Struts 2 JSON Plugin

Struts 2 JSON Plugin focuses in simplicity and, therefore, all of its functionalities have as main goal solve the developer's problem in the less intrusive way.

Some reasons you might want to use:

• Simple, powerful, flexible.
• Serializable with Gson (hey, this is great!).
• Support for OSGi (Struts OSGi Plugin).
• Extensive documentation, and great community support.

Using it

1. In a Maven project's pom.xml file:

<dependency>
    <groupId>es.cenobit.struts2.json</groupId>
    <artifactId>struts2-json-plugin</artifactId>
    <version>2.3.16</version> <!-- or last version Struts 2.x -->
</dependency>

2. Or put struts2-json-plugin-VERSION.jar and dependencies in your WEB-INF/lib folder.
3. In your project create actions.

Domain

public class Bar {

    private Long id;
    private String title;
    private String description;
    private Date pubDate;
    private Boolean status;

    public Bar(Long id, String title, String description, Date pubDate, Boolean status) {
        super();
        this.id = id;
        this.title = title;
        this.description = description;
        this.pubDate = pubDate;
        this.status = status;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public Date getPubDate() {
        return pubDate;
    }

    public void setPubDate(Date pubDate) {
        this.pubDate = pubDate;
    }

    public Boolean getStatus() {
        return status;
    }

    public void setStatus(Boolean status) {
        this.status = status;
    }

}

Action

public class IndexAction extends ActionSupport {

    private static final long serialVersionUID = -1411535978306393960L;

    @Json
    public Bar showBar() {
        Bar bar = new Bar(1L, "Mussum ipsum",
                " Mé faiz elementum girarzis, nisi eros vermeio, in elementis mé pra quem é amistosis quis leo",
                new Date(), Boolean.TRUE);
        return bar;
    }
}

struts.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
        "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
        "http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
    <constant name="struts.enable.DynamicMethodInvocation" value="false" />
    <constant name="struts.devMode" value="true" />

    <package name="default" namespace="/" extends="json-default">

        <action name="bar" class="es.cenobit.struts2.json.example.IndexAction" method="showBar" />

    </package>

</struts>

4. Testing

$ curl -i -X GET http://localhost:8080/struts2-json-plugin-example/bar
HTTP/1.1 200 OK
Content-Type: application/json;charset=UTF-8
Transfer-Encoding: chunked
Server: Jetty(8.1.7.v20120910)

{"id":1,"title":"Mussum ipsum","description":" Mé faiz elementum girarzis, nisi eros vermeio, in elementis mé pra quem é amistosis quis leo","pub_date":"Jan 3, 2014 11:13:50 AM","status":true}

For more tests see Examples.

Actions in jar files

By default the Json plugin will not scan jar files for actions. For a jar to be scanned, its URL needs to match at least one of the regular expressions in struts.json.action.includeJars. In this example myjar1.jar and myjar2.jar will be scanned:

<constant name="struts.json.action.includeJars" value=".*?/myjar1.*?jar(!/)?,.*?/myjar2*?jar(!/)?"

Note that the regular expression will be evaluated against the URL of the jar, and not the file name, the jar URL can contain a path to the jar file and a trailing "!/".

Automatic configuration reloading

The Json plugin can automatically reload configuration changes, made in classes the contain actions, without restarting the container. This is a similar behavior to the automatic xml configuration reloading. To enable this feature, add this to your struts.xml file:

<constant name="struts.devMode" value="true"/>
<constant name="struts.json.classes.reload" value="true" /> 

This feature is experimental and has not been tested on all container, and it is strongly advised not to use it in production environments.

JBoss

When using this plugin with JBoss, you need to set the following constants:

<constant name="struts.json.exclude.parentClassLoader" value="true" />
<constant name="struts.json.action.fileProtocols" value="jar,vfsfile,vfszip" />

Jetty (embedded)

When using this plugin with Jetty in embedded mode, you need to set the following constants:

<constant name="struts.json.exclude.parentClassLoader" value="false" />
<constant name="struts.json.action.fileProtocols" value="jar,code-source" />

Support for OSGi

With Spring managed beans to error:

ERROR: Bundle es.cenobit.struts2.osgi-mod [1] Error starting file:/home/nycholas/app/apache-tomcat-7.0.42/webapps/struts-osgi-app/WEB-INF/classes/bundles/3/struts-osgi-mod-1.0-SNAPSHOT.jar (org.osgi.framework.BundleException: Unresolved constraint in bundle es.cenobit.struts2.osgi-mod [1]: Unable to resolve 1.0: missing requirement [1.0] osgi.wiring.package; (&(osgi.wiring.package=es.cenobit.struts2.json.annotations)(version>=2.3.0)(!(version>=3.0.0))))
org.osgi.framework.BundleException: Unresolved constraint in bundle es.cenobit.struts2.osgi-mod [1]: Unable to resolve 1.0: missing requirement [1.0] osgi.wiring.package; (&(osgi.wiring.package=es.cenobit.struts2.json.annotations)(version>=2.3.0)(!(version>=3.0.0)))
    at org.apache.felix.framework.Felix.resolveBundleRevision(Felix.java:3826)
    at org.apache.felix.framework.Felix.startBundle(Felix.java:1868)
    at org.apache.felix.framework.Felix.setActiveStartLevel(Felix.java:1191)
    at org.apache.felix.framework.FrameworkStartLevelImpl.run(FrameworkStartLevelImpl.java:295)
    at java.lang.Thread.run(Thread.java:722)

To fix this add this line to MANIFEST.MF:

DynamicImport-Package: es.cenobit.struts2.json.annotations

Or if using The Apache Felix maven plugin (see below for details):

<DynamicImport-Package>es.cenobit.struts2.json.annotations</DynamicImport-Package>

Notes

WARNING: Struts Convention Plugin and Struts Json Plugin doesn't work together

TODO

• Integration for Struts Convention Plugin
• Interceptor Json (validation, ...)
• Tests
• Documentation
• Examples

Project Information

• Author: Cenobit Technologies, Inc.
• Version: 1.0 of 2014/01/02
• License: Apache License 2.0