Get all Request Parameters in Servlet

Byron KiourtzoglouNovember 11th, 2012Last Updated: March 7th, 2019

3 6,224 1 minute read

With this tutorial we shall show you how to get all requests parameters in a Java Servlet. This the most basic step you have to consider when developing a Servelt application because HTTP is based mostly on parameters exchange.

Basically in order to get all Request Parameters in Servlet, one should take the following steps:

Create a handleRequest method so you can use it both in doGet and doPost methods.
Use HttpServletRequest.getParameterNames to get an Enumeration of parameter names.
Use HttpServletRequest.getParameterValues(paramName) to get the parameters values.

Let’s see the simple code snippets that follow:

package com.javacodegeeks.snippets.enterprise;
 
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;
 
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
public class GetAllRequestParametersInServlet extends HttpServlet {
 
    private static final long serialVersionUID = -2128122335811219481L;
 
    public void doGet(HttpServletRequest req, HttpServletResponse res) throws IOException {
        handleRequest(req, res);
    }
 
    public void doPost(HttpServletRequest req, HttpServletResponse res) throws IOException {
        handleRequest(req, res);
    }
 
    public void handleRequest(HttpServletRequest req, HttpServletResponse res) throws IOException {
 
        PrintWriter out = res.getWriter();
        res.setContentType("text/plain");
 
        Enumeration<String> parameterNames = req.getParameterNames();
 
        while (parameterNames.hasMoreElements()) {
 
            String paramName = parameterNames.nextElement();
            out.write(paramName);
            out.write("n");
 
            String[] paramValues = req.getParameterValues(paramName);
            for (int i = 0; i < paramValues.length; i++) {
                String paramValue = paramValues[i];
                out.write("t" + paramValue);
                out.write("n");
            }
 
        }
 
        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.GetAllRequestParametersInServlet</servlet-class>
    </servlet>
 
    <servlet-mapping>
        <servlet-name>JCG Snippets Application</servlet-name>
        <url-pattern>/jcgservlet</url-pattern>
    </servlet-mapping>
 
</web-app>

URL:

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http://myhost:8080/jcgsnippets/jcgservlet?param1=paramvalue1&param2=paramvalue2a&param2=paramvalue2b

Output:

param2
	paramvalue2a
	paramvalue2b
param1
	paramvalue1

This was an example on how to get all Request Parameters in Servlet.

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Get all Request Parameters in Servlet

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