Java ajax passing values from jsp to servlet
Question
I am trying to pass basic values such as id from jsp to the servlet through ajax. I tried everything but only null is being passed. Even console.log(val) does not print anything to browser console.
My understanding is: Web page has form values which onsubmit calls js file. js has ajax which calls the servlet and passes the data of the form. The servlet grabs data from ajax by request.getParameter(val)
Here is my code:
Main.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js" type="text/javascript">
<script src="js/main.js" type="text/javascript"></script>
</head>
<body>
<form method="post" action="Main" id="firstform">
<h1>Enter name:</h1>
<input type="text" name="id" id="id" />
<input type="submit" name="submit"/>
</form>
</body>
</html>
main.js
var form = $('#firstform');
console.log("gi");
form.submit(function()
{
$.ajax({
url: 'Main',
data: form.serialize(),
type: 'post',
success: function(data){
console.log(data);
}
});
//return false;
});
Main.java
package servlets;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class Main
*/
@WebServlet("/Main")
public class Main extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public Main() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
int ids;
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
String val = request.getParameter("id");
System.out.print(val);
if(val != null){
ids = Integer.parseInt(val);
out.print(ids); //
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}
}
**Problems:
1)values passed from jsp to servlet
2)console.log doesnt print anything on browser console
1) works but 2) still doesnt.**
3 answers
solution1
4 ACCPTED 2014-05-06 04:24:24
在main.js类型中是type: 'post' ，你在get方法中编写代码做type:'get'
solution2
3 2014-05-06 04:30:22
there is no name attribute in your input field. when you are doing
String val = request.getParameter("id");
then in servlet then it will search for the input field having name="id" but in your form there is nothing so it will return null ;
give name to the input field like
<input type="text" id="id" name="id"/>
also as sanjay has said your ajax has type post so change it to get as well
solution3
0 2014-05-17 15:02:25
Just for the console.log(data) problem, may be $.ajax() function get confused with response type, try this:
Ajax
$.ajax({ url: 'Main', data: form.serialize(), type: 'post', dataType:'text/plain', success: function(data){ console.log(data); } });Servlet
response.setContentType("text/plain;charset=UTF-8");
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