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Follow UsBy: Anadi Misra
Jasper Reports is a popular open source reporting solution written completely in Java.
It can be integrated into any Java or
Java EE project. We know about its ability to create reports in multi-formats
and its ability to integrate with web pages. However, this product is not well
documented. In this article, we look into Jasper Reports and associated tools
and their applicability to various scenarios.
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How it works
Jasper Reports uses XML to define its
report files. The format used is rather conventional and the definition files
are saved with a JRXML extension. This definition file contains all the
information about the report such as title, headers and footers, and of course,
the report details. All this information is characterized and defined within
respective tags.
After the report has been defined, it needs to be compiled into
a binary format to view the report in an existing Java application. You can even
integrate it with web pages such as those from JSP or even JSF pages. To use it,
you simply need to download the package from http://jasperreports.
sourceforge.net and make sure you have the JARs in the DIST folder of the Jasper
Reports package folder and the path included in the CLASSPATH variable.
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| The Jasper Assistant plugin for Eclipse allows visual configuration of data source and designs the report from the 'Jasper Assistant Perspective' |
Sample report
The first step in using Jasper
Reports is to write the report definition file. You can use any text or WYSIWYG
editor. We will design a simple report that displays 'Hello World' in a PDF
document. The report definition invariably includes the following
definitions.
For the sake of simplicity, we have omitted the tags that define the header and footer respectively.
All the report data is displayed under the
formatting information (such as headers and title) has been defined. The content
of report is defined under the detail tag. The
displays static text in the report. The
of the elements contain a 'band' element as its only child element.
Next, we
need to compile this into a binary file. This can be achieved by calling the
compileReport() method on the 'net.sf.jasperreports.engine.
JasperCompileManager' class. Of many methods available, in this example, we will
use the one that takes a single String parameter. The following code handles
report display in the Java class.
// import the library
import net.sf.jasperreports.engine.*;
...
JasperReport jasRep;
JasperPrint jasPrnt;
Try {
     jasRep =
JasperCompileManager.compileReport(
        Â
"reports/demo.jrxml");
     jasPrnt =
JasperFillManager.fillReport(
         jasRep, new HashMap(),
new JREmptyDataSource());
    Â
JasperExportManager.exportReportToPdfFile(
         jasPrnt,
"reports/demo.pdf");
} catch (JRException exp) {
     exp.printStackTrace();
}
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| Use any text editor to write the XML file that creates the report. Jasper then pulls required data from a data source and saves it |
The first statement compiles the report into a binary format.
The binary skeletal framework of the report then needs some data, (static “Hello
World!” text in our case) which is provided by the fillReport() method in the
code.
Lastly, we have exported the report to a PDF file using the
exportReportToPdfFile() as seen in the preceding code snippet. For this example
to compile and run, you need the following string in your CLASSPATH:
jasperreports-1.2.1.jar; commons-beanutils-1.5.jar; commons-collections-2.1.jar;
commons-digester- 1.7.jar; commons-logging-1.0.2.jar; commons-logging-api-1.0.2.
jar; itext-1.3.1.jar.
The version numbers can be different depending on the version
of jasper reports being used. Also note that you need to import
'poi-2.0-final-20040126.jar' instead of 'itext-1.3.x.jar' if you intend to
export to an Excel file.
Jasper tools
The above example was a demonstration
of Jasper
made it to do. For more advanced scenarios, you can use the GUI based Jasper
Assistant, which helps you visually build the report, saving your time and
effort. Jasper Assistant can be downloaded from
The assistant is based on Eclipse's plug-in architecture. So
all you need to do is download the package and extract it to the Eclipse
installation folder and start IDE. However, you need also plug-ins such as EMF
(Eclipse Modeling Framework) SDK and GEF (Graphical Editing Framework) SDK
installed in your Eclipse IDE before you can use the Jasper Assistant. The
plug-ins are available at Eclipse's website for free.
Once all the plug-ins are installed, you can simply add a
report to your application. First, create a data source for your report through
the Data Sources section available in 'Window>Preferences>Jasper
Assistant'. Switch to new perspective from Window>Open
Perspective>Other>Jasper Assistant and then choose the File>
New>Report menu to create new Report.
The New Report Wizard then guides you through the initial
steps of report creation, where it connects to the database over a data source
and lets you specify the query or select the fields that will be displayed in
the report. To design the report, you can drag the fields you need to show into
the design editor. Also, you can add bands such as title, page header and column
headers and also format them from the 'Properties' window in the Jasper
Assistant Perspective.
Tweaking app servers for Jasper reports
Jasper
Reports can also be displayed from Web pages.
make following changes in your app server for that. For Sun's application
server, add the below line in the D:\Sun\
AppServer\domains\domain1\config\server.policy file, assuming that 'domain1' is
the currently used domain in the application server.
grant{ permission
java.lang.RuntimePermission "createClassLoader"};
Similarly, for Tomcat, add the following line to the startup
script (startup.bat for Windows and startup.sh for Linux):
CATALINA_OPTS="$CATALINA_OPTS
-Djava.awt.headless=true"
So, whenever you have to make complex reports, you know which
way you have to head.
Source: PCQuest