Java getInputStream SocketTimeoutException而不是NoRouteToHostException

在Linux（RHEL）上嘗試打開多個輸入流（在單獨的線程中）時，發生了一個奇怪的問題。該行爲在Windows上按預期工作。Java getInputStream SocketTimeoutException而不是NoRouteToHostException

我正在踢掉3個線程來打開https連接到3個不同的服務器。這三個都是無效的IP地址（在這個測試用例中），所以我期望每個人都有一個NoRouteToHostException。前兩個按預期返回，並且很快。（請參閱下面的堆棧跟蹤）然而，第三個（以及我以這種方式測試時的第四個）不會給出無路由例外。他們等待很長時間，然後給出一個SocketTimeoutException（請參閱下面的其他堆棧跟蹤）。這需要很長時間才能回來，並且不能準確表達連接問題。

問題的代碼行是：

reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));

有沒有人見過這樣的事情之前？ REHL上的套接字是否存在多線程問題，或者某些地方限制了多少可以同時連接的地方......或者......什麼？

預計堆棧跟蹤，因爲收到了前兩個條件：

java.net.NoRouteToHostException: No route to host 
     at java.net.PlainSocketImpl.socketConnect(Native Method) 
     at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333) 
     at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195) 
     at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182) 
     at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366) 
     at java.net.Socket.connect(Socket.java:529) 
     at com.sun.net.ssl.internal.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:559) 
     at sun.net.NetworkClient.doConnect(NetworkClient.java:158) 
     at sun.net.www.http.HttpClient.openServer(HttpClient.java:394) 
     at sun.net.www.http.HttpClient.openServer(HttpClient.java:529) 
     at sun.net.www.protocol.https.HttpsClient.(HttpsClient.java:272) 
     at sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:329) 
     at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:172) 
     at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:916) 
     at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:158) 
     at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1177) 
     at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:234)

意外的堆棧跟蹤，3日爲接受：

java.net.SocketTimeoutException: connect timed out 
     at java.net.PlainSocketImpl.socketConnect(Native Method) 
     at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333) 
     at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195) 
     at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182) 
     at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366) 
     at java.net.Socket.connect(Socket.java:529) 
     at com.sun.net.ssl.internal.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:559) 
     at sun.net.NetworkClient.doConnect(NetworkClient.java:158) 
     at sun.net.www.http.HttpClient.openServer(HttpClient.java:394) 
     at sun.net.www.http.HttpClient.openServer(HttpClient.java:529) 
     at sun.net.www.protocol.https.HttpsClient.(HttpsClient.java:272) 
     at sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:329) 
     at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:172) 
     at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:916) 
     at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:158) 
     at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1177) 
     at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:234)

來源

2011-01-06 Jon