Java can not receive data from AJAX POST

Question

I am a newbie of jquery. I am testing a very simple example. Server side (use java) receives data from client side, print it at console. Then response to client side another string.

At client side, I use:

 $.ajax({ type: "POST", url: "http://localhost:8080/", data: { Name: "sanmao", Password: "sanmaoword" }, contentType: "application/json; charset=utf-8", dataType: "jsonp", jsonp: "jsonpcallback", jsonpCallback: "bc", success: function(response) { alert(response[0].name + " " + response[1].name); //$("#msg").html(decodeURI(data)); }, error: function() { } ); 

At servcer side, I use:

InputStream is = exchange.getRequestBody();
        BufferedReader in = new BufferedReader(new InputStreamReader(is));

        String temp = "";
        try {

            // s = ArticleExtractor.INSTANCE.getText(in);
            temp = in.readLine();
            System.out.println("client request: " + temp);
        } catch (IOException e) {
            System.out.println("Processing failed");
        }

        Headers responseHeaders = exchange.getResponseHeaders();

        responseHeaders.set("Content-Type", "text/plain");

        OutputStream responseBody = exchange.getResponseBody();
        String s = "bc([{\"lng\":\"" + lng1 + "\",\"lat\":\"" + lat1 + "\",\"name\":\"" + name1 + "\"},{\"lng\":\""
                + lng2 + "\",\"lat\":\"" + lat2 + "\",\"name\":\"" + name2 + "\"}])";
        exchange.sendResponseHeaders(200, 0);
        responseBody.write(s.getBytes());
        responseBody.close();

But it does not work. If I remove the "data:..." and "contentType...". Client side can receive the response string. But server side can not receive the inbound string.

Can anybody tell me why?

Answer 1

jQuery can't create JSON for you. You have to manually convert the object yourself. You can use JSON.stringify :

data: JSON.stringify({
    Name: "sanmao",
    Password: "sanmaoword"
}),

When you pass an object as the data without doing this, jQuery simply converts it to a list of key value pairs which is sent in the post (in format key1=val1&key2=val2... instead of JSON).