Welcome back to Java Reporting series. For those who didn't read the introductory article; have a look herebefore we get started. Today we're going to have a quick tour in JasperReport architecture, development lifecycle, report definition files, and finally we're going to set up our environment and start work in a sample application.

Architecture

As shown in the above figure JasperReports architecture is based on declarative XML fileswhich by convention have an extension of jrxml that contains the report layout. A lot of third-party design tools were produced to generate your jrxml file in a smooth way (like iReport or JasperAssistant)Design file is supposed to be filled by report's result which is fetched from database, XML files, Java collection, Comma-separated values or Models. Jasper can communicate with those data-sources and more, it can merge any number of data-sources together and manipulates the results of any combinations. This communication goes through JDBC, JNDI, XQuery, EJBQL, Hibernate or existing Oracle PL/SQL. You also can define your own data-source class and pass it to jasper engine directly. After defining your report design layout in jrxml format and determining your data source(s) jasper engine does the rest of work. It compiles your design file and fills it with results fetched from data-source and generates your report to the chosen exporting format (PDF, Excel, HTML, XML, RTF, TXT …, etc.)

Report Definition file structure (jrxml):

Jasper design file –jrxml- contains the following elements:

• <jasperReport>: the root element.
• <title>: its contents are printed only once at the beginning of the report
• <pageHeader> - its contents are printed at the beginning of every page in the report.
• <detail> - contains the body of the report, repeated by n number of results
• <pageFooter> - its contents are printed at the bottom of every page in the report.
• <band> - defines a report section, all of the above elements contain a band element as its only child element.

Only the root element is mandatory, the rest of elements are optional.

Environment

• jasperreports-2.0.4.jar
• commons-digester-1.7.jar
• commons-collections-2.1.jar (commons-collections.jar)
• commons-logging-1.0.2.jar
• commons-beanutils.jar
• iText-2.0.7.jar (used infor PDF exporting)

Sample application

We're going to divide the work into two steps:

1. Generate the report design (jrxml file).
2. Implement application that assigns data source, compiles jrxml file and exports result in the chosen format.

Designing The Report

First we create new text file and rename it to sample_report.jrxml, this file should contain the following XML tags.

<!DOCTYPE jasperReport PUBLIC
"//JasperReports//DTD Report Design//EN"
"http://jasperreports.sourceforge.net/dtds/jasperreport.dtd">

<jasperReport name="sample_report" >
<queryString>
<![CDATA[select item_name,item_amount from item
where item_amount <=100]]>
</queryString>
<field name="ITEM_NAME" class="java.lang.String"/>
<field name="ITEM_AMOUNT" class="java.math.BigDecimal"/>
<columnHeader>
<band height="28" isSplitAllowed="true">
<staticText>
<reportElement x="40" y="11" width="193" height="15" key="staticText-1"/>
<text>
<![CDATA[Item Name]]>
</text>
</staticText>
<staticText>
<reportElement x="330" y="11" width="193" height="15" key="staticText-2"/>
<text>
<![CDATA[Item Amount]]>
</text>
</staticText>
</band>
</columnHeader>

<detail>
<band height="27" isSplitAllowed="true">
<textField>
<reportElement x="47" y="6" width="173"
height="18" key="textField"/>
<textFieldExpression class="java.lang.String">
<![CDATA[$F{ITEM_NAME}]]>
</textFieldExpression>
</textField>
<textField >
<reportElement x="330" y="6" width="100"
height="18" key="textField"/>
<textFieldExpression class="java.math.BigDecimal">
<![CDATA[$F{ITEM_AMOUNT}]]>
</textFieldExpression>
</textField>
</band>
</detail>
</jasperReport>

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.HashMap;

import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.JRExporterParameter;
import net.sf.jasperreports.engine.JasperCompileManager;
import net.sf.jasperreports.engine.JasperExportManager;
import net.sf.jasperreports.engine.JasperFillManager;
import net.sf.jasperreports.engine.JasperPrint;
import net.sf.jasperreports.engine.JasperReport;
import net.sf.jasperreports.engine.export.JRXlsExporter;

public static Connection establishConnection()
{
Connection connection = null;
try
{
Class.forName("oracle.jdbc.driver.OracleDriver");
String oracleURL = "jdbc:oracle:thin:@localhost:1521:mySID";
connection = DriverManager.getConnection(oracleURL,"username","password");
connection.setAutoCommit(false);
}
catch(SQLException exception)
{
exception.printStackTrace();
}
return connection;

}

/* JasperReport is the object
that holds our compiled jrxml file */
JasperReport jasperReport;


/* JasperPrint is the object contains
report after result filling process */
JasperPrint jasperPrint;

// connection is the data source we used to fetch the data from
Connection connection = establishConnection(); 
// jasperParameter is a Hashmap contains the parameters
// passed from application to the jrxml layout
HashMap jasperParameter = new HashMap();

// jrxml compiling process
jasperReport = JasperCompileManager.compileReport
("C://sample_report.jrxml");

// filling report with data from data source

jasperPrint = JasperFillManager.fillReport(jasperReport,jasperParameter, connection); 

// exporting process
// 1- export to PDF
JasperExportManager.exportReportToPdfFile(jasperPrint, "C://sample_report.pdf");

// 2- export to HTML
JasperExportManager.exportReportToHtmlFile(jasperPrint, "C://sample_report.html" ); 

// 3- export to Excel sheet
JRXlsExporter exporter = new JRXlsExporter();
exporter.setParameter(JRExporterParameter.JASPER_PRINT, jasperPrint);
exporter.setParameter(JRExporterParameter.OUTPUT_FILE_NAME, "C://simple_report.xls" );

exporter.exportReport();

You have just managed to generate your first jasper report in 3 different file formats at C:\\ directory (shown in the image below):

- sample_report.html
- sample_report.pdf
- sample_report.xls

Here we reach the end of today's article, next article we will cover the following points:
1- Using design tool (iReport) to generate robust and smooth jrxml file.
2- Create run-time search criteria and pass them to report.

Note: this Article was first published in FCI-H Blog, here