How to pass parameters to whole web application – ServletContext

Here’s a serlvet code example to demonstrate how to pass a parameter to whole web application by using ServletContext “init-param” in web.xml.

In the deployment descriptor (web.xml)

Put your parameter value in “init-param” and make sure outside the “servlet” element

        <servlet>
		<servlet-name>ServletName</servlet-name>
		<servlet-class>com.mkyong.ServletDemo</servlet-class>
	</servlet>
 
	<context-param>
			<param-name>email</param-name>
			<param-value>admin@email.com</param-value>
	</context-param>

Servlet code

public void doGet(HttpServletRequest request, HttpServletResponse response)
	throws IOException{
 
		PrintWriter pw = response.getWriter();
		pw.println(getServletContext().getInitParameter("email"));
 
	}

The “getServletContext().getInitParameter(“email”)” method is use to get the ServletContext parameter value in web.xml. In addition , this parameter is accessible by the whole web application.

Here’s a example to pass parameter to a servlet only