java - 检查 url 是否有效时出现错误

Question

我想使用以下 Java 代码不断监视站点是否处于 Activity 状态:

URL url1 = new URL ("http://www.google.com");
HttpURLConnection code = (HttpURLConnection)url1.openConnection();
System.out.println(code.getResponseCode());

但我不断收到错误:

Exception in thread "main" java.net.UnknownHostException: www.google.com
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:158)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:384)
    at java.net.Socket.connect(Socket.java:546)
    at java.net.Socket.connect(Socket.java:495)
    at sun.net.NetworkClient.doConnect(NetworkClient.java:178)
    at sun.net.www.http.HttpClient.openServer(HttpClient.java:409)
    at sun.net.www.http.HttpClient.openServer(HttpClient.java:530)
    at sun.net.www.http.HttpClient.<init>(HttpClient.java:240)
    at sun.net.www.http.HttpClient.New(HttpClient.java:321)
    at sun.net.www.http.HttpClient.New(HttpClient.java:338)
    at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:935)
    at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:876)
    at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:801)
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1139)
    at java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:397)
    at java.net.HttpURLConnection.getResponseMessage(HttpURLConnection.java:463)

我做错了什么吗？请指教。谢谢。

Answer 1

你有代理吗？它可能需要您的代理设置才能正常工作..