未知主机异常

如何解决未知主机异常

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try { 
{
    long startTime = System.currentTimeMillis();

        String source=\"s\";
        String source1=\"s\";
        URL google = new URL(\"http://google.com/\"); 
        HttpURLConnection yc =(HttpURLConnection)google.openConnection(); 
        BufferedReader in = new BufferedReader(new InputStreamReader(yc.getInputStream())); 
        String inputLine;


        while ((inputLine = in.readLine()) != null) { 
            source=source.concat(inputLine);
        }
        in.close();

        yc.disconnect();

    }

long endTime1 = System.currentTimeMillis();
System.out.println(\"Total elapsed time in execution of method callMethod() is :\"+ (endTime1-startTime));


    } 
}

当我通过命令提示符尝试以上  我有

java.net.UnknownHostException: google.com 
at java.net.PlainSocketImpl.connect(Unknown Source) 
at java.net.Socket.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.plainConnect(Unknown Source) 
at sun.net.www.protocol.http.HttpURLConnection.connect(Unknown Source) 
at ScagntJavaHttp.httpMakeRequest(ScagntJavaHttp.java:185) 
at test.main(test.java:23)

有什么可以帮助我解决这个问题的吗？     

解决方法

我相信这是一个代理问题。 尝试查看浏览器中是否有代理定义，然后进行设置：

    ProxySelector.setDefault(new ProxySelector() {

        @Override
        public void connectFailed(URI uri,SocketAddress sa,IOException ioe) {
            throw new RuntimeException(\"Proxy connect failed\",ioe);
        }

        @Override
        public List select(URI uri) {
            return Arrays
                .asList(new Proxy(Proxy.Type.HTTP,new InetSocketAddress(proxyHost,proxyPort)));
        }
    });

若要查看IE中是否具有代理定义，请转到“工具”“ Internet选项”“连接”“ LAN设置”。     ,尝试从主机网址中删除

http://

时，获得

java.net.UnknownHostException

并检查您的互联网连接并且该主机已存在（使用google。。可能是安全的）