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:
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
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 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/jcgservletOutput:
myparam = myvalueThis was an example on how to get/set init Parameters in Servlet.
