java教程-未知主机异常

Question

我正在尝试使用教程读取URL：http://docs.oracle.com/javase/tutorial/networking/urls/readingURL.html

import java.net.*;
import java.io.*;

public class URLReader {
    public static void main(String[] args) throws Exception {

        URL oracle = new URL("http://www.google.com/");
        BufferedReader in = new BufferedReader(new InputStreamReader(oracle.openStream()));
        String inputLine;

        while ((inputLine = in.readLine()) != null)
            System.out.println(inputLine);

        in.close();
    }

}

但我的情况越来越糟了。www.google.com是已知主机吗？

Exception in thread "main" java.net.UnknownHostException: www.google.com
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:195)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
    at java.net.Socket.connect(Socket.java:529)
    at java.net.Socket.connect(Socket.java:478)
    at sun.net.NetworkClient.doConnect(NetworkClient.java:163)
    at sun.net.www.http.HttpClient.openServer(HttpClient.java:395)
    at sun.net.www.http.HttpClient.openServer(HttpClient.java:530)
    at sun.net.www.http.HttpClient.<init>(HttpClient.java:234)
    at sun.net.www.http.HttpClient.New(HttpClient.java:307)
    at sun.net.www.http.HttpClient.New(HttpClient.java:324)
    at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:970)
    at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:911)
    at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:836)
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1172)
    at java.net.URL.openStream(URL.java:1010)
    at URLReader.main(URLReader.java:8)

Answer 1

你是在代理服务器后面运行吗？这篇文章似乎暗示在这种情况下需要进行配置。

或者，程序可能挂起，或者您可能会看到异常堆栈跟踪。如果发生后两种事件中的任何一种，您可能必须设置代理主机，以便程序能够找到Oracle服务器。

Answer 2

你在代理背后吗？尝试在eclipse中设置代理或尝试

 java -DproxySet=true -DproxyHost=10.0.0.14 -DproxyPort=6588 JavApp

Answer 3

我认为它的网络错误检查您的互联网连接....