How to get data from server?

[justmonkey]

I have read many JSON examples which are all static data. Now I want to get dynamic JSON data from server( use Struts), I don't know how to get it in js. Here is my code.

/*TestAction.java*/

public class TestAction extends Action{
    public ActionForward execute(ActionMapping mapping, ActionForm form,
                                 HttpServletRequest request, HttpServletResponse response)
            throws ServletException {
        try {

            List progInfos = new ArrayList();

            ProgramInfo info = new ProgramInfo();
            info.setName("YUI get data test");
            info.setContent("testtesttest.");

            progInfos.add(info);
            JSONArray jsonProgInfos = JSONArray.fromObject(progInfos);

            request.setAttribute("jsonProgInfos", jsonProgInfos.toString());

            return mapping.findForward("main");
            
        } catch (Exception e) {
            logger.error(e);
        }

        return null;
    }
}

/*results.js*/

Ext.onReady(function() {
    var testResults, ds, columnModel, resultsGrid;

    // I don't know how to access data from server, the following sentence seems make no sense 
    testResults = eval(<!--(String)request.getAttribute("jsonProgInfos")-->);           


    ds = new Ext.data.Store({
        proxy: new Ext.data.MemoryProxy(testResults),
        reader: new Ext.data.ArrayReader({id: 0}, [
        {name: 'name'},
        {name: 'content'}
       ])
    });
    ds.load();


    columnModel = new Ext.grid.ColumnModel([{
        header: "Name",
        dataIndex: 'name',
        width: 100
    }, {
        header: "Content",
        dataIndex: 'content',
        width: 400,
        align: 'right'
    }
   ]);

    resultsGrid = new Ext.grid.Grid('test-grid', {
        ds: ds,
        cm:columnModel
    });
    resultsGrid.render();
});

Anyone can help me? Thanks.

[bone]

You need to read stuff instead of asking.


http://www-128.ibm.com/developerworks/library/j-ajax1/
http://adaptivepath.com/publications...ves/000385.php
http://www-128.ibm.com/developerwork...Mastering+Ajax (start at part 1 and go to part 10)

[tryanDLS]

MemoryProxy is used to load data that's hard-coded in a JS var. Use HttpProxy to make a request to the server for data and process the response object. Look at the examples.

[tab]

Here is a Java example of generating some JSON

		JSONObject object = new JSONObject();
		object.put("id","1");
		object.put("Title","Freds JSON Example");
		object.put("Author","ME");
		JSONArray data = new JSONArray();
		data.put(object);
		JSONObject result = new JSONObject();
		result.put("totalCount", "20");
		result.put("topics",data);

the fields "id", "Title", "Author", "totalcount" and "topics" have to align with the field definitions in the JSONReader object created in your JS code *AND* the fields have to be aligned (maybe transformed) into the columns in your JS code.

A good way to test the data is to access the data URL and make sure it has the right format (for example http://www.yui-ext.com/deploy/ext-1....get-nodes.php). You can also set breakpoints in the JSONReader.js code and watch what happens to the data as it comes back.

[justmonkey]

Thank you all. The question has been resolved

[spillo491]

Please can you post the code ?