How do I check if parameter is exists in servlet request?
Category: javax.servlet, viewed: 4442 time(s).
ServletRequest object has a map object that maps parameter name and its value. By accessing this map we can check if a parameter was passed in servlet request. Let's see the example below.
package org.kodejava.example.servlet;
import java.io.IOException;
import javax.servlet.Servlet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ParameterCheck extends HttpServlet implements Servlet {
private static final String EMPTY = "";
public ParameterCheck() {
super();
}
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
String username = EMPTY;
String password = EMPTY;
//
// Check if username parameter exists
//
if (request.getParameterMap().containsKey("username")) {
username = request.getParameter("username");
}
//
// Check if password parameter exists
//
if (request.getParameterMap().containsKey("password")) {
password = request.getParameter("password");
}
}
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
}
}
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