October 19, 2012

Updating EclipseLink in WebLogic

JSON binding was added to EclipseLink in version 2.4.  If you are using a version of that does not contain this version (i.e. WebLogic 10.3.4 (11g) contains EclipseLink 2.1.2), then by default you won't have access to this functionality. The recommended solution to this problem is to create a shared library in WebLogic for the newer release of EclipseLink.


Create the Shared Library

WebLogic has the concept of shared libraries. These are deployed as an EAR. Below is what the EAR will look like for creating a shared library for EclipseLink 2.4.

EclipseLink24_SharedLibrary.ear 
  • lib/eclipselink.jar 
  • META-INF/application.xml 
  • META-INF/MANIFEST.MF 
  • META-INF/weblogic-application.xml
application.xml
 
<application>
  <display-name>EclipseLink 2.4 Shared Library</display-name>
  <module>
    <java></java>
  </module>
</application>

MANIFEST.MF

Manifest-Version: 1.0
Ant-Version: Apache Ant 1.8.2
Created-By: 1.7.0_04-b21 (Oracle Corporation)
Extension-Name: EclipseLink-2.4.0
Specification-Version: 2.4.0
Implementation-Version: 2.4.0.v20120608-r11652

weblogic-application.xml 

<weblogic-application>
  <prefer-application-packages>
    <package-name>org.eclipse.persistence.*</package-name>
  </prefer-application-packages>
</weblogic-application>

Use the Shared Library

Once the shared library has been deployed, you need to configure your enterprise applications to use it.

SampleApplication.ear
  • META-INF/MANIFEST.MF 
  • META-INF/weblogic-application.xml 
  • SampleApplication.war 

weblogic-application.xml 

The weblogic-application.xml file is used to reference the shared library. The entries in the library-ref element need to match the corresponding entries from MANIFEST.MF in the shared library.

<?xml version="1.0" encoding="UTF-8"?>
<wls:weblogic-application xmlns:wls="http://xmlns.oracle.com/weblogic/weblogic-application" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/javaee_5.xsd http://xmlns.oracle.com/weblogic/weblogic-application http://xmlns.oracle.com/weblogic/weblogic-application/1.2/weblogic-application.xsd">
    <!--weblogic-version:10.3.4-->
    <wls:application-param>
        <wls:param-name>webapp.encoding.default</wls:param-name>
        <wls:param-value>UTF-8</wls:param-value>
    </wls:application-param>
    <wls:library-ref>
        <wls:library-name>EclipseLink-2.4.0</wls:library-name>
        <wls:specification-version>2.4.0</wls:specification-version>
        <wls:implementation-version>2.4.0.v20120608-r11652</wls:implementation-version>
        <wls:exact-match>true</wls:exact-match>
    </wls:library-ref>
</wls:weblogic-application>

TestServlet

Below is a test servlet that you could include in the WAR to test the EclipseLink version. 

package com.example;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.*;

public class TestServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    public TestServlet() {
        super();
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out.append("<html><body>");
        out.append(org.eclipse.persistence.Version.getVersion());
        out.append("</body></html>");
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    }

}

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