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Thursday November 10, 2005

How to develop CMP beans for JBoss in NetBeans I have recently read one question about developing CMP beans for Jboss in NetBeans. The user asked for some details that are related to CMP beans for JBoss, e.g. setup database in Jboss, server specific deployment descriptors, ... I decided to write simple tutorial about developing CMP beans for JBoss.
Let's start to develop simple application that manages issues for your product. The issues are persisted in MySQL database, application tier has two beans, one is CMP bean that represents issue and stateless session bean with remote and local interface. This bean represents facade for business logic. The client is simple J2SE client that invokes business methods in session bean. We will develop application tier today and client tomorrow. Eneterpise module sources are avalaible here.

• First, we need create table in MySQL database. I created the table with following structure:

   
        CREATE TABLE ISSUE (
        ID SERIAL,
        TYPE CHAR(1),
        PRIORITY SMALLINT,
        OWNER VARCHAR(20),
        SUMMARY VARCHAR(30),
        PRIMARY KEY(ID));
     

  If you don't want to creat the table manually, you can download sources and in a directory setup is file setup.sql that creates table and inserts values into table. You can the command mysql -u your_user -p < setup.sql.
• Copy and edit file $JBOSS_HOME/docs/examples/jca/mysql-ds.xml in $JBOSS_HOME/server/default/deploy. In this file you should specify url for DB, user and password. Don't forget copy MySQL JDBC driver in server's lib directory.
• Create new EJB module and generate CMP bean from ISSUE table. Under configuration node you can see dbschema that isn't needed for Jboss server. The dbschema is Sun App server specific. You can delete this file.
• NetBeans doesn't creates server specific file that is used for O-R mapping. Therefore, we should create it manually. Create new jbosscmp-jdbc.xml file in src/conf directory. I don't explain the file in this post, you can check mentioned sources. Shortly, this file includes information about JNDI name for MySQL datasource and mapping CMP fields to database columns and bean name to table name.
• Select entity node in project tab, right click and invoke Generate DTO. This TO will be used in communication between client and facade.
  
  
• Deploy the project to Jboss server. In the Jboss output window you can see messages about successful deployment:
  

  Bound EJB LocalHome 'IssueBean' to jndi 'local/IssueBean@17546680'
  Bound EJB LocalHome 'IZFacadeBean' to jndi 'local/IZFacadeBean@17637582'
  Bound EJB Home 'IZFacadeBean' to jndi 'IZFacadeBean'
  Deployed: file:/home.local/blaha/servers/jboss/server/default/deploy/Issues.jar