java - How can I make my website communicate with my servlet? -

i've created web app gets jqtree "coordinates" , send these coordinates var positions server gotten servlet create file containing "coordinates", however, i don't know how going make communication. me?

thanks in advance.

i made kind of chart right below explaining idea.

1 - user changes tree

2 - positions gotten code

$(document).ready(function() {  var positions;  //var data dynamic json file should created in backend. var data = [{     label: 'node1',     id: 1,     children: [{         label: 'child1',         id: 2     }, {         label: 'child2',         id: 3     }] }, {     label: 'node2',     id: 4,     children: [{         label: 'child3',         id: 5     }] }]; $('#tree1').tree({     data: data,     autoopen: true,     draganddrop: true });   console.log($('#tree1').tree('tojson')); //this give loading jqtree structure.  $('#tree1').bind(     'tree.move',     function(event) {         event.preventdefault();         // move first, , _then_ post back.         event.move_info.do_move();         console.log($(this).tree('tojson')); //this give latest tree.         positions = $(this).tree('tojson');         alert(positions);         $.post('http://myserver', {             tree: $(this).tree('tojson')         });         alert("done"); //this post json of latest tree structure.     } );   }); 

3 - should sent ajax

$(function() { alert("file has been sent"); var data = new formdata(); data.append("custom_css", positions); $.ajax({     url: 'myserver',     type: 'post',     data: data,     cache: false,     datatype: 'json',     processdata: false,     contenttype: false,     success: function(response) {         alert("file has been sent");     },     error: function(jqxhr, textstatus, errorthrown) {         alert('errors: ' + textstatus);     } });  }); 

4 - , received servlet , saved text file: positions.txt

package com.srccodes.example;  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 helloworld */ @webservlet("/helloworld") public class helloworld extends httpservlet {     private static final long serialversionuid = 1l;  /**  * @see httpservlet#httpservlet()  */ public helloworld() {     super();     // todo auto-generated constructor stub }  /**  * @see httpservlet#doget(httpservletrequest request, httpservletresponse response)  */ protected void doget(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {     response.setcontenttype("text/html");     printwriter printwriter  = response.getwriter();     printwriter.println("<h1>hello world!</h1>");      string position = "jqtree positions";     printwriter writer = new printwriter("positions.txt", "utf-8");     writer.println(position);     writer.close(); }  /**  * @see httpservlet#dopost(httpservletrequest request, httpservletresponse response)  */ protected void dopost(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {     // todo auto-generated method stub }  } 

1. your .ajax url should match @webservlet() mapping. in case "/helloworld"
2. since posting data, should override dopost() method in servlet.
3. finally in dopost() method, retrieve data "custom_css" variable .. request.getparameter("custom_css")
4. proceed rest of business logic.

---

---

$.ajax({     url: '/helloworld',     type: 'post',     data: data,     cache: false, 

---

protected void dopost(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {     request.getparameter("custom_css")  // proceed business logic here, using above data // // // // }