The following sections describe how to configure Web application resources.
The resources that you use in a Web application are generally deployed externally to the Web application. JDBC DataSources can optionally be deployed within the scope of the Web application as part of an EAR file.
To use external resources in the Web application, you resolve the JNDI resource name that the application uses with the global JNDI resource name using the
weblogic.xml deployment descriptors. (The
web.xml file is located in the
WEB-INF directory of your Web application.) See for more information.
You can also deploy JDBC DataSources as part of the Web application EAR file by configuring those resources in the weblogic-application.xml deployment descriptor. Resources deployed as part of the EAR file with scope defined as application are referred to as application-scoped resources. These resources remain private to the application, and application components can access the resource names by adding
<resource-ref> as explained in Configuring Resources.
When accessing resources such as a DataSource from a Web application through Java Naming and Directory Interface (JNDI), you can map the JNDI name you look up in your code to the actual JNDI name as bound in the global JNDI tree. This mapping is made using both the
weblogic.xml deployment descriptors and allows you to change these resources without changing your application code. You provide a name that is used in your Java code, the name of the resource as bound in the JNDI tree, and the Java type of the resource, and you indicate whether security for the resource is handled programmatically by the servlet or from the credentials associated with the HTTP request. You can also access JMS module resources, such as queues, topics, and connection factories. For more information see, Configuring JMS Application Modules for Deployment in Configuring and Managing WebLogic JMS.
To configure resources:
The following example illustrates how to use an external DataSource. It assumes that you have defined a data source called
accountDataSource. For more information, see JDBC Data Sources Online Help.
javax.sql.DataSource ds = (javax.sql.DataSource) ctx.lookup
. . .
. . .
Web applications can access EJBs that are deployed as part of a different application (a different EAR file) by using an external reference. The EJB being referenced exports a name to the global JNDI tree in its
weblogic-ejb-jar.xml deployment descriptor. An EJB reference in the Web application module can be linked to this global JNDI name by adding an
ejb-reference-description element to its
weblogic.xml deployment descriptor.
This procedure provides a level of indirection between the Web application and an EJB and is useful if you are using third-party EJBs or Web applications and cannot modify the code to directly call an EJB. In most situations, you can call the EJB directly without using this indirection. For more information, see Programming WebLogic Enterprise JavaBeans.
To reference an external EJB for use in a Web application:
ejb-refelement of the J2EE standard deployment descriptor, web.xml. (The
web.xmlfile is located in the
WEB-INFdirectory of your Web application.)
ejb-reference-descriptionelement of the WebLogic-specific deployment descriptor,
weblogic.xml, to the JNDI name defined in the
If the Web application is part of an Enterprise Application Archive (EAR file), you can reference an EJB by the name used in the EAR with the
ejb-link element of the J2EE standard deployment descriptor, web.xml.
The ejb-ref element in the web.xml deployment descriptor declares that either a servlet or JSP is going to be using a particular EJB. The ejb-reference-description element in the weblogic.xml deployment descriptor binds that reference to an EJB, which is advertised in the global JNDI tree.
The ejb-reference-descriptor element indicates which ejb-ref element it is resolving with the ejb-ref-name element. That is, the ejb-reference-descriptor and ejb-ref elements with the same ejb-ref-name element go together.
With the addition of the ejb-link syntax, the ejb-reference-descriptor element is no longer required if the EJB being used is in the same application as the servlet or JSP that is using the EJB.
The ejb-ref-name element serves two purposes in the web.xml deployment descriptor:
Context ctx = new InitialContext();
ctx = (Context)ctx.lookup("java:comp/env");
Object o = ctx.lookup("ejb1");
Ejb1Home home = (Ejb1Home) PortableRemoteObject.narrow(o, Ejb1Home.class);
Within an application, WebLogic Server binds any EJBs referenced by other application components to the environments associated with those referencing components. These resources are accessed at runtime through a JNDI name lookup relative to java:comp/env.
The following is an example of an application deployment descriptor (application.xml) for an application containing an EJB and a Web application, also called an Enterprise Application. (For the sake of brevity, the XML header is not included in this example.)
To allow the code in the Web application to use an EJB in ejb1.jar, the J2EE standard Web application deployment descriptor, web.xml, must include an ejb-ref stanza that contains an ejb-link referencing the JAR file and the name of the EJB that is being called.
The format of the ejb-link entry must be as follows:
where filename is the name of the JAR file, relative to the Web application, and ejbname is the EJB within that JAR file. The ejb-link element should look like the following:
Note that since the JAR path is relative to the WAR file, it begins with "../". Also, if the ejbname is unique across the application, the JAR path may be dropped. As a result, your entry may look like the following:
The ejb-link element is a sub-element of an ejb-ref element contained in the Web application's web.xml descriptor. The ejb-ref element should look like the following:
Referring to the syntax for the ejb-link element in the above example,
the portion of the syntax to the left of the # is a relative path to the EJB module being referenced. The syntax to the right of # is the particular EJB being referenced in that module. In the above example, the EJB JAR and WAR files are at the same level.
The name referenced in the ejb-link (in this example, myejb) corresponds to the ejb-name element of the referenced EJB's descriptor. As a result, the deployment descriptor (ejb-jar.xml) of the EJB module that this ejb-ref element is referencing should have an entry similar to the following:
Notice the ejb-name element is set to myejb.
At runtime, the Web application code looks up the EJB's JNDI name relative to java:/comp/env. The following is an example of the servlet code:
MyHome home = (MyHome)ctx.lookup("java:/comp/env/ejb1");
The name used in this example (ejb1) is the ejb-ref-name defined in the ejb-ref element of the web.xml segment above.
If you need to serve classes or other resources from the system
CLASSPATH, or from the
WEB-INF/classes directory of a Web application, you can use a special servlet called the
ClasspathServlet is useful for applications that use applets or RMI clients and require access to server-side classes. The
ClasspathServlet is implicitly registered and available from any application.
ClasspathServlet is always enabled by default. To disable it, set the ServerMBean parameter ClassPathServletDisabled to true (default = false).
ClasspathServlet returns the classes or resources from the system
CLASSPATH in the following order:
To serve a resource from the
WEB-INF/classes directory of a Web application, call the resource with a URL such as:
In this case, the resource is located in the following directory, relative to the root of the Web application:
|Note:||WebLogic Server provides functionality to support your legacy Common Gateway Interface (CGI) scripts. For new projects, we suggest you use HTTP servlets or JavaServer Pages.|
WebLogic Server supports all CGI scripts through an internal WebLogic servlet called the
CGIServlet. To use CGI, register the
CGIServlet in the Web application deployment descriptor. See .
To configure CGI in WebLogic Server:
CGIServletin your Web application by using the
servlet-mappingelements in the J2EE standard Web application deployment descriptor,
web.xmlfile is located in the
WEB-INFdirectory of your Web application.) The class name for the
weblogic.servlet.CGIServlet. You do not need to package this class in your Web application.
CGIServletby defining the following
;” (Windows) or a “
:” (UNIX). If you do not specify cgiDir, the directory defaults to a directory named cgi-bin under the Web application root.
param-namefor extension mappings must begin with an asterisk followed by a dot, followed by the file extension, for example,
param-valuecontains the path to the interpreter or executable that runs the script. You can create multiple mappings by creating a separate
init-paramelement for each mapping.
The URL used to request a Perl script must follow the pattern:
For a list of CGI Best Practices, see CGI Best Practices.