android - 为什么tomcat依赖wi-fi

Question

我正在 GCM (Android) 上开发示例应用程序。在其中我使用 tomcat 服务器发送消息。以及接收消息的设备。一切正常，除非我的 wifi 关闭。一旦我的 wi-fi 关闭，我就停止向我的设备接收消息，并且在浏览器上我收到以下错误。任何人都可以告诉 wifi 和 GCM 服务之间的连接是什么吗？

HTTP Status 500 -

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

java.net.UnknownHostException: android.googleapis.com
    java.net.PlainSocketImpl.connect(Unknown Source)
    java.net.SocksSocketImpl.connect(Unknown Source)
    java.net.Socket.connect(Unknown Source)
    com.sun.net.ssl.internal.ssl.SSLSocketImpl.connect(Unknown Source)
    com.sun.net.ssl.internal.ssl.BaseSSLSocketImpl.connect(Unknown Source)
    sun.net.NetworkClient.doConnect(Unknown Source)
    sun.net.www.http.HttpClient.openServer(Unknown Source)
    sun.net.www.http.HttpClient.openServer(Unknown Source)
    sun.net.www.protocol.https.HttpsClient.<init>(Unknown Source)
    sun.net.www.protocol.https.HttpsClient.New(Unknown Source)
    sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(Unknown Source)
    sun.net.www.protocol.http.HttpURLConnection.plainConnect(Unknown Source)
    sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(Unknown Source)
    sun.net.www.protocol.http.HttpURLConnection.getOutputStream(Unknown Source)
    sun.net.www.protocol.https.HttpsURLConnectionImpl.getOutputStream(Unknown Source)
    com.google.android.gcm.server.Sender.post(Sender.java:479)
    com.google.android.gcm.server.Sender.post(Sender.java:458)
    com.google.android.gcm.server.Sender.sendNoRetry(Sender.java:170)
    com.google.android.gcm.server.Sender.send(Sender.java:121)
    com.google.android.gcm.demo.server.SendAllMessagesServlet.doPost(SendAllMessagesServlet.java:82)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

note The full stack trace of the root cause is available in the Apache Tomcat/6.0.33 logs.

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Answer 1

如果发送通知，它首先从您的服务器发送到 Google GCM 服务器，然后从 GCM 服务器发送到手机。两个链接都必须启动并运行才能收到通知。

您关闭 WiFi 时似乎中断了服务器与互联网的连接。它不再能够连接到 Google 服务器。