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Creation JSON from Java-classes

Merits and demerits which can be found in other ways of creation XML, can appear correct for JSON. Probably, there is one more case of use of technologies of a pattern of performance. However, use JSON is logically closer to use of serialization of the applications given for lines, than to creation of performance of a status of the application. I am going to show you how to use org.json and toJSONObject () at creation toJSONObject () methods in your Java-classes. You JSONObject can be easy also serializovan in JSON. Listing 8 reminds our discussion about XML, showing toJSONObject () realization for Order a class.

Listing 8. toJSONObject () realization of a method for class Order

public JSONObject toJSONObject () {

JSONObject json = new JSONObject ();

json.put ("id", id);

json.put ("cost", getFormattedCost ());

json.put ("date", date);

JSONArray jsonItems = new JSONArray ();

for (Iterator <Item> iter =

items.iterator (); iter.hasNext ();) {

jsonItems.put (iter.next () .toJSONObject ());

}

json.put ("items", jsonItems);

return json;

}

As you can see, the API-interface org.json is very simple. JSONObject represents JavaScript-object (a communicative file) and carries out various put () methods which use String a key and value String, or another JSON type. JSONArray represents not numbered file, therefore it{him} put () the method requests only one value. Remember, that listing 8, alternative to creation jsonItems a file and the subsequent to this his{its} fastening for json object with put () a method, should cause json.accumulate ("items", iter.next () .toJSONObject ()); for each thing. accumulate () the method is similar put () except that he adheres value to the conducted the indexation file determined by a key.

Listing 9 shows, how serializovat` JSONObject and to write it{him} according to search servleta.

Listing 9. Generation serializovannogo JSON search from JSONObject

public void doGet (HttpServletRequest req, HttpServletResponse res)

throws java.io. IOException, ServletException {

        String custId = req.getParameter ("username");

        Customer customer = getCustomer (custId);

        res.setContentType ("application/x-json");

        res.getWriter () .print (customer.toJSONObject ());

}

toString () the method in JSONObject, called here, performs all job, therefore on your share does not remain, practically, anything. Remember, that the content type application/x-json is a little bit doubtful, during a spelling of these lines we did not come to a consensus to what MIME type JSON of it{him} should attribute{relate}. However, application/x-json - a reasonable choice. Listing 10 shows search of an example from this code servleta.

Listing 10. JSON-performance Customer-bean

{

"orders": [

{

"items": [

{

"price": " $49.99",

"description": " 512 Megabyte Type 1 CompactFlash card.

Manufactured by Oolong Industries ",

"name": " Oolong 512MB CF Card ",

"id": "i-55768"

},

{

"price": " $299.99",

"description": " 7.2 Megapixel digital camera featuring six

shooting modes and 3x optical zoom. Silver. ",

"name": " Fujak Superpix72 Camera ",

"id": "i-74491"

}

],

"date": "08-26-2005",

"cost": " $349.98",

"id": "o-11123"

}

],

"realname": " James Hyrax ",

"username": "jimmy66"

}