java servlet are executed when user request for some resource in server. ServletConfig is interface defined in javax.servlet package. ServletConfig is used to access servlet’s initial value stored in web.xml. For each servlet there is one ServletConfig.
Initial value for servlet are stored in web.xml with name value pair as follows
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | <servlet> <servlet-name>ServletName</servlet-name> <servlet-class>ServletClass</servlet-class> <init-param> <param-name>Param1</param-name> <param-value>Value1</param-value> </init-param> <init-param> <param-name>Param2</param-name> <param-value>Value2</param-value> </init-param> ....... </servlet> <servlet-mapping> <servlet-name>ServletName</servlet-name> <url-pattern>/url-pattern</url-pattern> </servlet-mapping> |
initial parameter are specified inside <servlet> tag as specified above.
A servlet can have one or more <init-param></init-param> tags to store initial values
index.html
1 2 3 4 5 6 7 8 9 10 11 | <html> <head> <title>Servlet Config Example</title> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> </head> <body> <h1>Servlet Config Example</h1> <a href="get-config">Call Servlet</a> </body> </html> |
web.xml
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | <?xml version="1.0" encoding="UTF-8"?> <web-app version="3.1" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"> <servlet> <servlet-name>ServletConfig</servlet-name> <servlet-class>ebhor.servlet.ServletConfig</servlet-class> <init-param> <param-name>PaymentMode</param-name> <param-value>Online</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>ServletConfig</servlet-name> <url-pattern>/get-config</url-pattern> </servlet-mapping> <session-config> <session-timeout> 30 </session-timeout> </session-config> </web-app> |
ServletConfig.java
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | package ebhor.servlet; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class ServletConfig extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out=response.getWriter(); String paymentMode=getServletConfig().getInitParameter("PaymentMode"); out.println("<h2>Our Payment mode is "+paymentMode+"</h2>"); } } |
Result
