Question

ServletConfig Interface in Java

Answer 1

ServletConfig Interface

An object of ServletConfig is created by the web container for each servlet. This object can be used to get configuration information from web.xml file. If the configuration information is modified from the web.xml file, we don't need to change the servlet. So it is easier to manage the web application if any specific content is modified from time to time.

Note: The core advantage of ServletConfig is that you don't need to edit the servlet file if information is modified from the web.xml file.

Methods of ServletConfig interface

Method	Description
public String getInitParameter(String name)	Returns the parameter value for the specified parameter name
public Enumeration getInitParameterNames()	Returns an enumeration of all the initialization parameter names
public String getServletName()	Returns the name of the servlet
public ServletContext getServletContext()	Returns an object of ServletContext

Example Code

DemoServ.java

import java.io.IOException;   import java.io.PrintWriter;   import java.util.Enumeration;      import javax.servlet.ServletConfig;   import javax.servlet.ServletException;   import javax.servlet.http.HttpServlet;   import javax.servlet.http.HttpServletRequest;   import javax.servlet.http.HttpServletResponse;  public class DemoServ extends HttpServlet {   public void doGet(HttpServletRequest request, HttpServletResponse response)           throws ServletException, IOException {      response.setContentType("text/html");       PrintWriter out = response.getWriter();       ServletConfig config=getServletConfig();       Enumeration<String> e=config.getInitParameterNames();          String str="";       while(e.hasMoreElements()){       str=e.nextElement();       out.print("<br>Name: "+str);       out.print(" value: "+config.getInitParameter(str));       }              out.close();   }   }

index.html
<a href="servlet1">Click here</a>

web.xml

<?xml version="1.0"?> <web-app> <servlet> <servlet-name>DemoServ</servlet-name> <servlet-class>DemoServ</servlet-class> <init-param> <param-name>username</param-name> <param-value>system</param-value> </init-param> <init-param> <param-name>password</param-name> <param-value>oracle</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>DemoServ</servlet-name> <url-pattern>/servlet1</url-pattern> </servlet-mapping> </web-app>

Output

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