我正在尝试使用下面的代码从URL下载Web内容：

URL content = new URL(urlstr);
    HttpURLConnection urlConnection = (HttpURLConnection) content.openConnection();

    try {
        InputStream in = urlConnection.getInputStream();
        InputStreamReader isw = new InputStreamReader(in);

        String existing_string = "";
        StringBuilder builder = new StringBuilder(existing_string);
        int data = isw.read();
        while (data != -1) {
            char current = (char) data;
            builder.append(current);
            data = isw.read();
        }

我得到的错误是Cannot resolve method openConnection()。导入语句如下所示：

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;

我已经看了 * 几乎 * 所有有关这方面的问题，但我似乎没有得到它的工作。