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<TITLE>Getting and Setting Initialization Parameters for a Servlet (Java Developers Almanac Example)
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<META CONTENT="Patrick Chan" NAME="AUTHOR">
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<B><A HREF="../javax.servlet/pkg.html">javax.servlet</A></B><font color="#666666" class="xsmall-font">
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<h3>e1036. Getting and Setting Initialization Parameters for a Servlet</h3>
The servlet container supports the ability to store startup and
configuration information for a servlet. After the container
instantiates the servlet, it makes this information available to the
servlet instance. This example demonstrates a servlet that retrieves
some initialization parameters in its <code>init()</code> method:
<pre> // See also <a href="../javax.servlet/com_mycompany_MyServlet.html" class="eglink"><b>e1035</b> The Quintessential Servlet</a>
// This method is called by the servlet container just before this servlet
// is put into service.
public void init() throws ServletException {
getServletContext().log("getinit init");
// Get the value of an initialization parameter
String value = getServletConfig().getInitParameter(<font color="#0066ff"><i>"param1"</i></font>);
// Get all available intialization parameters
java.util.Enumeration enum = getServletConfig().getInitParameterNames();
for (; enum.hasMoreElements(); ) {
// Get the name of the init parameter
String name = (String)enum.nextElement();
// Get the value of the init parameter
value = getServletConfig().getInitParameter(name);
}
// The int parameters can also be retrieved using the servlet context
value = getServletContext().getInitParameter(<font color="#0066ff"><i>"param1"</i></font>);
}
</pre>
The initialization parameters for the servlet are specified in the
deployment descriptor (i.e., web.xml file). Here is an example of a
deployment descriptor that specifies two initialization parameters:
<pre> <web-app>
<servlet>
<servlet-name><font color="#0066ff"><i>MyServletName</i></font></servlet-name>
<servlet-class><font color="#0066ff"><i>com.mycompany.MyServlet</i></font></servlet-class>
<init-param>
<param-name> <font color="#0066ff"><i>param1</i></font> </param-name>
<param-value> <font color="#0066ff"><i>value1</i></font> </param-value>
</init-param>
<init-param>
<param-name> <font color="#0066ff"><i>param2</i></font> </param-name>
<param-value> <font color="#0066ff"><i>value2</i></font> </param-value>
</init-param>
...
</servlet>
...
</web-app>
</pre>
Note that the leading and trailing space around the parameter value is
trimmed.
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<b>Related Examples</b></font></td>
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e1035. <a class="eglink" href="com_mycompany_MyServlet.html?l=rel">
The Quintessential Servlet
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e1037. <a class="eglink" href="GetImage.html?l=rel">
Returning an Image in a Servlet
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e1038. <a class="eglink" href="State.html?l=rel">
Saving Data in a Servlet
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<br>
e1039. <a class="eglink" href="Log.html?l=rel">
Logging a Message in a Servlet
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