Jquery 带有 Servlet 以获取数据库 JSON 数组 object

Question

Stackoverflow team members.

I am struggling to get the solution of my problem. Actually in my application I want to make use of Jquery and Json with Servlet. In my Application There is one JSP Servlet page to enter detail entry like user_name , user_address etc.

All this data will be send to database using jquery ajax. Now I want to retrieve all records that are inserted to database using json in the form of json array object.

I am able to insert record to database but I don't know how to get them back from database to json object array so i can use them again. in some another jsp servlet page.

Help me solve my problem.

Best Regards
Yogendra

Answer 1

First of all you need to do an Ajax call to your servlet, see following code:

    $.getJSON("yourServlet", function(json) {
    alert("JSON Received Data: " + json);
    //Logic to Parse the received JSON
    });
   </script>

Secondly construct JSON object at server side with its specific format, something like:

{
    "firstName": "John",
    "lastName": "Smith",
    "address": {
        "streetAddress": "21 2nd Street",
        "city": "New York",
        "state": "NY",
        "postalCode": 10021
    },
    "phoneNumbers": [
        "212 732-1234",
        "646 123-4567"
    ]
}

Now Construct a list of inserted records in the database, see following sample code that showing how to construct list of records in JSON:

List mybeanList = new ArrayList();
mybeanList.add(myBean1);
mybeanList.add(myBean2);

JSONArray jsonArray = JSONArray.fromObject(mybeanList);
System.out.println("==== : "+jsonArray);

Map map = new HashMap();
map.put("beanlist", jsonArray);

JSONObject jsonObject = JSONObject.fromObject(map);
return jsonObject;

Finally parse the received JSON response inside your jsp (using javascript or any other alternatives)...

Go through with this tutorial , if you face any trouble with JSON.

Answer 2

Well you need to establish a connection with your database server side, pull the records out of the database ( possibly filtering based on data from the ajax request? look at data attribute for .getJSON ) then your server needs to format this in JSON. In PHP you'll use json_encode($data_array) -- then simply echo this back to the client. For the jQuery request:

   $.getJSON('http://site.com/ajax/get-latest-posts', {
         success: function(jsonObject) {
             // jsonObject[0].author, for example.
         }
   });