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This article by David Heffelfinger teaches you how to add reporting capabilities to our Java applications. This can be easily done by taking advantage of the classes included in the JasperReports class library. JasperReports can be easily embedded into both client and server-side Java applications simply by adding the required libraries to our CLASSPATH and calling the appropriate methods in the JasperReports API.
At the end of this article, we will be able to:
- Identify the purpose of the several downloads that can be found at the JasperReports web site
- Set up our development and execution environment to successfully add reporting capabilities to our Java applications
- Identify the required libraries for adding reporting capabilities to Java applications
- Identify the optional libraries that can be used to enhance the reporting capabilities of our Java applications
JasperReports is distributed as a JAR file that needs to be added to the CLASSPATH of any application we wish to add reporting capabilities to. JasperReports can be downloaded from http://jasperforge.org/plugins/project/project_home.php?group_id=102.
Clicking on the Download link around the center of the page will take us to the JasperReports download page on SourceForge.net.
The specific version on your screen might be different; at the time of writing, the latest stable version of JasperReports is 3.5.2.
It is not always clear what exactly is downloaded by clicking on these links; thus, we will provide a brief explanation of what each link is for.
- jasperreports-3.5.2-applet.jar: This first download link is for a JAR file containing a subset of the JasperReports functionality. Specifically, it contains classes that can be used to display JasperPrint files, which are reports in JasperReports' native format. This file is offered as a separate download as a convenience for developers; it can be used for applications or applets that don't need full reporting capabilities, yet need to display generated reports. Even though the filename has a suffix of "applet", there is nothing preventing us from using it with standalone applications, without the overhead that the missing JasperReports classes would add to the download. This file is approximately 346 KB in size.
- jasperreports-3.5.2.jar: This is the second download link, and it is the complete JasperReports class library. It contains all classes necessary to compile, fill, and export reports, but does not include any additional libraries that JasperReports depends on. This is the minimum file requirement for us to add full reporting capabilities to our Java applications. However, if we choose to download this file, we need to download the JasperReports dependencies separately. This file is approximately 2.2 MB in size.
- jasperreports-3.5.2-javaflow.jar: This is the third download link, and it is the javaflow version of JasperReports. This version of JasperReports should be used in environments where multithreading is discouraged. This file is approximately 2.2 MB in size.
- jasperreports-3.5.2-project.tar.gz: This is the fourth download link, and it contains the complete JasperReports class library plus all the required and optional libraries. In addition, it contains the entire file as a gzipped TAR file, which is common in Unix and Unix-like systems, such as Linux. This download also includes the JasperReports source code and a lot of source code providing examples of JasperReports' functionality. This gzipped TAR file is approximately 42 MB in size
- jasperreports-3.5.2-project.zip: The fifth download link, like the fourth link, contains the complete JasperReports class library plus all the required and optional libraries, along with the JasperReports source code. However, it contains the files in ZIP format, which is more commonly used under Microsoft Windows. This file is approximately 51 MB in size.
Unless Internet connection speed is an issue, we recommend downloading one of the last two mentioned files, as they include everything we need to create reports with JasperReports. Another good reason to download one of these files is that the included examples are a great way to learn how to implement the different JasperReports features. All of the examples in the file come with an ANT build file containing targets to compile and execute them.
We will refer to this file as the JasperReports project file, or more succinctly, as the project file.
Once we have downloaded the appropriate file for our purposes, we need to set up our environment to be able to start creating reports. In the next section, we discuss how to do this, assuming that the project file was downloaded.
Setting up our environment
To set up our environment to get ready for creating reports, we need to extract the JasperReports project ZIP file to a location of our choice. Once we extract the project ZIP file, we should see a jasperreports-3.5.2 directory (The actual name of the directory may vary slightly depending on the version of JasperReports.) containing the following files and directories:
- build: This directory contains the compiled JasperReports class files.
- build.xml: This is an ANT build file, which builds the JasperReports source code. If we don't intend to modify JasperReports, we don't need to use this file as JasperReports is distributed in compiled form.
- changes.txt: This file explains the differences between the current and previous versions of the JasperReports' class library.
- demo: This directory contains various examples demonstrating several aspects of JasperReports functionality.
- dist: This directory contains a JAR file containing the standard, javaflow, and applet versions of the JasperReports library. We should add one of these JAR files to our CLASSPATH to take advantage of JasperReports functionality.
- docs: This directory contains a quick reference guide to most XML tags used in JasperReports templates.
- lib: This directory contains all the libraries needed to build JasperReports and to use it in our applications.
- license.txt: This file contains the full text of the LGPL license.
- pom.xml: This is a Maven 2 POM file used to build JasperReports with Maven, just like build.xml. We don't need this file because JasperReports is distributed in compiled form.
- readme.txt: This file contains instructions on how to build and execute the supplied examples.
- src: This directory contains the JasperReports source code.
Getting up and running quickly
To get up and run quickly, the files to add to the CLASSPATH are the JasperReports JAR files, and all the JAR files under the lib directory in the project ZIP file. By adding these files to the CLASSPATH, we don't have to worry about the CLASSPATH when implementing additional functionality, for example, when exporting to PDF or producing charts.
JasperReports class library
For all JasperReports-related tasks, we need to add the JasperReports library to our CLASSPATH. The JasperReports library can be found under the dist directory in the project file; it is named jasperreports-3.5.2.jar. Depending on the version of JasperReports, the filename will vary.
Required libraries for report compilation
The project file described earlier contains all of the required supporting libraries. Once that file is downloaded, all the required libraries can be found under the lib subdirectory of the directory created when extracting the ZIP file. JasperReports uses these required files for XML parsing. Therefore, they are needed when compiling JRXML files programmatically, not for filling or displaying reports. JRXML files can be compiled using a custom ANT task provided by JasperReports. If we choose to compile our JRXML files using this custom ANT target, these required libraries need to be added to the CLASSPATH variable of the ANT build file. There are example build files included in the project file and also at http://www.packtpub.com/files/code/8082_Code.zip.
The following discussion about libraries highlights the fact that JasperReports makes extensive use of Apache Commons.
Apache Commons Digester
The Commons Digester library includes utility classes used to initialize Java objects from XML files. JasperReports takes advantage of the Digester component of the Apache Commons repository to implement its XML parsing functionality. Version 3.5.2 of the JasperReports project ZIP file includes version 1.7 of Commons Digester. The filename is commons-digester-1.7.jar, and it must be on your CLASSPATH for your JasperReports application to work correctly.
If you downloaded the bare JasperReports class library, you will need to download Commons Digester separately from http://commons.apache.org/digester/.
Apache Commons Collections
Another component of the Apache Commons suite is the Collections component. This component provides functionality to complement and augment the Java Collections framework. JasperReports takes advantage of the Collections component of Apache Commons to implement some of its functionality. Like all required libraries included in the project ZIP file, the Commons Collections library can be found under the lib subdirectory of the directory created when extracting the project ZIP file. JasperReports project file version 3.5.2 includes version 2.1 of Commons Collections, distributed as a JAR file named commons-collections-2.1.jar.
If you have downloaded the bare JasperReports class library, you will need to download Commons Collections separately from http://commons.apache.org/collections/.
Apache Commons Logging
Apache Commons Logging is a component of the Apache Commons that provides components to aid developers with sending data to log files. JasperReports takes advantage of this component, which can be found on the lib directory of the project ZIP file. The version included with JasperReports 3.5.2 is Commons Logging 1.0.2. The file to be added to your CLASSPATH is commons-logging-1.0.2.jar.
If you have downloaded the bare JasperReports class library, you will need to download Commons Logging separately from http://commons.apache.org/logging/.
Apache Commons BeanUtils
The last library that JasperReports requires for compiling reports is Apache Commons BeanUtils. BeanUtils is a library that provides easy-to-use wrappers around the Java reflection and introspection APIs. Version 3.5.2 of the JasperReports project ZIP file includes BeanUtils 1.8; the file to add to your CLASSPATH is commons-beanutils-1.8.jar.
If you have downloaded the bare JasperReports class library, you will need to download Commons BeanUtils separately from http://commons.apache.org/beanutils/.
Optional libraries and tools
There are a number of libraries that are required only if we wish to take advantage of some of JasperReports' features. These optional libraries and their uses are listed next.
JasperReports comes bundled with some custom ANT targets for previewing report designs and for viewing reports serialized in JasperReports' native format. Although not strictly necessary, it is very helpful to have ANT available to take advantage of these custom targets.
ANT can be downloaded from http://ant.apache.org/.
JDT (Java Development Tools) compiler is the Java compiler included with the Eclipse IDE. The JDT compiler is needed only if the JasperReports application is running under a Java Runtime Environment (JRE) and not under a full JDK.
When creating reports, JasperReports creates temporary Java files and compiles them. When using a JDK, JasperReports takes advantage of tools.jar for this functionality. As a JRE does not include tools.jar, the JDT compiler is needed. The JasperReports project file version 3.5.2 includes version 3.1.1 of the JDT compiler. It can be found under the lib directory of the directory created when extracting the project ZIP file. The file to add to your CLASSPATH is jdt-compiler-3.1.1.jar.
This file cannot be downloaded separately; therefore, if we need to execute our code under a JRE. We need to download the JasperReports project ZIP file because it includes this file needed for report compilation.
When using a JDBC datasource, which is the most common datasource for JasperReports generated reports, the appropriate JDBC driver for our specific RDBMS is needed. The following table lists popular relational database systems and the required JAR files to add to the CLASSPATH. The exact filenames may vary depending on the version, target JDK, and supported JDBC version. The filenames shown here reflect the latest stable versions targeted to the latest available JDK and the latest available version of JDBC at the time of writing.
Driver JAR Files
JavaDB/Derby (included with JDK 1.6+)
sqljdbc_1.2.2828.100_enu.exe (for Windows systems)
sqljdbc_1.2.2828.100_enu.tar.gz (for Unix systems)
The JasperReports project file includes the JDBC driver for HSQLDB. Consult your RDBMS documentation for information on where to download the appropriate JDBC driver for your RDBMS.
iText is an open source library for creating and manipulating PDF files. It is needed in our CLASSPATH only if we want to export our reports to PDF or RTF format. Version 3.5.2 of the JasperReports project file includes iText version 2.1.0; the file to add to your CLASSPATH is iText-2.1.0.jar.
The iText library can be downloaded separately from http://www.lowagie.com/iText/.
JFreeChart is an open source library for creating professional looking charts, including 2D and 3D pie charts, 2D and 3D bar charts, and line charts. It is needed in our CLASSPATH only if we intend to add charts to our reports. JFreeChart 1.0.12 can be found on the lib directory inside the JasperReports project file version 3.5.2. The file to add to the CLASSPATH is jfreechart-1.0.12.jar.
JFreeChart can be downloaded separately from http://www.jfree.org/jfreechart/.
JExcelApi is a Java library that allows Java applications to read, write, and modify Microsoft Excel files. We need JExcelApi in our CLASSPATH only if we need to export our reports to XLS format. JasperReports 3.5.2 includes JExcelApi version 2.6. To add XLS exporting capabilities to our reports, the file we need to add to our CLASSPATH is jxl-2.6.jar.
JExcelApi can be downloaded separately from http://jexcelapi.sourceforge.net/.
This article covered the required and optional libraries needed to add reporting capabilities to Java applications. All the libraries covered in this article are needed at both compile time and runtime. The article provided an explanation of the different files available for downloading on JasperReports' web site and in which conditions it is appropriate to use them. We also saw which libraries are required for report compilation under a JDK and the additional libraries required when compiling JRXML templates under a JRE. Besides, we also learned which libraries are required when using JDBC datasources for our reports, and finally the libraries required when exporting our reports to several formats.
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About the Author :
David Heffelfinger is the Chief Technology Officer of Ensode Technology, LLC, a software consulting firm based in the greater Washington DC area. He has been architecting, designing and developing software professionally since 1995 and has been using Java as his primary programming language since 1996. He has worked on many large scale projects for several clients including the US Department of Homeland Security, Freddie Mac, Fannie Mae, and the US Department of Defense. He has a Masters degree in Software Engineering from Southern Methodist University. David is editor in chief of Ensode.net (http://www.ensode.net), a website about Java, Linux, and other technology topics.
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