我是java中服务器概念的新手。我已经设置了一个非常简单的服务器（大多数都是从网上复制过来的）我希望它能以“状态”发送它，但我希望它只发送一次。这是我的代码，它可能更清楚。
服务器：
package components;
import java.io.DataInputStream;
import java.io.PrintStream;
import java.io.IOException;
import java.net.Socket;
import java.net.ServerSocket;
public class mainServer {
// The server socket.
private static ServerSocket serverSocket = null;
// The client socket.
private static Socket clientSocket = null;
// This chat server can accept up to maxClientsCount clients' connections.
private static final int maxClientsCount = 3;
private static final clientThread[] threads = new clientThread[maxClientsCount];
public static void main(String args[]) {
// The default port number.
int portNumber = 3333;
if (args.length < 1) {
System.out
.println("Usage: java MultiThreadChatServer <portNumber>\n"
+ "Now using port number=" + portNumber);
} else {
portNumber = Integer.valueOf(args[0]).intValue();
}
/*
* Open a server socket on the portNumber (default 2222). Note that we can
* not choose a port less than 1023 if we are not privileged users (root).
*/
try {
serverSocket = new ServerSocket(portNumber);
} catch (IOException e) {
System.out.println(e);
}
/*
* Create a client socket for each connection and pass it to a new client
* thread.
*/
while (true) {
try {
clientSocket = serverSocket.accept();
int i = 0;
for (i = 0; i < maxClientsCount; i++) {
if (threads[i] == null) {
(threads[i] = new clientThread(clientSocket, threads)).start();
break;
}
}
if (i == maxClientsCount) {
PrintStream os = new PrintStream(clientSocket.getOutputStream());
os.println("Server too busy. Try later.");
os.close();
clientSocket.close();
}
} catch (IOException e) {
System.out.println(e);
}
}
}
}
/*
* The chat client thread. This client thread opens the input and the output
* streams for a particular client, ask the client's name, informs all the
* clients connected to the server about the fact that a new client has joined
* the chat room, and as long as it receive data, echos that data back to all
* other clients. When a client leaves the chat room this thread informs also
* all the clients about that and terminates.
*/
class clientThread extends Thread {
private DataInputStream is = null;
private PrintStream os = null;
private Socket clientSocket = null;
private final clientThread[] threads;
private int maxClientsCount;
public clientThread(Socket clientSocket, clientThread[] threads) {
this.clientSocket = clientSocket;
this.threads = threads;
maxClientsCount = threads.length;
}
public void run() {
int maxClientsCount = this.maxClientsCount;
clientThread[] threads = this.threads;
try {
/*
* Create input and output streams for this client.
*/
is = new DataInputStream(clientSocket.getInputStream());
os = new PrintStream(clientSocket.getOutputStream());
os.println("Enter your name.");
while (true) {
String line = is.readLine();
if (line.startsWith("/quit")) {
break;
}
if (line.startsWith("Home")) {
os.println("Server in Home mode");
}
if (line.startsWith("Search / Modify")){
System.out.println("Server in search and modify mo");
}
}
for (int i = 0; i < maxClientsCount; i++) {
if (threads[i] != null && threads[i] != this) {
threads[i].os.println("*** The user "
+ " is leaving the chat room !!! ***");
}
}
os.println("*** Bye " + " ***");
/*
* Clean up. Set the current thread variable to null so that a new client
* could be accepted by the server.
*/
for (int i = 0; i < maxClientsCount; i++) {
if (threads[i] == this) {
threads[i] = null;
}
}
/*
* Close the output stream, close the input stream, close the socket.
*/
is.close();
os.close();
clientSocket.close();
} catch (IOException e) {
}
}
}
主： 所以此刻它不断地通过输出流发送单词home，然后服务器发回字符串“服务器处于Home状态”，然后打印出来。如何让它只发送一次，这对我来说能够检测到我的gui上按下了哪个按钮并在服务器上发送命令时非常有用。
package components;
//Import all libraries
import java.awt.EventQueue;
public class MainFrame implements Runnable {
//declare Jpanel
private static JFrame frmHome;
// The client socket
private static Socket clientSocket = null;
// The output stream
private static PrintStream os = null;
// The input stream
private static DataInputStream is = null;
private static BufferedReader inputLine = null;
private static boolean closed = false;
public static void main(String[] args){
// The default port.
int portNumber = 3333;
// The default host.
String host = "localhost";
System.out
.println("Usage: java MultiThreadChatClient <host> <portNumber>\n"
+ "Now using host=" + host + ", portNumber=" + portNumber);
/*
* Open a socket on a given host and port. Open input and output streams.
*/
try {
clientSocket = new Socket(host, portNumber);
inputLine = new BufferedReader(new InputStreamReader(System.in));
os = new PrintStream(clientSocket.getOutputStream());
is = new DataInputStream(clientSocket.getInputStream());
} catch (UnknownHostException e) {
System.err.println("Don't know about host " + host);
} catch (IOException e) {
System.err.println("Couldn't get I/O for the connection to the host "
+ host);
}
/*
* If everything has been initialized then we want to write some data to the
* socket we have opened a connection to on the port portNumber.
*/
if (clientSocket != null && os != null && is != null) {
try {
/* Create a thread to read from the server. */
new Thread(new MainFrame()).start();
while (!closed) {
os.println("Home");
}
/*
* Close the output stream, close the input stream, close the socket.
*/
os.close();
is.close();
clientSocket.close();
} catch (IOException e) {
System.err.println("IOException: " + e);
}
}
}
/*
* Create a thread to read from the server. (non-Javadoc)
*
* @see java.lang.Runnable#run()
*/
public void run() {
/*
* Keep on reading from the socket till we receive "Bye" from the
* server. Once we received that then we want to break.
*/
MainFrame window = new MainFrame();
MainFrame.frmHome.setVisible(true);
String responseLine;
try {
while ((responseLine = is.readLine()) != null) {
System.out.println(responseLine);
if (responseLine.indexOf("*** Bye") != -1)
break;
}
closed = true;
} catch (IOException e) {
System.err.println("IOException: " + e);
}
}
public MainFrame() {
initialize();
}
//function to make window visible
void setVisible() {
main(null);
}
private void initialize() {
//Initialise Main window with 3 options.
frmHome = new JFrame();
frmHome.setTitle("Home");
frmHome.setBounds(100, 100, 300, 372);
frmHome.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frmHome.getContentPane().setLayout(null);
frmHome.setResizable(false);
JLabel lblWelcomeToSrs = new JLabel("Welcome to SRS");
lblWelcomeToSrs.setFont(new Font("Tahoma", Font.PLAIN, 14));
lblWelcomeToSrs.setBounds(86, 183, 112, 14);
frmHome.getContentPane().add(lblWelcomeToSrs);
//initialise all buttons and labels of window.
JButton btnAdStu = new JButton("Add a student");
btnAdStu.setBounds(10, 207, 126, 23);
btnAdStu.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
AddStudentFrame adus;
try {
adus = new AddStudentFrame();
adus.setVisible();
frmHome.setVisible(false);
} catch (ParseException e) {
e.printStackTrace();
}
}
});
frmHome.getContentPane().add(btnAdStu);
JButton btnCheckStud = new JButton("Search / Modify");
btnCheckStud.setBounds(146, 207, 127, 23);
btnCheckStud.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
SearchFrame searchFrame;
searchFrame = new SearchFrame();
searchFrame.setVisible();
}
});
frmHome.getContentPane().add(btnCheckStud);
JLabel lblNewLabel = new JLabel("");
lblNewLabel.setBounds(0, 0, 0, 0);
frmHome.getContentPane().add(lblNewLabel);
JLabel lblCreatedByRmi = new JLabel("Created by R\u00E9mi Tuyaerts");
lblCreatedByRmi.setBounds(147, 318, 184, 14);
frmHome.getContentPane().add(lblCreatedByRmi);
JButton btnNewButton = new JButton("Complete List of Students");
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
CompleteListFrame studentList = new CompleteListFrame();
frmHome.setVisible(false);
studentList.setVisible();
}
});
btnNewButton.setBounds(52, 241, 184, 23);
frmHome.getContentPane().add(btnNewButton);
// Button to set up the database
JButton btnFillInDatabase = new JButton("Fill in database");
btnFillInDatabase.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
StudentStoring.student1();
StudentStoring.student2();
StudentStoring.student3();
StudentStoring.student4();
}
});
btnFillInDatabase.setBounds(80, 276, 126, 23);
frmHome.getContentPane().add(btnFillInDatabase);
// wonderful pictures of his excellence design by Yasser
JLabel lblNewLabel_1 = new JLabel("");
Image img = new ImageIcon(frmHome.getClass().getResource("/michaelchung.jpg")).getImage();
lblNewLabel_1.setIcon(new ImageIcon(img));
lblNewLabel_1.setBounds(80, 11, 120, 148);
frmHome.getContentPane().add(lblNewLabel_1);
}
}
答案 0 :(得分：1)
您必须决定是否要使用单个连接来回传输多条消息，或者是否要为每条消息建立新连接。
要保持单个连接，只需打开套接字（在客户端）并将其保留在某处。不要close()它，直到你实际上不再需要连接为止。
如果您希望每条消息使用一个连接，通过close()有效地通知消息的结尾，则应在关闭连接的那一侧使用setSoLinger()。这将为另一端提供一些时间来读取任何未决数据，检测数据的结束，并为会话的结束做准备，而不会进入＆＃34;套接字关闭＆＃34;异常。