PDF

Generate PDF using Apache FOP and XSL

This blog will demonstrate to generate PDF using XSL and Apache FOP.

In this smaple code below, the XML to print the required info is set in the String variable. This can be impovised to fetch the data from different data source (database), and logically construct the XML to create the PDF.
- The XML content can added in a file and, we can provide that as input .

Sample XML content

<Report>
<Title>.. </Title>
<For>..</For>
<Employees>
  <Employee>
    <Name>...</Name>
    <Department>..</Department>
  </Employee>
</Employees>
</Report>

XSL template

XSL template definition file:
- This file is generated using the IDE itself, not tools used.
- Along with the XSL stylesheet tags, we also use fop namespace tags.
- The values of the XML is fetched using the XPATH format
  - Save below xml content in a file (employee-pdf.xsl) under resources/ directory.
  - Make sure the folder is part of the classpath.

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:fo="http://www.w3.org/1999/XSL/Format">


    <xsl:variable name="topic" select="/Report/Title" />
    <xsl:output method="xml" />

    <xsl:template match="/">
        <fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">
            <fo:layout-master-set>
                <fo:simple-page-master margin-right="2.0cm"
                    margin-left="2.0cm" margin-bottom="2.0cm" margin-top="2.0cm"
                    page-height="29.7cm" page-width="21cm" master-name="test">
                    <fo:region-body margin-top="2.5cm" margin-bottom="1.0cm" />
                    <fo:region-before extent="5cm" />
                    <fo:region-after extent="1cm" />
                </fo:simple-page-master>
            </fo:layout-master-set>
            <!-- master-name should match the master-name in the simple-page-master -->
            <fo:page-sequence master-reference="test">
                <xsl:text>&#10;</xsl:text>

                <fo:static-content flow-name="xsl-region-before">
                    <xsl:text>&#10;</xsl:text>
                    <!-- <fo:table><xsl:text>&#10;</xsl:text> -->
                    <fo:table table-layout="fixed" width="100%" border-collapse="separate">
                        <fo:table-column column-width="7.5cm" /><xsl:text>&#10;</xsl:text>
                        <fo:table-column column-width="8.5cm" /><xsl:text>&#10;</xsl:text>
                        <fo:table-body><xsl:text>&#10;</xsl:text>
                            <fo:table-row><xsl:text>&#10;</xsl:text>
                                <fo:table-cell border="0.5pt solid white"> <!-- No border is needed so white -->
                                    <fo:block line-height="15pt" font-size="10pt"
                                        font-weight="bold" text-align="center" space-after="5mm">
                                        <xsl:text>Report Name: </xsl:text><xsl:value-of select="/Report/Title" />
                                    </fo:block><xsl:text>&#10;</xsl:text>
                                </fo:table-cell><xsl:text>&#10;</xsl:text>
                                <fo:table-cell border="0.5pt solid white"> <!-- No border is needed so white -->
                                    <fo:block line-height="15pt" font-size="10pt"
                                        font-weight="bold" text-align="center" space-after="5mm">
                                        <xsl:text>Used For: </xsl:text><xsl:value-of select="/Report/For" />
                                    </fo:block><xsl:text>&#10;</xsl:text>
                                </fo:table-cell><xsl:text>&#10;</xsl:text>
                            </fo:table-row>
                        </fo:table-body>
                    </fo:table>
                </fo:static-content>
                <!-- Flow name is required part of the validation -->
                <fo:flow flow-name="xsl-region-body">
                    <fo:table table-layout="fixed" width="100%" border-collapse="separate">
                        <fo:table-column column-width="7.5cm" /><xsl:text>&#10;</xsl:text>
                        <fo:table-column column-width="7.5cm" /><xsl:text>&#10;</xsl:text>
                        <!-- <xsl:call-template name=""></xsl:call-template> -->
                        <fo:table-body><xsl:text>&#10;</xsl:text>
                            <fo:table-row><xsl:text>&#10;</xsl:text>
                                <fo:table-cell border="0.5pt solid black" height="15pt">
                                    <fo:block line-height="10pt" font-size="10pt"
                                        font-weight="bold" text-align="center" vertical-align="middle"
                                        space-after="5mm" space-before="5mm">
                                        <xsl:text>Employee Name</xsl:text>
                                    </fo:block><xsl:text>&#10;</xsl:text>
                                </fo:table-cell><xsl:text>&#10;</xsl:text>
                                <fo:table-cell border="0.5pt solid black" height="15pt">
                                    <fo:block line-height="10pt" font-size="10pt"
                                        font-weight="bold" text-align="center" vertical-align="middle"
                                        space-after="5mm" space-before="5mm">

                                        <xsl:text> Department </xsl:text>
                                    </fo:block><xsl:text>&#10;</xsl:text>
                                </fo:table-cell><xsl:text>&#10;</xsl:text>
                            </fo:table-row>
                            <xsl:apply-templates select="Report/Employees" />
                        </fo:table-body>
                    </fo:table>
                </fo:flow>
            </fo:page-sequence>
        </fo:root>
    </xsl:template>
    <xsl:template match="/Report/Employees">
        <xsl:for-each select="./Employee">
            <fo:table-row>
                <fo:table-cell border="0.5pt solid black">
                    <fo:block font-size="8pt" text-align="center" vertical-align="middle">
                        <xsl:value-of select="Name" />
                    </fo:block>
                </fo:table-cell>
                <fo:table-cell border="0.5pt solid black">
                    <fo:block font-size="8pt" text-align="center" vertical-align="middle">
                        <xsl:value-of select="Department" />
                    </fo:block>
                </fo:table-cell>
            </fo:table-row>
        </xsl:for-each>
    </xsl:template>
</xsl:stylesheet>

Java code entry point

Java main code to generate the PDF
- Two apporach is defined
  - 1. Without the FOPUserAgent
  - 1. With the FOPUserAgent

package xsltdemo.xsltdemo;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.StringReader;

import javax.xml.transform.Result;
import javax.xml.transform.Templates;
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.fop.apps.FOUserAgent;
import org.apache.fop.apps.Fop;
import org.apache.fop.apps.FopFactory;
import org.apache.xalan.xsltc.trax.TransformerFactoryImpl;
import org.xml.sax.SAXException;

public class App {

    public static void main(String[] args) {
        System.out.println("Process Started");
        createPDF();
        createPDFPerDoc();
        System.out.println("Process Completed");
    }

    public static void createPDF() {

        /**************************************************************
         ****  https://xmlgraphics.apache.org/fop/2.7/embedding.html **
         ****  https://xmlgraphics.apache.org/fop/fo.html            **
         **************************************************************/


        //Template file created for XSLT transformation
        //This include fop namespace used for PDF creation
        //In the IDE, i created a src folder resources and kept the file
        String templateXSL ="resources/employee-pdf.xsl";
        //Fetching the content from the variable within the class.
        //we can also read the content from file
        //For reading content from file, we can pass File object in StreamSource 
        // instead of string
        String templateXMLContent = createXml();
        try {

            TransformerFactory transformerFactory = new TransformerFactoryImpl();

            //If we are reading the content from file, use new File("file-path-of-xml");
            //instead of string in StreamSource
            Transformer transformer = transformerFactory.newTransformer(new StreamSource(templateXSL));

            //The output stream for the PDF to be generated
            OutputStream out = new FileOutputStream("test-demo.pdf");

            //We can specify the fo config file, in new Instance, so FOP factory can use it
            // In our case we are simply setting the setting current working directory as base for configuration
            FopFactory fopFactory = FopFactory.newInstance(new File(".").toURI());

            //Setting the desired output format
            Fop fop = fopFactory.newFop(org.apache.xmlgraphics.util.MimeConstants.MIME_PDF, out);

            //provide the fop handler for SAX parser to handle fop events
            Result res = new SAXResult(fop.getDefaultHandler());

            //actual XSLT transform using FOP happens here
            transformer.transform(new StreamSource(new StringReader(templateXMLContent)),res);

        } catch (SAXException | IOException | TransformerException e) {
            e.printStackTrace();
        }
    }

    public static String createXml() {

        String str ="";

        str = "<Report>"
                + "<Title>Employee Details</Title>"
                + "<For>Department Info</For>"
                +"<Employees>"
                +"<Employee>"
                +"<Name>Ram</Name>"
                +"<Department>Finance</Department>"
                + "</Employee>"
                +"<Employee>"
                +"<Name>Tim</Name>"
                +"<Department>Sale</Department>"
                + "</Employee>"
                + "</Employees>"
                + "</Report>";
        return str;
    }
    /*
      Uses FOPUserAgent
    */
    public static void createPDFPerDoc() {
        OutputStream out;
         FopFactory fopFactory = FopFactory.newInstance(new File(".").toURI());
        TransformerFactory tFactory = TransformerFactory.newInstance();
        try {
            String templateXSL ="resources/employee-pdf.xsl";
            //Load the stylesheet
            Templates templates = tFactory.newTemplates(
                new StreamSource(new File(templateXSL)));

            //First run (to /dev/null)
            out = new org.apache.commons.io.output.NullOutputStream();
            FOUserAgent foUserAgent = fopFactory.newFOUserAgent();
            Fop fop = fopFactory.newFop(org.apache.xmlgraphics.util.MimeConstants.MIME_PDF, foUserAgent, out);
            Transformer transformer = templates.newTransformer();
            transformer.setParameter("page-count", "#");
            transformer.transform(new StreamSource(new StringReader(createXml())),
                new SAXResult(fop.getDefaultHandler()));

            //Get total page count
            //String pageCount = Integer.toString(Driver.getResults().getPageCount());
            String pageCount ="2"; 

            //Second run (the real thing)
            out = new java.io.FileOutputStream("test-demo-2.pdf");
            out = new java.io.BufferedOutputStream(out);
            try {
              foUserAgent = fopFactory.newFOUserAgent();
              fop = fopFactory.newFop(org.apache.xmlgraphics.util.MimeConstants.MIME_PDF, foUserAgent, out);
              transformer = templates.newTransformer();
              transformer.setParameter("page-count", pageCount);
              transformer.transform(new StreamSource(new StringReader(createXml())),
                  new SAXResult(fop.getDefaultHandler()));
            } finally {
                out.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Jar dependencies

Dependencies for the code pom.xml
- Note: I excluded xml-apis, since the javaxml.sax pacakge in java 11 displayed a module conflict.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>xsltdemo</groupId>
    <artifactId>xsltdemo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>xsltdemo</name>
    <url>http://www.example.com</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>11</java.version>
        <maven.compiler.source>${java.version}</maven.compiler.source>
        <maven.compiler.target>${java.version}</maven.compiler.target>
        <maven.compiler.release>${java.version}</maven.compiler.release>

        <junit>5.6.2</junit>

        <!-- Plugin versions -->
        <maven.shade>3.2.2</maven.shade>
        <maven.clean>3.1.0</maven.clean>
        <maven.resources>3.1.0</maven.resources>
        <maven.compiler>3.8.1</maven.compiler>
        <maven.surefire>3.0.0-M5</maven.surefire>
        <maven.jar>3.2.0</maven.jar>
        <maven.install>3.0.0-M1</maven.install>
    </properties>

    <dependencies>
        <!-- Dependencies -->
        <dependency>
            <groupId>org.apache.xmlgraphics</groupId>
            <artifactId>fop</artifactId>
            <version>2.7</version>
            <exclusions>
              <!-- Exclucsion done for fixing javaxml.sax issue module conflict issue-->
               <exclusion>
                  <groupId>xml-apis</groupId>
                   <artifactId>xml-apis</artifactId>
              </exclusion>
         </exclusions> 
        </dependency>   

        <!-- Testing dependencies-->
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-api</artifactId>
            <version>${junit}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-engine</artifactId>
            <version>${junit}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-params</artifactId>
            <version>${junit}</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <artifactId>maven-clean-plugin</artifactId>
                <version>3.1.0</version>
            </plugin>
            <plugin>
                <artifactId>maven-resources-plugin</artifactId>
                <version>3.1.0</version>
            </plugin>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
            </plugin>
            <plugin>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>3.0.0-M4</version>
            </plugin>
            <plugin>
                <artifactId>maven-jar-plugin</artifactId>
                <version>3.2.0</version>
            </plugin>
            <plugin>
                <artifactId>maven-install-plugin</artifactId>
                <version>3.0.0-M1</version>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>${maven.shade}</version>
                <executions>
                <execution>
                    <phase>package</phase>
                    <goals>
                    <goal>shade</goal>
                    </goals>
                    <configuration>
                    <transformers>
                        <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                        <mainClass>xsltdemo.xsltdemo.App</mainClass>
                        </transformer>
                    </transformers>
                    </configuration>
                </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

Generate PDF report using Apache FOP and XLS

Table of contents

Generate PDF using Apache FOP and XSL

Sample XML content

XSL template

Java code entry point

Jar dependencies

Output