[英]Why is my message sent only once in Java socket server?
有一個服務器被認為可以同時為多個客戶端提供服務。
因此,當客戶端連接時,他被添加到客戶端陣列。 當服務器收到消息后,它將發送給所有客戶端。 當連接一個客戶端時,它可以完美工作,但是當我同時有2個客戶端時,該消息僅發送一次,此后不再起作用。 有什么問題?
服務器
static DataInputStream inputStream;
static DataOutputStream outputStream;
static ServerSocket serverSocket;
static final int PORT = 3003;
static Socket someClient;
static List<Socket> clients = new ArrayList<>();
public Server()
{
start();
}
public static void main(String[] args) throws IOException
{
try{
serverSocket = new ServerSocket(PORT);
print("Server started on " + serverSocket.getInetAddress().getHostAddress());
while (true)
{
someClient = serverSocket.accept();
new Server();
}
} catch (Exception e){
e.printStackTrace();
}
}
@Override
public void run()
{
try{
clients.add(someClient);
print("Connected from " + someClient.getInetAddress().getHostAddress());
InputStream sin = someClient.getInputStream();
OutputStream sout = someClient.getOutputStream();
inputStream = new DataInputStream(sin);
outputStream = new DataOutputStream(sout);
String message;
while (true)
{
message = inputStream.readUTF();
print(message);
for (int i = 0; i < clients.size(); i++)
{
Socket client = clients.get(i);
OutputStream os = client.getOutputStream();
DataOutputStream oss = new DataOutputStream(os);
oss.writeUTF(message);
}
}
} catch (Exception e){
e.printStackTrace();
}
}
客戶
socket = new Socket("0.0.0.0", 3003);
InputStream sin = socket.getInputStream();
OutputStream sout = socket.getOutputStream();
inputStream = new DataInputStream(sin);
outputStream = new DataOutputStream(sout);
sendButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if(key != null && key.length() == 16)
{
Date date = new Date();
String msg = ">> " + nickname + ": " + messageField.getText()+" | " + date.getHours()+":"+date.getMinutes()+"\n";
try {
outputStream.writeUTF(Encrypt.AESEncrypt(key, msg));
} catch (IOException e1) {
e1.printStackTrace();
}
messageField.setText("");
}
else if(key == null)
JOptionPane.showMessageDialog(J_Frame, "Your key field is empty");
else if(key.length() != 16)
JOptionPane.showMessageDialog(J_Frame, "Key's length should be 16 symbols");
}
});
while (true)
{
String message;
message = inputStream.readUTF();
append("\n" + Encrypt.AESDecrypt(key, message));
}
} catch (Exception e1) {
clear();
append(">> Unable to connect to the server.");
hideButtons();
}
每次客戶端連接到服務器時,它都會替換以前的連接:
while (true)
{
someClient = serverSocket.accept();
...
}
someClient
是靜態的:
static Socket someClient;
這意味着它被所有線程共享。 另外,對它的訪問不會以任何方式同步,這意味着不能保證對其值的更改對於其他線程是可見的。
正如Peter Lawrey在評論中指出的那樣,流還必須是非靜態的:
static DataInputStream inputStream;
static DataOutputStream outputStream;
實際上,您始終從“最新” inputStream
讀取的事實可能是您描述的行為的主要原因。 outputStream
似乎未使用,因此最好將其刪除。
除此之外,可能還需要刷新OutputStreams
才能實際發送數據。
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