Java，Google App Engine和JSONArray / JSONObject

Question

I'm working on an assignment and I can't seem to get a response from my instructor or the TA. The goal of the assignment is to use the Google App Engine to deploy an app that takes the URL of an image, converts it into a byte stream, stores it in the DataStore, then calls it back to be viewed on another page.

I've been able to store the image, but retrieving it is another matter. We're supposed to use JSON arrays and objects to pass a string with the relevant data to a calling function, but Eclipse is telling me that GAE does not support JSON. Here's the error message:

org.json.simple.JSONArray is not supported by Google App Engine's Java runtime environment

Furthermore, the Eclipse console is telling

JSONArray cannot be resolved to a type

and

JSONObject cannot be resolved to a type

What's really odd about this is that the instructor himself uses JSON in his demo app. I wish I could get a response from him regarding this issue, but he's being dodgy and has been somewhat absent all term.

Anyway, here's what I've got. Please let me know if there's something I'm doing wrong. For the record, I'm not asking anyone to fix my code for me or give me working code - I'd just like a little help understanding my problem.

<%@ page import="java.util.*" %>
<%@ page import="javax.jdo.*" %>
<%@ page import="org.json.simple.*" %>

<%
    PersistenceManager pm = PMF.getPMF().getPersistenceManager();
    try {
        List<University> items = University.loadAll(pm);
        JSONArray array = new JSONArray();
        for (University item : items) {
            JSONObject object = new JSONObject();
            object.put("uname", item.getNameOfUniversity());
            object.put("photoURL", item.getURLOfImage());
            array.add(object);
        }
        out.write(array.toString());
    } finally {
        pm.close();
    }
%>

Answer 1

You need to add the missing jar file to your project .

Also, for easier JSON creating parsing you should take a look at JSON mapper libraries: GSON or Jackson .