Question

我创建了代码来访问我下载的文件，但这不是作业所需要的。它希望我使用此处给出的URL访问信息。我不确定为什么我一直得到IO异常。

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

    int test = 0;
    int sum = 0;
    int i = 0;
    try{
    java.net.URL url = new java.net.URL("http://cs.armstrong.edu/liang/data/Scores.txt");
    Scanner input = new Scanner(url.openStream());
    while (input.hasNext()){
        int score = input.nextInt();
        sum += score;
        i++;
    }
    }
    catch(java.net.MalformedURLException ex){
        ex.printStackTrace();
    }
    catch(java.io.IOException ex){
    System.out.println("I/O Errors: no such file");
    }


    int avg = sum / i;
    System.out.println("The average is: " + avg);
    System.out.println("The sum is: " + sum);




}

栈跟踪

java.net.SocketException: Invalid argument: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.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 sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
at java.net.URL.openStream(Unknown Source)
at readfile.main(readfile.java:15)

线程“main”中的异常java.lang.ArithmeticException：/ by zero 在readfile.main（readfile.java:30）

Answer 1

代码完全正常。只需添加以下部分即可在连接之前设置代理详细信息。

//The follwing settings is needed for Connecting to internet from Local Network
System.getProperties().put("http.proxyHost", "ip.add.of.proxy");
System.getProperties().put("http.proxyPort", "80");
System.getProperties().put("http.proxyUser", "user_name"); // Your username
System.getProperties().put("http.proxyPassword", "*************"); // your password

并在 try catch 块中移动以下代码，否则如果连接失败，您将获得divide by zero例外。

int avg = sum / i;
System.out.println("The average is: " + avg);
System.out.println("The sum is: " + sum);

为什么我一直收到I / O异常？

1 个答案: