properties file in a jar for EJB 3.0

[RVic]

I have an EJB 3.0 that I need to parameterize with a properties file.
Where do I put this file in the directory structure within the jar,
and how do I access it? Thanks RVic

 

[jlp]

RVic a écrit :

I have an EJB 3.0 that I need to parameterize with a properties file.
Where do I put this file in the directory structure within the jar,
and how do I access it? Thanks RVic

Look at ClassLoader.getResourceAsStream(String resource).

 

[RVic]

But where does it go in the directory structure? If I have a file
called myproperties.properties, do I put it in /MANIFEST-INF? Do I put
it at the top level dir in the jar?

 

[Giovanni Azua]

Hello RVic,

In short, you shouldn't access files specially not for the purpose of
configuration. This is explicitly discouraged/forbidden in the EJB3-spec
[1].



See the

 

[Giovanni Azua]

Hello RVic,

Please ignore my previous post, by mistake I pressed the wrong key
combination.

I have an EJB 3.0 that I need to parameterize with a properties file.
Where do I put this file in the directory structure within the jar,
and how do I access it? Thanks RVic

In short, you shouldn't access files specially not for the purpose of
configuration. This is explicitly discouraged/forbidden in the EJB3-spec
[1 p545].

"
.. An enterprise bean must not use the java.io package to attempt to access
files and directories in the file system.

The file system APIs are not well-suited for business components to access
data. Business components should use a resource manager API, such as JDBC,
to store data."

You should instead use <env-entry> and get the values injected using
@Resource.

HTH,
Best regards,
Giovanni

[1] JSR-000220 Enterprise JavaBeans 3.0 Final Release (ejbcore)
<http://jcp.org/aboutJava/communityprocess/final/jsr220/index.html>

 

[Lew]

Look at ClassLoader.getResourceAsStream(String resource).

or Class.getResourceAsStream( String resource )

But where does it go in the directory structure? If I have a file
called myproperties.properties, do I put it in /MANIFEST-INF? Do I put
it at the top level dir in the jar?

Talk a look at the Javadocs for getResourceAsStream(). You put the
resource in the classpath, i.e., in the same directory tree where
'.class' files go inside the JAR. An abslolute path in the argument
to getResourceAsStream() corresponds to a path relative to a classpath
entry.

See the rules for path resolution at
<http://java.sun.com/javase/6/docs/api/java/lang/Class.html#getResource
(java.lang.String)>

Bear in mind we are reading from the class path for the application,
i.e., paths inside the JAR, not the file system overall.

JAYF - Javadocs are your friend. Be in the habit of reading them.

 

[RVic]

Giovanni,

Ok, but what file do I find <env-entry> in? Is it in an xml file in
MANIFEST-INF? Or is it in an xml file I put in my deploy directory
(Using JBoss 5.1, ejb 3.0) Thank you so much. RVic

 

[Giovanni Azua]

Hi RVic,

Ok, but what file do I find <env-entry> in? Is it in an xml file in
MANIFEST-INF? Or is it in an xml file I put in my deploy directory
(Using JBoss 5.1, ejb 3.0) Thank you so much. RVic

You place env-entry constants in:
META-INF/ejb-jar.xml

"The ejb-jar file must contain the deployment descriptor (if any) in the
format defined in Chapter 19. The
deployment descriptor must be stored with the name META-INF/ejb-jar.xml in
the ejb-jar file." [1, p540]

See an example of ejb-jar.xml below taken from that same spec [1, p411] and
the configurable attributes declared as [1, p412]:

// The maximum number of tax exemptions, configured by the Deployer.
@Resource int maxExemptions = 4; // defaults to 4

Another interesting reason to avoid reading even from the same ejb jar [1,
p546]:

"The enterprise bean must not attempt to directly read or write a file
descriptor.
Allowing the enterprise bean to read and write file descriptors directly
could compromise security."

HTH,
Best regards,
Giovanni

<?xml version = '1.0' encoding = 'windows-1252'?>
<ejb-jar version="3.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/ejb-jar_3_0.xsd">
<enterprise-beans>
<session>
...
<ejb-name>EmployeeService</ejb-name>
<ejb-class>com.wombat.empl.EmployeeServiceBean</ejb-class>
...
<env-entry>
<description>
The maximum number of tax exemptions
allowed to be set.
</description>
<env-entry-name>maxExemptions</env-entry-name>
<env-entry-type>java.lang.Integer</env-entry-type>
<env-entry-value>15</env-entry-value>
</env-entry>
<env-entry>
<description>
The minimum number of tax exemptions
allowed to be set.
</description>
<env-entry-name>minExemptions</env-entry-name>
<env-entry-type>java.lang.Integer</env-entry-type>
<env-entry-value>1</env-entry-value>
</env-entry>
<env-entry>
<env-entry-name>foo/name1</env-entry-name>
<env-entry-type>java.lang.String</env-entry-type>
<env-entry-value>value1</env-entry-value>
</env-entry>
<env-entry>
<env-entry-name>foo/bar/name2</env-entry-name>
<env-entry-type>java.lang.Boolean</env-entry-type>
<env-entry-value>true</env-entry-value>
</env-entry>
<env-entry>
<description>Some description.</description>
<env-entry-name>name3</env-entry-name>
<env-entry-type>java.lang.Integer</env-entry-type>
</env-entry>
<env-entry>
<env-entry-name>foo/name4</env-entry-name>
<env-entry-type>java.lang.Integer</env-entry-type>
<env-entry-value>10</env-entry-value>
</env-entry>
...
</session>
</enterprise-beans>
<interceptors/>
<assembly-descriptor/>
</ejb-jar>

 

[RVic]

Giovanni,

Thank you. I need this not for a session bean, but for an mbean. In
my /META-INF I have presently 2 xml files, a persistence.xml, and a
jboss-service.xml, as shown below. Should I create a seperate xml file
for these parameters? They will be used by the mbean itself that I am
setting up in jbos-service.xml. -RVic

<?xml version="1.0" encoding="UTF-8"?>
<server>
<mbean code="com.s.listener.SocketService"
name="com.s:service=PortBinding">
<depends>jboss.j2ee:jar=s-trans-
server.jar,name=DispatchHandlerBean,service=EJB3</depends>
<attribute name="Message">Port Listening</attribute>
<!-- NOTE: sys admin's should configure listening ports here -->
<attribute name="Port">20001</attribute>
<attribute name="Port7e1">20002</attribute>
</mbean>
</server>

 

[Giovanni Azua]

Thank you. I need this not for a session bean, but for an mbean. In
my /META-INF I have presently 2 xml files, a persistence.xml, and a
jboss-service.xml, as shown below. Should I create a seperate xml file

yes in the ejb-jar.xml

<mbean code="com.s.listener.SocketService"

)) yet another violation of the ejb spec! [sigh]

"An enterprise bean must not attempt to listen on a socket, accept
connections on a socket, or
use a socket for multicast.
The EJB architecture allows an enterprise bean instance to be a network
socket client, but it does not
allow it to be a network server. Allowing the instance to become a network
server would conflict with
the basic function of the enterprise bean- to serve the EJB clients." [1,
p545]

 

[Arne Vajhøj]

I have an EJB 3.0 that I need to parameterize with a properties file.
Where do I put this file in the directory structure within the jar,
and how do I access it? Thanks RVic

In short, you shouldn't access files specially not for the purpose of
configuration. This is explicitly discouraged/forbidden in the EJB3-spec
[1 p545].

"
. An enterprise bean must not use the java.io package to attempt to access
files and directories in the file system.

That does not prohibit reading properties as a resource
within the jar file.

Arne

 

[Arne Vajhøj]

But where does it go in the directory structure? If I have a file
called myproperties.properties, do I put it in /MANIFEST-INF? Do I put
it at the top level dir in the jar?

Anywhere.

You just open it with the path it has in the jar file.

Arne

 

[Lew]

Ok, but what file do I find <env-entry> in? Is it in an xml file in
MANIFEST-INF? Or is it in an xml file I put in my deploy directory
(Using JBoss 5.1, ejb 3.0)

<http://java.sun.com/javaee/6/docs/tutorial/doc/bnblr.html>
<http://java.sun.com/javaee/6/docs/tutorial/doc/bncjh.html>
<http://java.sun.com/javaee/6/docs/tutorial/doc/bncjk.html>
<http://java.sun.com/developer/EJTechTips/txtarchive/2003/Dec03_MarkJ.txt>

 

[RVic]

Thanks Guys,

I just realized.....it isn;t getting put into my jar file because I
don;t have that specified in my Ant script. I;ve been operating the
past few hours assuming, because it is in my project's filesystem,
that it was also in the jar. Duh! Yes, now I can access it. Thanks so
much guys.

As for using resource injection, I have a need for that too with the
same bean. However, I am not sure in the ejb-jar.xml how to specify
the onw tag for it:
<enterprise-beans>
<session>
....

Because this is NOT a session bean, it is a message bean. Would I
therefore put this as:
<enterprise-beans>
<message>

? Thanks again.

 

[Arne Vajhøj]

I just realized.....it isn;t getting put into my jar file because I
don;t have that specified in my Ant script. I;ve been operating the
past few hours assuming, because it is in my project's filesystem,
that it was also in the jar. Duh! Yes, now I can access it.

The small details ...

Arne