使用HttpURLConnection使用JSON数据发出PUT请求不起作用

Question

我正在尝试使用HttpURLConnectionJava中的JSON数据进行PUT请求.我这样做的方式不起作用.我没有错误,所以我不知道问题是什么.

public static void main(String[] args) {

        URL url;
        try {
            url = new URL("http://fltspc.itu.dk/widget/515318fe17450f312b00153d/");
            HttpURLConnection hurl = (HttpURLConnection) url.openConnection();
            hurl.setRequestMethod("PUT");
            hurl.setDoOutput(true);
            hurl.setRequestProperty("Content-Type", "application/json");
            hurl.setRequestProperty("Accept", "application/json");

            String payload = "{'pos':{'left':45,'top':45}}";

            OutputStreamWriter osw = new OutputStreamWriter(hurl.getOutputStream());
            osw.write(payload);
            osw.flush();
            osw.close();
        } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

这是我实际上要做的请求:

我已经在同一个应用程序中对资源发出GET请求,但它运行正常.我将非常感谢有关如何调试的所有提示,或者我如何尝试以其他方式执行此操作.到目前为止,我只尝试使用OutputStream而不是,OutputStreamWriter但它既不起作用.

Answer 1

HttpURLConnection的Sun(Oracle)实现会缓存帖子的内容,除非您告诉它处于流模式.如果您开始与响应进行交互,则会发送内容,例如:

hurl.getResponseCode();

另外,根据RFC 4627,您不能在json中使用单引号(尽管某些实现似乎并不在意).

因此,将您的有效负载更改为:

String payload = "{\"pos\":{\"left\":45,\"top\":45}}";

这个例子适合我

public class HttpPut {
    public static void main(String[] args) throws Exception {
        Random random = new Random();
        URL url = new URL("http://fltspc.itu.dk/widget/515318fe17450f312b00153d/");
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("PUT");
        connection.setDoOutput(true);
        connection.setRequestProperty("Content-Type", "application/json");
        connection.setRequestProperty("Accept", "application/json");
        OutputStreamWriter osw = new OutputStreamWriter(connection.getOutputStream());
        osw.write(String.format("{\"pos\":{\"left\":%1$d,\"top\":%2$d}}", random.nextInt(30), random.nextInt(20)));
        osw.flush();
        osw.close();
        System.err.println(connection.getResponseCode());
    }
}