Get/Set init Parameters in Servlet (original) (raw)

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

<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>

URL:

http://myhost:8080/jcgsnippets/jcgservlet

Output:

myparam = myvalue

This was an example on how to get/set init Parameters in Servlet.

Ilias is a software developer turned online entrepreneur. He is co-founder and Executive Editor at Java Code Geeks.