我试图用这种方法从Web服务器下载XML文本文件:java.net.SocketException异常:网络是无法访问:连接
static void download (String url , String fileName) throws IOException{
FileWriter xmlWriter;
xmlWriter = new FileWriter(fileName);
System.out.println("URL to download is : " + url);
// here Exception is thrown/////////////////////////////////
BufferedReader inputTxtReader = new BufferedReader
(new BufferedReader(new InputStreamReader(addURL.openStream())));
////////////////////////////////////////////////////////
String str ;
String fileInStr = "";
str = inputTxtReader.readLine();
while (!(str == null) ){///&& !(str.equals("</tv>"))
fileInStr += (str + "\r\n");
str = inputTxtReader.readLine();
}
xmlWriter.write(fileInStr);
xmlWriter.flush();
xmlWriter.close();
System.out.println("File Downloaded");
}
有时,这种异常被抛出(我指定的地方是代码) :
java.net.SocketException: Network is unreachable: connect
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.Socket.connect(Socket.java:518)
at java.net.Socket.connect(Socket.java:468)
at sun.net.NetworkClient.doConnect(NetworkClient.java:157)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:389)
at sun.net.www.http.HttpClient.openServer(HttpClient.java:516)
at sun.net.www.http.HttpClient.<init>(HttpClient.java:233)
at sun.net.www.http.HttpClient.New(HttpClient.java:306)
at sun.net.www.http.HttpClient.New(HttpClient.java:318)
at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:788)
at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:729)
at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:654)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:977)
at java.net.URL.openStream(URL.java:1009)
at MessagePanel.download(MessagePanel.java:640)
at WelcomThread.run(MainBody2.java:891)
请指引我
谢谢大家。
'!(str == null)'看起来很混乱,你应该写'str!= null'。 – TC1
你在哪里以及如何初始化addURL变量? – pap