HttpURLConnection 一直超时

怎么这么简单的程序一直都提示connnection timeout？
import java.net.HttpURLConnection;
import java.net.URL;

public class AssureUploadSuccess {
public static void main(String []args){
try{
URL url = new URL("http://www.baidu.com");
HttpURLConnection httpCon = (HttpURLConnection) url.openConnection();
httpCon.setConnectTimeout(30000);
httpCon.setReadTimeout(30000);
httpCon.setDoOutput(true);
httpCon.setRequestMethod("POST");
httpCon.connect();
}catch(Exception e)
{
e.printStackTrace();
}
}
}
错误提示：
java.net.ConnectException: Connection timed out: connect
at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at sun.net.NetworkClient.doConnect(Unknown Source)
at sun.net.www.http.HttpClient.openServer(Unknown Source)
at sun.net.www.http.HttpClient.openServer(Unknown Source)
at sun.net.www.http.HttpClient.<init>(Unknown Source)
at sun.net.www.http.HttpClient.New(Unknown Source)
at sun.net.www.http.HttpClient.New(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect0(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(Unknown Source)
at sun.net.www.protocol.http.HttpURLConnection.connect(Unknown Source)
at AssureUploadSuccess.main(AssureUploadSuccess.java:25)