HttpUrlConnection“ PUT”请求也发送“ GET”请求

Question

我的问题是，当我使用HttpURLConnection向我的PUT发送REST API请求时，它先发送GET请求，然后发送PUT请求。我想知道我必须发送PUT请求的任何代码是否导致它也发送GET请求。

我知道在我的Android代码中会发生此问题，因为我也使用Postman发送PUT请求，但是我从来没有遇到问题。

下面是我用来发送HttpUrlConnection请求的函数的副本。

public String HTTPConnection(String requestType, String url, String input, Context context, Activity activity){
        HttpURLConnection connection = null;
        try {
            URL OBJ = new URL(url);
            connection = (HttpURLConnection) OBJ.openConnection();
            connection.setRequestMethod(requestType);
            switch (requestType.toLowerCase()) {
                case "get":
                    BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
                    String inputLine;
                    StringBuilder response = new StringBuilder();
                    int i = 1;
                    while ((inputLine = in.readLine()) != null) {
                        response.append(inputLine);
                        i++;
                    }
                    in.close();
                    return response.toString();
                case "put":
                    if (!input.equals("")){
                        OBJ.openStream();
                        connection.setRequestProperty("Content-type", "application/json");
                        connection.setRequestProperty("Accept", "application/json");
                        connection.setDoOutput(true);
                    }
                    Writer writer = new BufferedWriter(new OutputStreamWriter(connection.getOutputStream(), "UTF-8"));
                    writer.write(input);
                    writer.flush();
                    writer.close();
                    connection.getInputStream();
                    return "";
                default:
                    return "";
            }
        } catch (IOException e){
            e.printStackTrace();
            return null;
        }
    }

Answer 1

OBJ.openStream();发送GET请求（请参阅java.net.URL.openStream），因为它打开了用于读取该URL内容的输入流。