java - 如果我在创建对象时已经打开连接，是否需要执行 HTTPUrlConnection.connect() ？

Question

考虑下面的代码。由于我正在执行 url.openConnection()，connection.connect 是否多余？如果是，那么为什么我们有 .connect() 方法？是为了关闭连接后重新连接吗？

URL url;
        url = new URL(
                "http://api.longurl.org/v2/expand?format=json&title=1&user-agent=TwitterProject&url="
                        + someURL);
        HttpURLConnection connection;
        connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("GET");
        connection.setDoInput(true);
        connection.connect();
        BufferedReader in = new BufferedReader(new InputStreamReader(
                connection.getInputStream()));
        String line = null;
        String full = "";
        while ((line = in.readLine()) != null) {
            full = full + line;
        }
        jsonresponse = JSONObject.fromObject(full);

Answer 1

public abstract void connect() throws IOException

Opens a communications link to the resource referenced by this URL, if such a connection has not already been established. If the connect method is called when the connection has already been opened (indicated by the connected field having the value true), the call is ignored.

在您的情况下，调用将被忽略。

 connection = (HttpURLConnection) url.openConnection();// already established connection.