java - 如何解决此错误，无法从静态上下文引用非静态方法

Question

这个问题已经有答案了:

"Non-static method cannot be referenced from a static context" error (4 个回答)

已关闭 7 年前。

这是代码

protected Void doInBackground(String... params) {
   String reg_url = "http://10.0.2.2/";
    String method = params [0];
    if (method.equals("register") ){
        String first_name = params [1];
        String last_name = params [2];
        String address = params [3];
        String email = params [4];
        String password = params [5];

        try {
            URL url = new URL(reg_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
            HttpURLConnection.setRequestMethod("POST");
            HttpURLConnection.setDoOutput(True);

        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
    return null;
}

我在这两行上收到错误

HttpURLConnection.setRequestMethod("POST");
            HttpURLConnection.setDoOutput(True);

关于 set.RequestMethod("POST") 和 "setDoOutput(true); 错误表示无法从静态上下文引用非静态方法。这一定是一个愚蠢的错误，但我就是无法弄清楚，所以有人可以帮我解决这个问题吗？

Answer 1

使用您在调用 openConnection 中获得的实例:

        HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
        httpURLConnection.setRequestMethod("POST");
        httpURLConnection.setDoOutput(true);

请注意，Java 区分大小写。 HttpURLConnection 是类名。 httpURLConnection 是一个引用该类实例的变量。