Here’s a serlvet code example to demonstrate how to pass a parameter to a servlet by using ServletConfig “init-param” in web.xml
In the deployment descriptor (web.xml)
Put your parameter value in “init-param” and make sure inside the “servlet” element
<servlet>
<servlet-name>ServletName</servlet-name>
<servlet-class>com.mkyong.ServletDemo</servlet-class>
<init-param>
<param-name>email</param-name>
<param-value>[email protected]</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>ServletName</servlet-name>
<url-pattern>/Demo</url-pattern>
</servlet-mapping>
Servlet code
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException{
PrintWriter pw = response.getWriter();
pw.println(getServletConfig().getInitParameter("email"));
}
The “getServletConfig().getInitParameter(“email”)” method is use to get the ServletConfig parameter value in web.xml. Btw, this parameter only available for this servlet only. If you want a parameter which allow globally access by whole web application, you need put the parameter in servlet context element.
Here’s an example to pass parameter to whole web application.
how to change value of servlet config parameter at runtime.
Is it possible to extend the above servlet and then to access the init-parameter in the extended servlet.
Like we could create a global variable and save the servletConfig object then to access the variable in the extended servlet.