java - 读取 HTML 时的 Http 响应代码 429

Question

在java中，我想从URL(instagram)读取并保存所有HTML，但收到错误429(请求过多)。我认为这是因为我试图读取比请求限制更多的行。

StringBuilder contentBuilder = new StringBuilder();
try {
    URL url = new URL("https://www.instagram.com/username");
    URLConnection con = url.openConnection();
    InputStream is =con.getInputStream();
    BufferedReader in = new BufferedReader(new InputStreamReader(is));
    String str;
    while ((str = in.readLine()) != null) {
        contentBuilder.append(str);
    }
    in.close();
} catch (IOException e) {
    log.warn("Could not connect", e);
}
String html = contentBuilder.toString();

错误是这样的；

Could not connect
java.io.IOException: Server returned HTTP response code: 429 for URL: https://www.instagram.com/username/

它还表明由于这一行而发生错误

InputStream is =con.getInputStream();

有谁知道我为什么会收到此错误和/或如何解决它？

Answer 1

该问题可能是由于连接未关闭/断开造成的。对于用于自动关闭的输入 try-with-resources，即使在异常或返回时也很有用。此外，您还构建了一个 InputStreamReader，它将使用运行应用程序的计算机的默认编码，但您需要 URL 内容的字符集。readLine 返回没有行结尾的行(这通常非常有用)。所以添加一个。

StringBuilder contentBuilder = new StringBuilder();
try {
    URL url = new URL("https://www.instagram.com/username");
    URLConnection con = url.openConnection();
    try (BufferedReader in = new BufferedReader(
                new InputStreamReader(con.getInputStream(), "UTF-8"))) {
        String line;
        while ((line = in.readLine()) != null) {
            contentBuilder.append(line).append("\r\n");
        }
    } finally {
        con.disconnect();
    } // Closes in.
} catch (IOException e) {
    log.warn("Could not connect", e);
}
String html = contentBuilder.toString();