11. Servlet Init parameters and ServletConfig interface

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Servlet Init parameters and ServletConfig interface

Init parameters:

Init parameters refers to the initialization parameters of a servlet or filter. attribute is used to define a init parameter. attribute has two main sub attributes and . The contains the name of the parameter and contains the value of the parameter.

ServletConfig interface:

ServletConfig interface is used to access the init parameters.

Methods of ServletConfig interface:

1. getInitParameter(String name): Returns the value of the specified parameter if parameter exist otherwise return null.
Syntax: public String getInitParameter(String name)
2. getInitParameterNames(): Returns the names of init parameters as Enumeration if servlet has init parameters otherwise returns an empty Enumeration.
Syntax: public Enumeration getInitParameterNames()
3. getServletContext():Returns an instance of ServletContext.
Syntax: public ServletContext getServletContext()
4. getServletName():Returns the name of the servlet.
Syntax: public String getServletName()


import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 * This class is used to show the use of init parameters.
 * @author javatutorialpoint
public class InitParamExample extends HttpServlet {
 private static final long serialVersionUID = 1L;
        //no-argument constructor
        public InitParamExample() {
      protected void doGet(HttpServletRequest request, 
  HttpServletResponse response)
           throws ServletException, IOException {
     PrintWriter out = response.getWriter();
     //get ServletConfig object.
     ServletConfig config=getServletConfig(); 
     //get init parameter from ServletConfig object.
     String appUser = config.getInitParameter("appUser");

Application User: "

+ appUser + "
");   out.close(); } }
xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
id="WebApp_ID" version="2.5">


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