DynamicReports and Spring MVC integration

This is a tutorial on how to exploit DynamicReports reporting library in an existing Spring MVC based web application. It's a continuation to the previous post where DynamicReports has been chosen as the most appropriate solution to implement an export feature in a web application (for my specific use case). The complete code won't be provided here but only the essential code snippets together with usage remarks. Also I've widely used this tutorial that describes a similar problem for an alternative reporting library.

So let's turn to the implementation description and start with a short plan of this how-to:

1. Adding project dependencies.
2. Implementing the Controller part of the MVC pattern.
3. Modifying the View part of the MVC pattern.
4. Modifying web.xml.

Adding project dependencies
I used to apply Maven Project Builder throughout my Java applications, thus the dependencies will be provided in the Maven format.

Maven project pom.xml file:

    net.sourceforge.dynamicreports
    dynamicreports-core
    2.3.1
    
        
            net.sf.barcode4j
            barcode4j
        
        
            com.sun.xml.bind
            jaxb-impl
        
        
            org.codehaus.castor
            castor
        
        
            eclipse
            jdtcore
        
        
            xml-apis
            xml-apis
        
        
            jfree
            jfreechart
        
        
            jfree
            jcommon
        
        
            bouncycastle
            bcprov-jdk14
        
        
            org.apache.poi
            poi-ooxml
        
    


    net.sourceforge.jexcelapi
    jxl
    2.6.12

Here I wittingly missed other dependencies (including Spring, etc) as this post is more about applying DynamicReports to existing Spring based application. I widely used exclusions in order to minimize the final build size and left only those dependencies that are required for exporting to Excel and PDF formats. Whether you have other needs, you'll have to modify this code for yourself.

Implementing the Controller part of the MVC pattern

First of all I need to mention there is an alternative way to integrate DynamicReports with your Java web application that is a more generic one - using Servlets. I'm going to cover this approach in the next post, meanwhile you can refer to a short DynamicReports tutorial. Our current approach is based on Spring MVC features and is a more elegant solution.

ExportSearchController.java:

package org.lagivan.prototype.web.controller;

import net.sf.dynamicreports.jasper.builder.JasperReportBuilder;
import net.sf.dynamicreports.report.exception.DRException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;

@Controller
@Scope("session")
@RequestMapping("/export")
public class ExportSearchController {

    private static final Logger log =
            LoggerFactory.getLogger(ExportSearchController.class);

    private static final String PARAMETER_ITEM_NAME = "itemName";
    private static final String PARAMETER_TYPE = "type";
    private static final String VALUE_TYPE_PDF = "pdf";
    private static final String VALUE_TYPE_XLS = "xls";

    private static final Map<String, String> FILE_TYPE_2_CONTENT_TYPE = 
            new HashMap<String, String>();
    static {
        FILE_TYPE_2_CONTENT_TYPE.put(VALUE_TYPE_PDF, "application/pdf");
        FILE_TYPE_2_CONTENT_TYPE.put(VALUE_TYPE_XLS, "application/vnd.ms-excel");
    }

    @Autowired
    private SearchController searchController;

    @RequestMapping(value = "", method = RequestMethod.GET)
    public void export(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
        String fileType = request.getParameter(PARAMETER_TYPE);
        log.info("Exporting {} report", fileType);

        response.setContentType(FILE_TYPE_2_CONTENT_TYPE.get(fileType));
        OutputStream out = response.getOutputStream();
        try {
            JasperReportBuilder jrb = createJasperReport();

            if (VALUE_TYPE_PDF.equals(fileType)) {
                jrb.toPdf(out);
            } else if (VALUE_TYPE_XLS.equals(fileType)) {
                jrb.toExcelApiXls(out);
            }
        } catch (DRException e) {
            throw new ServletException(e);
        }
        out.close();
    }

    private JasperReportBuilder createJasperReport() {
        // Here use DynamicReports API to build a report 
        // and fill it with a JRDataSource.
        // I used SearchController session bean
        // to get required search results data.
    }
}

Here I widely used Spring annotations to register a Spring web controller, set its scope and map web requests to a specific handler method. As soon as method ExportSearchController.export is called on incoming web request, it generates an Excel or PDF output as a response using specified request parameters. Everything is quite straightforward and looks clear.

Implementing the View part of the MVC pattern

This part can be implemented using a variaty of ways in your application. We used to exploit JSF technology in our projects using RichFaces component library. Thus, I'll provide xhtml source code snippet that you will have to adapt to your own case. It's a page with search results that uses SearchController managed bean mentioned above to execute search functionality and to render search results data in a table component.

searchresults.xhtml:

<rich:dataTable id="searchresults-table" value="#{searchController.data}" width="100%">
    <rich:column style="vertical-align: top;" width="36px;">
        <f:facet name="header">
            <h:panelGroup>
                <h:outputLink title="Export to Excel"
                              value="#{facesContext.externalContext.requestContextPath}/web/export?type=xls">
                    <h:graphicImage style="border: none;" value="/icons/xls_16.png"/>
                </h:outputLink>
                <h:outputLink title="Export to PDF"
                              value="#{facesContext.externalContext.requestContextPath}/web/export?type=pdf">
                    <h:graphicImage style="border: none;" value="/icons/pdf_16.png"/>
                </h:outputLink>
            </h:panelGroup>
        </f:facet>
    </rich:column>
</rich:dataTable>

So you can see here is a column header where I added links to execute export functionality. Being clicked, a link produces HTTP request to your mapped handler method and returns HTTP response with a report document.

Modifying web.xml

Finally I've forgot to mention the last required change. Spring MVC requires DispatcherServlet to be registered in your web.xml to handle mapped requests properly. Actually you may have some issues here related to other Spring servlets. For example, I've already had a MessageDispatcherServlet registered in my application for the purpose of webservices. Thus, I had to add an empty spring-servlet.xml file and the following code snippet to my web.xml.

web.xml:

    spring
    org.springframework.web.servlet.DispatcherServlet
    1



    spring
    /web/*