Book Image

JasperReports for Java Developers

Book Image

JasperReports for Java Developers

Overview of this book

JasperReports is the world's most popular embeddable Java open source reporting library, providing Java developers with the power to easily create rich print and web reports. This book shows you exactly how to get started, and develop the skills to get the most from JasperReports. The book steers you through each point of report setup, to creating, designing, formatting, and exporting reports with data from a wide range of datasources, and integrating JasperReports with other Java frameworks. Starting with the basics of adding reporting capabilities to your application, and creating report templates you will first see how to produce your reports through the use of JRXML files, custom ANT targets, and then see preview them in both the browser and the native browser of JasperReports. Getting data into your reports is the next step, and you will see how to get data from a range of datasources, not only databases, but XML files, and Java Objects, among others. You will create better looking reports with formatting and grouping, as well as adding graphical elements to the report. You will export your reports to a range of different formats, including PDF and XML. Creating reports will be made even easier with a walkthrough of the iReport Designer visual designing tool. To round things off, you will see how to integrate your reports with other Java frameworks, using Spring or Hibernate to get data for the report, and Java Server Faces or Struts for presenting the report.
Table of Contents (13 chapters)
12
Index

Report Variables

When we wrote the report in the previous section, we had to type the following expression twice:

$F{fixed_wing_single_engine_cnt}.intValue() +
$F{fixed_wing_multiple_engine_cnt}.intValue())

This expression was typed once to calculate the number of fixed-wing aircraft reported, and again to calculate the total number of aircraft reported. This duplication is not a good thing, since if we need to change the expression for any reason we would have to do it twice. JasperReports allows us to assign report expressions to a variable, eliminating the need to type the expression multiple times. The following JRXML template is a modified version of the one we wrote in the previous section. This version takes advantage of report variables to eliminate the duplicate expression.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE jasperReport PUBLIC "//JasperReports//DTD Report Design//EN" "http://jasperreports.sourceforge.net/dtds/jasperreport...