Monday, 25 November 2013

Send POST Request to Servlet in JQuery in One Statement!

Post request with JQuery
Here is a single-line statement to send a POST request to a servlet with JQuery. This is gonna be dead simple. Yes, so simple that it is nothing more than a JQuery method call. Curious about what the method is? Me too! It is none other than..

post(): There are a lot of versions of this method. But here, we are going to use the simple version which takes the url-pattern and the data to be submitted.

Project structure

Folder: D:\Program Files\Apache Software Foundation\Tomcat 8.0\webapps\jq_post


jq_post
        |
        +-- index.html
        +-- WEB-INF
                    +-- classes
                            +-- simple.java
                            +-- simple.class

index.html


<html>
    <head>
        <title>Send POST Request to Servlet with JQuery</title>
        <script src="http://code.jquery.com/jquery-2.0.0.js"></script>
        <script>
            $(function(){
           
            $( "#hform" ).submit(function(event) {
           
                // Stop form from submitting normally
                event.preventDefault();
               
                // Get some values from elements on the page:
                var form = $(this);
               
                // Get the value in input uname
                term=$("input[name='uname']").val();
               
                // Send the data using post
                var posting = $.post("hello",{uname:term});
               
                    // When the POST request is done..
                    // data: The output printed in servlet
                    posting.done(function(data) {
                       
                        // Put the results in a div
                        $("#view").append(data+"<br/>");
                       
                    });
            });
            });
        </script>
    </head>
   
    <body>
   
        <!--Create the form-->
        <form id="hform" action="/jq_post/hello" method="post">
            <input type="text" name="uname"/>
            <input type="submit" value="SUBMIT"/>
        </form>
        <!--Create the form-->
       
        <div id="view"/>
    </body>
   
</html>

web.xml - Deployment descriptor



<web-app>
    <servlet>
        <servlet-name>ser</servlet-name>
        <servlet-class>simple</servlet-class>
    </servlet>
   
    <servlet-mapping>
        <servlet-name>ser</servlet-name>
        <url-pattern>/hello</url-pattern>
    </servlet-mapping>
</web-app>

Related: What is web.xml in servlets?

simple.java contains doPost()



import javax.servlet.http.*;
import javax.servlet.*;
import java.io.*;
public class simple extends HttpServlet
{
    public void doPost(HttpServletRequest req,HttpServletResponse res) throws ServletException,IOException
    {
        // Get the user name from html input field
        String name=req.getParameter("uname");
       
        // Get PrintWriter obj using getWriter() in HttpServletResponse
        PrintWriter pw=res.getWriter();
       
        // Print, that's it!!
        pw.println("Hello "+name+"!");
    }
}

Image credit: tuicool.com

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