sairajitha/spring-mvc-jasper

Jasper Reports with Spring MVC

1. Introduction

With advancements in HTML, CSS, JavaScript, web browser capabilities and Internet speeds, more and more enterprise functionality is being migrated to the web. This has led to an increase in the amount of data being made available to enterprise users over the web and therefore an increased demand for rich reporting capabilities in web applications.

Spring MVC is a popular Java framework for building web applications. It runs well across Java application servers and provides tight integration with loads of popular Java tools such as source code editors (Eclipse, IDEA, Netbeans) and build managers (Maven, ANT, Ivy, Gradle). It also usually works well with most languages that work on the JVM (for example, Scala and Groovy), making it popular for developing web applications on the JVM.

Jasper Reports is a Java based reporting library boasting of a fairly comprehensive set of reporting features, a visual report design tool, a flexible report generation framework, support for multiple report formats such as HTML, XHTML, PDF, Microsoft Excel 97 (.xls), Microsoft Excel 2000 (.xlsx), CSV,Rich Text, Open Data Format (.odf) and more. The great thing about Jasper Reports is that reports designed using the visual editor looks exactly the same in all formats. This allows developers to produce develop-once, deliver-anywhere reports that different types of users can work with on different devices.

This sample application demonstrates one possible way of adding Jasper Reports to a Spring MVC application. The primary goal of this sample is to demonstrate how Jasper Reports can be integrated in a Spring-MVC application that has multiple logical layers for maintainability and scalability. For other integration possibilities see the last section below.

2. Overview

This sample application contains two types of reports:

1. Tabular
2. Chart/Graph

2.1. Context

The sample application has been developed for a fictitious company called Coffee Inc. a high-street shop that sells coffee and related items. The reports generated by the application are meant for use by the employees of Coffee Inc.

2.2. Tabular report - Order History

This report shows all orders received by Coffee Inc. It contains the following table:

S. No.	Order Date	Customer Name	Order Total

2.3. Chart report - Order Summary

This report shows a summary of all orders received by Coffee Inc., grouped by month. For every month, it shows the total amount received by Coffee Inc.

3. Running the application

The following pre-requisites need to be met in order to run this application:

1. JDK 6.0+
2. Apache Maven 3.0.4+

Once these are installed and the application code has been checked out or downloaded from Git, the application can be run by issuing the following command:

mvn clean tomcat7:run -Ptomcat

This will compile the application (after downloading all necessary libraries) and run an embedded Tomcat instance on port 8080. The application can then be accessed on http://localhost:8080 using any web browser.

The reports can be accessed from the navigation menu on the left-hand-side of the page. Each report can be accessed in HTML, PDF and Microsoft Excel '97 formats.

The application also be run against an embedded Jetty instance as well as:

mvn clean jetty:run -Pjetty

4. Report files

The report designs can be found in files under the folder src/main/resources/org/example/report/order.

5. Explanation of the code

This application uses Scala, a programming language that runs on the JVM. Scala was chosen primarily due to its brevity that allows relatively small prototypes to be developed quickly (compared to developing the same prototype with Java). It reduces the amount of repetitive code typically required to write a Spring MVC based web application, without sacrificing any integration opportunities between the frameworks used on the bespoke code written.

The application is a regular Spring MVC web application, with the following notable additions:

1. A helper class for generating a report from a Jasper Report template and report data;
2. A helper servlet for displaying charts and graphics in an HTML report;
3. web.xml configuration for the helper servlet.

The reports are generated by Spring MVC Controller classes that can be found under src/main/scala/org/example/web/controller/report. Please refer to Spring MVC documentation in case you are new to MVC and need more explanation on what a Controller class is or how it works.

The Controller classes in turn call a class called JasperReportGenerator that can be found under src/main/scala/org/example/web/report/jasper. This class is responsible for generating reports in the required format (HTML, PDF or Microsoft Excel) from a report template and report data. It has been written in a Java-like manner to make it easy for readers to understand the flow and get familiar with Jasper Reports API.

Controller classes pass data to JasperReportGenerator as a java.util.Collection of objects, which is then passed on to the Jasper Reports API to be merged with the report template. This strategy allows the reports to be completely decoupled from the source of the data used to generate them. Data can be pulled out of a relational database, local files, external systems, email systems, and so on and be passed on to the reports in a consistent and reliable way, without the reports having to manage the connectivity with the data source(s). Not allowing Jasper Reports direct access to the underlying data stores also adds to the security of the application as any bug in Jasper Reports, malformed user requests or hacking attempts cannot expose the data stores directly. Further, since the requests for reports go through multiple application layers, security hazards such as SQL Injection can be prevented easily.

There is also a small bit of configuration in the web.xml file for the application:

<web-app>
  <servlet>
    <servlet-name>jasper-report-image</servlet-name>
    <servlet-class>org.example.web.servlet.jasper.GraphicsServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>jasper-report-image</servlet-name>
    <url-pattern>/report/graphics</url-pattern>
  </servlet-mapping>
</web-app>

This part of the configuration maps the URL /report/graphics to the servlet org.example.web.servlet.jasper.GraphicsServlet. This servlet is responsible for adding charts and graphics to HTML reports. Internally, it uses the data passed to a report to generate images for the charts embedded inside an HTML report.

6. Modifying the source code

The source code can be modified using any popular Java IDE, such as, Eclipse, IDEA or Netbeans.

7. License

This sample application and its associated source code in its entirety is being made available under the following licensing terms.

Copyright (C) 2014

Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in the
Software without restriction, including without limitation the rights to use, copy,
modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
and to permit persons to whom the Software is furnished to do so, subject to the
following conditions:

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

8. Alternate integration options

The current Jasper Reports documentation available online suggests generating charts and graphics using a third-party library such as JFreeChart and embedding the generated image directly into a Jasper Report. Although this approach works, it adds development complexity as developers need to learn a framework such as JFreeChart in addition to learning Jasper Reports. Additionally, for every chart or graphic to be included in reports, the developers would have to write code. All of this would add significant development overhead, making this option less practical than the one used in this sample application, which involves generating graphics using a simple servlet.