May 2010 Posts

Connecting Remote EJB3 from a Servlet with WebLogic 10.3

Right now i’m trying to connect 2 different applications that located in a different server. Im using remote EJB3 to connecting them, with Apache Tomcat as server 1 and WebLogic 10.3 as server 2. Im using Netbeans 6.8 as primary IDE for this test.

create an EJB Module Project from Netbeans IDE, and create these files

first is the remote interface

package com.edw.ejb3;

import javax.ejb.Remote;

@Remote
public interface HelloEJBRemote {
    String sayHello(final String name);    
}

and the ejb implementation

package com.edw.ejb3;

import javax.ejb.Stateless;

@Stateless(mappedName="HelloEJB")
public class HelloEJB implements HelloEJBRemote {
    public String sayHello(final String name) {
        return "Hello "+name+" how do you do?";
    }
}

Package it as JAR or EAR, start Weblogic then use Admin Console (default: http://localhost:7001/ ) to deploy the EJB.
deployment

and to make sure, you can check EJB’s JNDI
ejb's jndi

next is creating a Web Project, dont forget to include your EJB project to your Web Project’s library.

create a servlet file to perform a connection to Remote EJBs.

package ejb;

import com.edw.ejb3.HelloEJBRemote;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Hashtable;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class EJBServlet extends HttpServlet {

    @Override
   protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        try {

            Hashtable<String, String> env = new Hashtable<String, String>();
            env.put(Context.INITIAL_CONTEXT_FACTORY, "weblogic.jndi.WLInitialContextFactory");
            env.put(Context.PROVIDER_URL, "t3://localhost:7001");

            Context ic = new InitialContext(env);

            HelloEJBRemote remote = (HelloEJBRemote) ic.lookup("HelloEJB#com.edw.ejb3.HelloEJBRemote");

            out.println(remote.sayHello("Edwin"));

        } catch (Exception ex) {
            out.print(ex);
            ex.printStackTrace();
        } finally {
            out.close();
        }
    } 
}

and this is my web.xml configuration file

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" 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/web-app_2_5.xsd">
    <servlet>
        <servlet-name>EJBServlet</servlet-name>
        <servlet-class>ejb.EJBServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>EJBServlet</servlet-name>
        <url-pattern>/ejb</url-pattern>
    </servlet-mapping>
    <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
</web-app>

if you find this error,

javax.naming.NoInitialContextException: Cannot instantiate class: weblogic.jndi.WLInitialContextFactory [Root exception is java.lang.ClassNotFoundException: weblogic.jndi.WLInitialContextFactory]

it happen because you havent put wlfullclient.jar (WebLogic library) into your Apache Tomcat’s library folder. You can find it in your Weblogic installation folder ({weblogic}\server\lib) or you can create it your self, by executing wljarbuilder.jar.

java -jar wljarbuilder.jar

tomcat libs

you can test your app by running your web project from your IDE.
web content

this is my netbeans project structure
Netbeans Project Structure

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A Simple Swing and iBatis Integration Example

According to Wikipedia, iBATIS is a persistence framework which automates the mapping between SQL databases and objects in Java, .NET, and Ruby on Rails. In Java, the objects are POJOs (Plain Old Java Objects). The mappings are decoupled from the application logic by packaging the SQL statements in XML configuration files. The result is a significant reduction in the amount of code that a developer needs to access a relational database using lower level APIs like JDBC and ODBC.

Here, we are trying to create a simple java application using iBatis framework. Im using Netbeans as my IDE and MySql for my database. First of all, we create a simple “test” database, and “contoh” table consisting of two varchar fields.

CREATE DATABASE 'test'
USE 'test'

CREATE TABLE 'contoh' (
  'nama' varchar(30) NOT NULL,
  'alamat' varchar(100) DEFAULT NULL,
  PRIMARY KEY ('nama')
) 

next step is creating a java bean for database mapping

package com.edw.bean;

public class Contoh {

    private String nama;
    private String alamat;

    public String getAlamat() {
        return alamat;
    }

    public void setAlamat(String alamat) {
        this.alamat = alamat;
    }

    public String getNama() {
        return nama;
    }

    public void setNama(String nama) {
        this.nama = nama;
    }
    
}

and an xml mapping for database queries, i name it contoh.xml, and place it in

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE sqlMap PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN" "http://ibatis.apache.org/dtd/sql-map-2.dtd" >
<sqlMap namespace="contoh" >

  <insert id="insertContoh" parameterClass="com.edw.bean.Contoh" >
    insert into contoh (nama, alamat)
    values (#nama:VARCHAR#, #alamat:VARCHAR#)
  </insert>
</sqlMap>

and one xml file to contain all of our basic database connection and configuration files

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE sqlMapConfig
PUBLIC "-//ibatis.apache.org//DTD SQL Map Config 2.0//EN"
"http://ibatis.apache.org/dtd/sql-map-config-2.dtd">

<sqlMapConfig>
    <settings
        useStatementNamespaces="true"
        lazyLoadingEnabled="true"
        enhancementEnabled="true"
        maxSessions="20"
        />

    <transactionManager type="JDBC" commitRequired="false">
        <dataSource type="SIMPLE">

            <property name="SetAutoCommitAllowed" value="false"/>
            <property name="DefaultAutoCommit" value="false"/>
            
            <property name="JDBC.Driver" value="com.mysql.jdbc.Driver"/>
            <property name="JDBC.ConnectionURL" value="jdbc:mysql://localhost/test"/>
            <property name="JDBC.Username" value="root"/>
            <property name="JDBC.Password" value=""/>
   
        </dataSource>
    </transactionManager>


    <!-- dont forget to register your sql map configs -->
    <sqlMap resource="com/edw/sqlmap/contoh.xml"/>

</sqlMapConfig>

dont forget to register you xml queries here (line 28), or iBatis wont find it. And as you can see, at line 11, we can set our maximum session to database. 20 maxSessions means, there wont be more than 20 concurrent connection to database. Dont worry, iBatis can also connect to your connection pooling or JNDI as Datasource.

next step is, we create a singleton java class, to load our iBatis configuration.

package com.edw.config;

import com.ibatis.common.resources.Resources;
import com.ibatis.sqlmap.client.SqlMapClient;
import com.ibatis.sqlmap.client.SqlMapClientBuilder;

import java.io.IOException;
import java.io.Reader;

public class SqlMapConfig {

    protected static final SqlMapClient sqlMap;

    static {
        try {
            Reader reader = Resources.getResourceAsReader("com/edw/sqlmap/sqlmapconfig.xml");
            sqlMap = SqlMapClientBuilder.buildSqlMapClient(reader);
        } catch (IOException e) {
            throw new RuntimeException("Fatal Error, ga dapet sqlmapconfignya.  Cause: " + e, e);
        } catch (Exception e){
            throw new RuntimeException("Fatal Error.  Cause: " + e, e);
        }
    }

    public static SqlMapClient getSqlMap() {
        return sqlMap;
    }
}

and after that, we create our UI Class. Im using a simple Swing class for example.

package com.edw.ui;

import com.edw.bean.Contoh;
import com.edw.config.SqlMapConfig;
import com.ibatis.sqlmap.client.SqlMapClient;
import java.awt.Container;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.SQLException;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;

public class FrameUtama extends JFrame implements ActionListener {

    private JTextField txtNama = new JTextField();
    private JTextField txtAlamat = new JTextField();
    private JButton cmdButton = new JButton("Save");

    public FrameUtama(){
        setLayout(new GridLayout(3, 3));
        Container con = this.getContentPane();
        con.add(new JLabel("nama : "));
        con.add(txtNama);
        con.add(new JLabel("Alamat : "));
        con.add(txtAlamat);
        con.add(cmdButton);

        cmdButton.addActionListener(this);
    }

    public void actionPerformed(ActionEvent e) {

    }

    public static void main(String[] edw) {
        FrameUtama frameUtama = new FrameUtama();
        frameUtama.setVisible(true);
        frameUtama.setSize(300,150);
        frameUtama.setLocationRelativeTo(null);
    }

}

and we just put this simple snippet code to connect our Swing UI code to database via iBatis.

 public void actionPerformed(ActionEvent e) {
        if(e.getSource() == cmdButton){
            Contoh contoh = new Contoh();
            contoh.setNama(txtNama.getText());
            contoh.setAlamat(txtAlamat.getText());

            SqlMapClient sqlMapClient = SqlMapConfig.getSqlMap();
            try {
                sqlMapClient.insert("contoh.insertContoh", contoh);
                System.out.println("Success");
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
        }
    }

well, this is the project file structure in NB 6.8.
my ibatis project structure

and this is the UI layout
Application GUI

this is what happen if we submit a data
successfully submit data

the data we submitted is in the database
mysql data

dont forget to download ibatis jars here, im using iBatis 2.3.4 currently.
Thanks.

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