servlet
Get/Set init Parameters in Servlet
In this example we are going to see how to get/set init parameters in a Servelt. Using init parameters you can specify several important aspects of your servlets that are going to be handled during requests service.
In short, to get/set init Parameters in Servlet you should:
- Create public void init() function on your servlet.
- Call getServletConfig().getInitParameterNames()
- Use put(initParamName, initParamValue) to put parameters in your init parameter map.
- In your doGet method use initParamsMap.entrySet().iterator() to get an Iterator an iterate through init parameters.
Let’s see the code snippets that follow:
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 | package com.javacodegeeks.snippets.enterprise; 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 GetSetInitParametersInServlet extends HttpServlet { private static final long serialVersionUID = -2128122335811219481L; private String paramName; private String paramValue; public void init() throws ServletException { paramName = "myparam" ; paramValue = getServletConfig().getInitParameter(paramName); } public void doGet(HttpServletRequest req, HttpServletResponse res) throws IOException { PrintWriter out = res.getWriter(); res.setContentType( "text/plain" ); out.write(paramName); out.write( " = " ); out.write(paramValue); out.close(); } } |
web.xml
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | <? xml version = "1.0" encoding = "UTF-8" ?> xmlns = "http://java.sun.com/xml/ns/javaee" xmlns:web = "http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation = "http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version = "2.5" > < display-name >JCG Snippets Web Project</ display-name > < servlet > < servlet-name >JCG Snippets Application</ servlet-name > < servlet-class >com.javacodegeeks.snippets.enterprise.GetSetInitParametersInServlet</ servlet-class > < init-param > < param-name >myparam</ param-name > < param-value >myvalue</ param-value > </ init-param > </ servlet > < servlet-mapping > < servlet-name >JCG Snippets Application</ servlet-name > < url-pattern >/jcgservlet</ url-pattern > </ servlet-mapping > </ web-app > |
URL:
http://myhost:8080/jcgsnippets/jcgservlet
Output:
myparam = myvalue
This was an example on how to get/set init Parameters in Servlet.