跳至主要内容

Generate reports with Seam 3 Reports and Apache Velocity

Seam 3 provides a collection of standard CDI extensions. Seam3 report module bridges CDI and several report engines, such as

Basic Configuration

Assume you have already created a Maven based Java EE 6 application. If not, you can create one using JBoss Forge.
Add Seam 3 reports related dependencies into your pom.xml.
  <dependency>
        <groupId>org.jboss.seam.reports</groupId>
        <artifactId>seam-reports-api</artifactId>
        <version>${seam-reports-version}</version>
  </dependency>

  <!-- If you are using Jasper Reports, add the following dependency --> 
  <dependency>
        <groupId>org.jboss.seam.reports</groupId>
        <artifactId>seam-reports-jasper</artifactId>
        <version>${seam-reports-version}</version>
  </dependency>
Generally, in order to generate a JasperReports based report in a Seam 3/Java EE6 project, you could consider the following steps:
  1. Create JasperRoports jrxml file using iReports or JasperStudio
  2. Compile jrxml file to PDF
You can use the official JaperReports Studio(for Eclipse users) or iReports(for NetBeans users) to create the reports template source file.
In your java code, inject JasperReports compiler to compile the jasperReports source, and JasperReports renderer to render the compiled result.
  @Inject
  @Jasper
  private transient ReportCompiler compiler;

  @Inject
  @PDF
  @Jasper
  private transient ReportRenderer pdfRenderer;
The @Jasper annotation states we will use JasperReports as report engine, @PDF is the final generated document format.
    ReportDefinition report;
    try {
        report = compiler.compile(<JasperReporst source>);
        Report reportInstance = report.fill(<JR DataSource>, null);

        pdfRenderer.render(reportInstance,
                externalContext.getResponseOutputStream());
    } catch (ReportException e) {
        e.printStackTrace();
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
JRDataSource is a JasperReports specified "datasource" which is responsible of gathering the data for report generation. JasperReports provides several implementations natively, please refer to the JRDataSource javadoc for more detailed info. In this case, we have got a list, we can use JRBeanCollectionDataSource to wrap the existing list and use it in this reports.
Everything works well.
But personally, I dislike the jrxml syntax and do not want to use jrxml syntax to fill data, I only want to use JasperReports as report engine. I am familiar with Apache Velocity, is possible using Velocity as template and fill data?

Improve the codes with Apache Veloctiy

Now change the report generation process slightly, and introduce an extra step to generate the pure jrxml.
  1. Create a velocity template source(embed velocity syntax into jrxml)
  2. Convert the velocity template to pure jrxml
  3. Compile the jrmxl to PDF.
Create a jrxml firstly, and embed the velocity syntax.
  <detail>
        <band height="125" splitType="Stretch">
            #set( $y = 0 )
            #foreach($obj in $contacts)
            <staticText>
                <reportElement  x="0" y="$y" width="177" height="20"/>
                <textElement textAlignment="Left" verticalAlignment="Middle"/>
                <text><![CDATA[$!obj.name]]></text>
            </staticText>
            <staticText>
                <reportElement  x="177" y="$y" width="200" height="20"/>
                <textElement textAlignment="Left" verticalAlignment="Middle"/>
                <text><![CDATA[$!obj.phoneNumber]]></text>
            </staticText>
            <staticText>
                <reportElement x="377" y="$y" width="178" height="20"/>
                <textElement textAlignment="Left" verticalAlignment="Middle"/>
                <text><![CDATA[$!obj.emailAddress]]></text>
            </staticText>
            #set($y = $y + 20)
            #end
        </band>
    </detail>
In java codes, firstly fill data in the velocity based jrxml, then convert it to pure jrxml, finally compile it to PDF document.
    InputStream sourceTemplate = resourceProvider
            .loadResourceStream(reportTemplate);

    Map<String, Object> _values = new HashMap<String, Object>();
    _values.put("contacts", contacts);
    _values.put("usd", "$");

    String stringReport = new VelocityTemplate(sourceTemplate,
            velocityContext).merge(_values);

    if (log.isDebugEnabled()) {
        log.debug("report source file content@" + stringReport);
    }
    // source
    ReportDefinition report;
    try {
        report = compiler.compile(new ByteArrayInputStream(stringReport
                .getBytes("UTF-8")));
        Report reportInstance = report.fill(new JREmptyDataSource(), null);

        pdfRenderer.render(reportInstance,
                externalContext.getResponseOutputStream());
    } catch (ReportException e) {
        e.printStackTrace();
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
Note, the velocity support is from the Seam3 mail module.
In the Seam3 repository, there is a standalone renderer module for rendering template, but it is not released a stable version at the moment.
So you have to add Seam3 mail dependencies in your pom.xml.
    <dependency>
        <groupId>org.jboss.seam.mail</groupId>
        <artifactId>seam-mail-api</artifactId>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>org.jboss.seam.mail</groupId>
        <artifactId>seam-mail</artifactId>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>org.apache.velocity</groupId>
        <artifactId>velocity</artifactId>
    </dependency>

Run the project

I assume you have installed the latest Oracle JDK 7, JBoss AS 7.1.1.Final and Apache Maven 3.0.4.
  1. Check out the complete codes from github.com.
    git clone git://github.com/hantsy/seam3-report-demo.git
    
  2. Start JBoss AS from command line.
    <JBOSS_HOME>\bin\standalone.bat
    
  3. Deploy the application into the running JBoss AS.
    mvn clean package jboss-as:deploy
    
  4. Open your browser and go to http://localhost:8080/seam3-reports-demo.

评论

此博客中的热门博文

Build a Reactive application with Angular 5 and Spring Boot 2.0

I have created a post to describe Reactive programming supports in Spring 5 and its subprojects, all codes of this article are updated the latest Spring 5 RELEASE, check spring-reactive-sample under my Github account.
In this post, I will create a simple blog system, including:
A user can sign in and sign out.An authenticated user can create a post.An authenticated user can update a post.Only the user who has ADMIN role can delete a post.All users(including anonymous users) can view post list and post details.An authenticated user can add his comments to a certain post. The backend will be built with the latest Spring 5 reactive stack, including:
Spring Boot 2.0, at the moment the latest version is 2.0.0.M7Spring Data MongoDB supports reactive operations for MongoDBSpring Session adds reactive support for WebSessionSpring Security 5 aligns with Spring 5 reactive stack The frontend is an Angular based SPA and it will be generated by Angular CLI.
The source code is hosted on Github, …

Activating CDI in JSF 2.3

Activating CDI in JSF 2.3 When I upgraed my Java EE 7 sample to the newest Java EE 8, the first thing confused me is the CDI beans are not recoganized in Facelects template in a JSF 2.3 based web applicaiton, which is working in the development version, but in the final release version, they are always resolved as null. I filed an issue on Mojarra and discussed it with the developers from communities and the JSF experts.
According to the content of README, In a JSF 2.3 application, to activate CDI support, declaring a 2.3 versioned faces-config.xml and adding javax.faces.ENABLE_CDI_RESOLVER_CHAIN in web.xml is not enough, you have to declare @FacesConfig annotated class to enable CDI.
Here is the steps I created a workable JSF 2.3 applicatoin in Java EE 8.
Create a Java web application, this can be done easily by NetBeans IDE, or generated by Maven archetype, for exmaple.
$ mvn archetype:generate -DgroupId=com.example -DartifactId=demo -DarchetypeArtifactId=maven-archetype-w…

JSF 2.3:Websocket support

Websocket support One of the most attractive features is JSF 2.3 added native websocket support, it means you can write real-time applications with JSF and no need extra effort.
To enable websocket support, you have to add javax.faces.ENABLE_WEBSOCKET_ENDPOINT in web.xml.
<context-param> <param-name>javax.faces.ENABLE_WEBSOCKET_ENDPOINT</param-name> <param-value>true</param-value> </context-param> Hello Websocket Let's start with a simple example.
@ViewScoped@Named("helloBean") publicclassHelloBeanimplementsSerializable { privatestaticfinalLoggerLOG=Logger.getLogger(HelloBean.class.getName()); @Inject@PushPushContext helloChannel; String message; publicvoidsendMessage() { LOG.log(Level.INFO, "send push message"); this.sendPushMessage("hello"); } privatevoidsendPushMessage(Objectmessage) { helloChannel.send(""+ message +" at &…