Question

我使用RMI和套接字在客户端集之间传输文件。问题是当运行下面的代码时有时我在客户端获得此异常：

java.io.EOFException
at java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2671)
at java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:3146)
at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:858)
at java.io.ObjectInputStream.<init>(ObjectInputStream.java:354)
at javafxcyberwind.serverSocket.run(serverSocket.java:38)
at java.lang.Thread.run(Thread.java:748)

这是我的代码示例，例外情况在注释行中：

客户：

Server_MethodsPEER S = (Server_MethodsPEER) Naming.lookup("rmi://" + ip + ":" + port + "/" + email);
Server_Methods R = S.peer();
R.uploadToServer(fileName);
Socket s = new Socket(ip, R.getServerSocketPort());
File fres = new File(crep + fileName);
FileInputStream inf = new FileInputStream(fres);
ObjectOutputStream out = new ObjectOutputStream(s.getOutputStream());
byte buf[] = new byte[1024];
int nn;
while ((nn = inf.read(buf)) != -1) {
    out.write(buf, 0, nn);
}
out.close();
inf.close();
s.close();
fres.delete();

服务器：

public class serverSocket implements Runnable {

private final ServerSocket socketserver;
private Socket socket;
private final String ff;
private final String rp;

public serverSocket(ServerSocket s, String file, String rep) {
    socketserver = s;
    ff = file;
    rp = rep;
}

@Override
public void run() {
    try {
        socket = socketserver.accept();
        ObjectInputStream in = new ObjectInputStream(socket.getInputStream());//EOFException here
        FileOutputStream out = new FileOutputStream(new File(rp + ff));
        byte buf[] = new byte[1024];
        int n;
        while ((n = in.read(buf)) != -1) {
            out.write(buf, 0, n);
        }
        in.close();
        out.close();
        socket.close();
        socketserver.close();
    } catch (IOException e) {
        System.err.println("socket err");
    }
}
}

//ServerIMPL
ServerSocket sv;

public void uploadToServer(String fileName) throws RemoteException {
    try {
        sv = new ServerSocket(0);
    } catch (IOException ex) {
        Logger.getLogger(Cloud_ServeurIMPL.class.getName()).log(Level.SEVERE, null, ex);
    }
    Thread t = new Thread(new serverSocket(sv, file, crep));
    t.start();

    Client3_MethodsPEER M = (Client3_MethodsPEER) Naming.lookup("rmi://" + ip + ":" + port + "/" + email);
    Client3_Methods U = M.peer();
    U.uploadToServer(fileName);
    Socket s = new Socket(ip, U.getServerSocketPort());
    File fres = new File(crep + fileName);
    FileInputStream inf = new FileInputStream(fres);
    ObjectOutputStream out = new ObjectOutputStream(s.getOutputStream());
    byte buf[] = new byte[1024];
    int nn;
    while ((nn = inf.read(buf)) != -1) {
        out.write(buf, 0, nn);
    }
    out.close();
    inf.close();
    s.close();
    fres.delete();
    U.operation();//FileNotFoundException here (use the received files as arguments)
}

一切似乎都很好。为什么会发生这种情况以及如何解决？

Answer 1

FileNotFoundException有两个含义：

输入时，找不到文件，由于权限等原因无法打开文件。
在输出时，找不到目标目录，由于权限等原因无法写入

例如，如果您发送的文件名包含服务器上不存在的目录，您将从FileNotFoundException获得new FileOutputStream。

您的问题中没有足够的信息（即任何信息）可以对此进行更多说明。

然而：

您不需要此对象流，甚至数据输入/输出流。您只使用基本的read()和write()方法，因此您也可以直接使用套接字流。
你应该使用比1024字节更大的缓冲区，比如8192或其倍数。
您可以通过我对this question的回答中提供的技巧，为每个连接发送多个文件。

Java套接字EOFException

1 个答案: