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<title>Packaging and deploying the Beans</title><link rel="stylesheet" href="styles.css" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/styles.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets Vimages/callouts/"><link rel="home" href="index.html" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/index.html" title="JBoss 3.0 Documentation"><link rel="up" href="ch05.html" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/ch05.html" title="Chapter 5. Using container-managed persistence"><link rel="previous" href="ch05s08.html" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/ch05s08.html" title="Creating the Beans"><link rel="next" href="ch05s10.html" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/ch05s10.html" title="Creating a test client "></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><table border="0" cellpadding="0" cellspacing="0" height="65"><tr height="65"><td rowspan="2"><img src="jboss.gif" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/jboss.gif" border="0"></td><td rowspan="2" background="gbar.gif" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/gbar.gif" width="100%" align="right" valign="top"><a href="index.html" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/index.html"><img src="doc.gif" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/doc.gif" border="0"></a><a href="ch05.html" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/ch05.html"><img src="toc.gif" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/toc.gif" border="0"></a><a href="ch05s08.html" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/ch05s08.html"><img src="prev.gif" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/prev.gif" border="0"></a><a href="ch05s10.html" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/ch05s10.html"><img src="next.gif" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/next.gif" border="0"></a></td></tr><tr></tr></table><div class="section"><a name="d0e1888"></a><div class="titlepage"><div><h2 class="title" style="clear: both"><a name="d0e1888"></a>Packaging and deploying the Beans</h2></div></div><p>Deploying an entity bean requires providing some extra information, in
addition to that required
for a session bean. This information is provided in the deployment descriptor
ejb-jar.xml</p><pre class="programlisting">
<?xml version="1.0"?>
<ejb-jar>
<display-name>MusicCDs</display-name>
<enterprise-beans>
<entity>
<description>Models a music CD</description>
<ejb-name>CDBean</ejb-name>
<home>org.jboss.docs.cmp.cd.interfaces.CDHome</home>
<remote>org.jboss.docs.cmp.cd.interfaces.CD</remote>
<ejb-class>org.jboss.docs.cmp.cd.bean.CDBean</ejb-class>
<persistence-type>Container</persistence-type>
<prim-key-class>java.lang.Integer</prim-key-class>
<reentrant>False</reentrant>
<cmp-field><field-name>id</field-name></cmp-field>
<cmp-field><field-name>title</field-name></cmp-field>
<cmp-field><field-name>artist</field-name></cmp-field>
<cmp-field><field-name>type</field-name></cmp-field>
<cmp-field><field-name>notes</field-name></cmp-field>
<primkey-field>id</primkey-field>
</entity>
<session>
<description>Models a music CD collection</description>
<ejb-name>CDCollectionBean</ejb-name>
<home>org.jboss.docs.cmp.cd.interfaces.CDCollectionHome</home>
<remote>org.jboss.docs.cmp.cd.interfaces.CDCollection</remote>
<ejb-class>org.jboss.docs.cmp.cd.bean.CDCollectionBean</ejb-class>
<session-type>Stateless</session-type>
<transaction-type>Container</transaction-type>
<ejb-ref>
<ejb-ref-name>ejb/CD</ejb-ref-name>
<ejb-ref-type>Entity</ejb-ref-type>
<home>org.jboss.docs.cmp.cd.interfaces.CDHome</home>
<remote>org.jboss.docs.cmp.cd.interfaces.CD</remote>
<ejb-link>CDBean</ejb-link>
</ejb-ref>
</session>
</enterprise-beans>
<assembly-descriptor>
<container-transaction>
<method>
<ejb-name>CDBean</ejb-name>
<method-name>*</method-name>
</method>
<trans-attribute>Required</trans-attribute>
</container-transaction>
</assembly-descriptor>
</ejb-jar>
</pre><p>The first part of the listing above shows the section of ejb-jar.xml that
is relevant to the CD Bean. It has the
usual information about the classes that consitute the Bean, but it also
specifies the type
and name of the primary key, and the fields that are persistent. Note that in
this case the
"id" field gets listed twice: once as a persistent field and then again as the
primary key field.
It might be thought that specifying a field as a primary key would
automatically make it persistent,
but it doesn't. </p><p>The second part of the listing is for the CDCollection session bean.
It does not require any
persistence information,
but it does require an ejb-ref section; this indicates that the CDCollection
Bean refers to CD Bean
instances. The ejb-ref section lists the type of the CD Bean, and all its
classes. </p><p>In the JBoss run-time configuration file "jboss.xml" we should specify the
JNDI names of the
Beans, like this:</p><pre class="programlisting">
<?xml version="1.0" encoding="UTF-8"?>
<jboss>
<secure>false</secure>
<container-configurations />
<resource-managers />
<enterprise-beans>
<session>
<ejb-name>CDCollectionBean</ejb-name>
<jndi-name>cd/CDCollection</jndi-name>
<configuration-name></configuration-name>
</session>
<entity>
<ejb-name>CDBean</ejb-name>
<jndi-name>cd/CD</jndi-name>
<configuration-name></configuration-name>
</entity>
</enterprise-beans>
</jboss>
</pre><p>This says the "CDBean" has the JNDI name "cd/CD" and "CDCollectionBean" has
the JNDI name "cd/CDCollection". </p><p>To compile and package the EJBs, run "ant cmp-cd-compile". It compiles the sources
and create an EJB jar file ready for deployment.</p><p>During deployment (simply copy "documentation-example/build-examples/cmp-cd/ejb/cd.jar" to the
"deploy" subdirectory
of the JBoss directory) you should see a message like the following:</p><pre class="programlisting">
<tt>
[Default] JBoss 2.2.2 Started in 0m:5s
[Auto deploy] Auto deploy of file:/C:/Projects/jbosscvs22/jboss/dist/deploy/cd.jar
[J2EE Deployer Default] Deploy J2EE application: file:/C:/Projects/jbosscvs22/jboss/dist/deploy/cd.jar
[J2EE Deployer Default] Create application cd.jar
[J2EE Deployer Default] install module cd.jar
[Container factory] Deploying:file:/C:/Projects/jbosscvs22/jboss/dist/tmp/deploy/Default/cd.jar
[Verifier] Verifying file:/C:/Projects/jbosscvs22/jboss/dist/tmp/deploy/Default/cd.jar/ejb1001.jar
[Container factory] Deploying CDBean
[Container factory] Deploying CDCollectionBean
[JAWS] Created table 'CDBean' successfully.
[Bean Cache] Cache policy scheduler started
[Container factory] Deployed application: file:/C:/Projects/jbosscvs22/jboss/dist/tmp/deploy/Default/cd.jar
[J2EE Deployer Default] J2EE application: file:/C:/Projects/jbosscvs22/jboss/dist/deploy/cd.jar is deployed.
</tt>
</pre><p>"JAWS" is the JBoss interface to the database engine. During deployment JAWS
has
deleted any existing table called "CDBean", then created a new CDBean table
with
the specified column layout. How does it know to use VARCHAR(256) for each
field?
It doesn't: it's guessing because we haven't provided any other information.
During deployment, JAWS looks for a file called "jaws.xml"; if this file
exists
it is read to configure the names and geometry of the database tables.
VARCHAR(256) is the default for String attributes. The default table name is
the
same as that of the Bean class, which is why we have ended up with a table
called
"CDBean". This also can be over-ridden in jaws.xml. In practice, the JAWS
defaults
are adequate during developement. However, there may be speed advantages to
using fixed-length fields (e.g., CHAR(XX) rather than variable-length ones if
at
all possible.</p><p>Note that it can be very difficult to change the number or names of columns
in the table once there is data in it. JBoss gets very confused by this, as
you
would expect. When a CMP Bean is re-deployed, JAWS tries to write into its
table
all the data it had in its last deployment. If the table has different columns
it probably won't be able to do that. This means that it is important to get
the
persistent fields thoroughly correct before starting to put real data into the
application.</p></div><table border="0" cellpadding="0" cellspacing="0" height="65"><tr height="65"><td rowspan="2"><img src="gbar.gif" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/gbar.gif" width="432" height="79"></td><td rowspan="2" background="gbar.gif" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/gbar.gif" width="100%" align="right" valign="top"><a href="index.html" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/index.html"><img src="doc.gif" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/doc.gif" border="0"></a><a href="ch05.html" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/ch05.html"><img src="toc.gif" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/toc.gif" border="0"></a><a href="ch05s08.html" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/ch05s08.html"><img src="prev.gif" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/prev.gif" border="0"></a><a href="ch05s10.html" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/ch05s10.html"><img src="next.gif" tppabs="http://www.huihoo.org/jboss/online_manual/3.0/next.gif" border="0"></a></td></tr><tr></tr></table></body></html>⌨️ 快捷键说明
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