我正在尝试创建一个“信使”(仅用于真正的学习),并且对Socket / ServerSocket来说还很陌生,并且目前停留在使其成为网络部分。
另外,我确实知道ClientNetworking还不完整。我试图完成它,但是我很沮丧。
ServerMain:
public class ServerMain extends JFrame {
int WIDTH = 480;
int HEIGHT = 320;
String writeToConsole;
JPanel mainPanel, userPanel, consolePanel;
JTabbedPane tabbedPane;
JButton launchButton;
JTextArea console;
JTextField consoleInput;
JScrollPane consoleScroll;
public ServerMain() {
super("Messenger Server");
mainPanel = new JPanel();
mainPanel.setLayout(null);
Networking();
createConsolePanel();
userPanel = new JPanel();
userPanel.setLayout(null);
tabbedPane = new JTabbedPane();
tabbedPane.add(mainPanel, "Main");
tabbedPane.add(userPanel, "Users");
tabbedPane.add(consolePanel, "Console");
add(tabbedPane);
}
public static void main(String[] args) {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch(UnsupportedLookAndFeelException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
ServerMain frame = new ServerMain();
frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
frame.setSize(frame.WIDTH, frame.HEIGHT);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.setResizable(false);
}
public void Networking() {
ServerNetworking net;
try {
net = new ServerNetworking();
net.start();
} catch(Exception e) {
e.printStackTrace();
}
}
public void createConsolePanel() {
consolePanel = new JPanel();
consolePanel.setLayout(null);
console = new JTextArea();
console.setFont(new Font("", Font.PLAIN, 13 + 1/2));
console.setBounds(0, 0, WIDTH, HEIGHT - 100);
console.setEditable(false);
console.setLineWrap(true);
consoleInput = new JTextField(20);
consoleInput.setBounds(0, 0, WIDTH, 25);
consoleInput.setLocation(0, 240);
consoleInput.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent event) {
String input = consoleInput.getText();
if(input.equalsIgnoreCase("/sendmessage")) {
//console.append(input);
console.append("Input who you would like to send the message to:");
consoleInput.setText("");
} if (input.equalsIgnoreCase("/ban")) {
console.append("Who you would like to ban");
consoleInput.setText("");
}
}
});
consolePanel.add(console);
consolePanel.add(consoleInput);
}
public void consoleWrite(String write) {
console.append(write);
}
}
ServerNetworking(线程):
public class ServerNetworking extends Thread {
private static ServerSocket servSock;
private static final int PORT = 1234;
private static void handleClient() {
Socket link = null;
try {
link = servSock.accept();
Scanner input = new Scanner(link.getInputStream());
PrintWriter output =
new PrintWriter(link.getOutputStream(),true);
int numMessages = 0;
String message = input.nextLine();
while (!message.equals("***CLOSE***")) {
System.out.println("Message received.");
numMessages++;
output.println("Message " +
numMessages + ": " + message);
message = input.nextLine();
}
output.println(numMessages + " messages received.");
} catch(IOException ioEx) {
ioEx.printStackTrace();
} finally {
try {
System.out.println( "\n* Closing connection... *");
link.close();
} catch(IOException ioEx) {
System.out.println("Unable to disconnect!");
System.exit(1);
}
}
}
public void run() {
System.out.println("Opening port...\n");
try {
servSock = new ServerSocket(PORT);
} catch(IOException ioEx) {
System.out.println("Unable to attach to port!");
System.exit(1);
} do {
handleClient();
} while (true);
}
}
ClientMain:
public class ClientMain extends JFrame {
int WIDTH = 640;
int HEIGHT = 480;
JTabbedPane tabbedPane;
JMenuBar topMenuBar;
JMenu userMenu, helpMenu, settingsMenu;
JRadioButtonMenuItem menuItem;
JPanel mainPanel, friendsPanel, groupsPanel, testPanel;
JLabel title;
JScrollPane consoleScrollPane;
JSplitPane friendsPane;
JTextArea messageArea, testArea;
JTextField testField;
Box box;
public ClientMain() {
super("Messenger Client");
Networking();
title = new JLabel("Client!");
title.setFont(new Font("Impact", Font.PLAIN, 32));
mainPanel = new JPanel();
mainPanel.setLayout(null);
mainPanel.add(title);
groupsPanel = new JPanel();
groupsPanel.setLayout(null);
friendsPanel = new JPanel();
friendsPanel.setLayout(null);
testPanel = new JPanel();
testPanel.setLayout(null);
testArea = new JTextArea();
testArea.setFont(new Font("", Font.PLAIN, 13 + 1/2));
testArea.setBounds(0, 0, WIDTH, HEIGHT - 100);
testArea.setEditable(false);
testArea.setLineWrap(true);
testField = new JTextField(20);
testField.setBounds(0, 380, 640, 25);
//testField.setLocation(0, HEIGHT - 50);
testField.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
ClientNet net = new ClientNet();
String input = null;
input = testField.getText();
testArea.append(input);
testField.setText("");
if(input.equalsIgnoreCase("/sendmessage")) {
testArea.append("\n Input who you would like to send the message to:");
input = null;
if(input.equalsIgnoreCase("Hello")) {
net.userEntry = input;
}
}
}
});
testPanel.add(testArea);
testPanel.add(testField);
tabbedPane = new JTabbedPane();
tabbedPane.add(mainPanel, "Main");
tabbedPane.add(friendsPanel, "Friends");
tabbedPane.add(groupsPanel, "Groups");
tabbedPane.add(testPanel, "Test");
topMenuBar = new JMenuBar();
userMenu = new JMenu("User");
settingsMenu = new JMenu("Settings");
helpMenu = new JMenu("Help");
menuItem = new JRadioButtonMenuItem("Something here");
userMenu.add(menuItem);
topMenuBar.add(userMenu, "User");
topMenuBar.add(settingsMenu, "Settings");
topMenuBar.add(helpMenu, "Help");
add(topMenuBar);
add(tabbedPane);
}
public static void main(String[] args) {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch(UnsupportedLookAndFeelException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
ClientMain frame = new ClientMain();
Insets insets = frame.getInsets();
frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
frame.setSize(frame.WIDTH, frame.HEIGHT);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.setResizable(false);
frame.setJMenuBar(frame.topMenuBar);
}
public void Networking() {
ClientNet net;
try {
net = new ClientNet();
net.start();
} catch(Exception e) {
e.printStackTrace();
}
}
public void createMenuBar() {
topMenuBar = new JMenuBar();
userMenu = new JMenu("User");
settingsMenu = new JMenu("Settings");
helpMenu = new JMenu("Help");
menuItem = new JRadioButtonMenuItem("MenuItem");
menuItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
}
});
topMenuBar.add(userMenu, "User");
topMenuBar.add(settingsMenu, "Settings");
topMenuBar.add(helpMenu, "Help");
}
public void getFriends(String username) {
}
}
ClientNetworking(线程):
public class ClientMain extends JFrame {
int WIDTH = 640;
int HEIGHT = 480;
JTabbedPane tabbedPane;
JMenuBar topMenuBar;
JMenu userMenu, helpMenu, settingsMenu;
JRadioButtonMenuItem menuItem;
JPanel mainPanel, friendsPanel, groupsPanel, testPanel;
JLabel title;
JScrollPane consoleScrollPane;
JSplitPane friendsPane;
JTextArea messageArea, testArea;
JTextField testField;
Box box;
public ClientMain() {
super("Messenger Client");
Networking();
title = new JLabel("Client!");
title.setFont(new Font("Impact", Font.PLAIN, 32));
mainPanel = new JPanel();
mainPanel.setLayout(null);
mainPanel.add(title);
groupsPanel = new JPanel();
groupsPanel.setLayout(null);
friendsPanel = new JPanel();
friendsPanel.setLayout(null);
testPanel = new JPanel();
testPanel.setLayout(null);
testArea = new JTextArea();
testArea.setFont(new Font("", Font.PLAIN, 13 + 1/2));
testArea.setBounds(0, 0, WIDTH, HEIGHT - 100);
testArea.setEditable(false);
testArea.setLineWrap(true);
testField = new JTextField(20);
testField.setBounds(0, 380, 640, 25);
//testField.setLocation(0, HEIGHT - 50);
testField.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
ClientNet net = new ClientNet();
String input = null;
input = testField.getText();
testArea.append(input);
testField.setText("");
if(input.equalsIgnoreCase("/sendmessage")) {
testArea.append("\n Input who you would like to send the message to:");
input = null;
if(input.equalsIgnoreCase("Hello")) {
net.userEntry = input;
}
}
}
});
testPanel.add(testArea);
testPanel.add(testField);
tabbedPane = new JTabbedPane();
tabbedPane.add(mainPanel, "Main");
tabbedPane.add(friendsPanel, "Friends");
tabbedPane.add(groupsPanel, "Groups");
tabbedPane.add(testPanel, "Test");
topMenuBar = new JMenuBar();
userMenu = new JMenu("User");
settingsMenu = new JMenu("Settings");
helpMenu = new JMenu("Help");
menuItem = new JRadioButtonMenuItem("Something here");
userMenu.add(menuItem);
topMenuBar.add(userMenu, "User");
topMenuBar.add(settingsMenu, "Settings");
topMenuBar.add(helpMenu, "Help");
add(topMenuBar);
add(tabbedPane);
}
public static void main(String[] args) {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch(UnsupportedLookAndFeelException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
ClientMain frame = new ClientMain();
Insets insets = frame.getInsets();
frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
frame.setSize(frame.WIDTH, frame.HEIGHT);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.setResizable(false);
frame.setJMenuBar(frame.topMenuBar);
}
public void Networking() {
ClientNet net;
try {
net = new ClientNet();
net.start();
} catch(Exception e) {
e.printStackTrace();
}
}
public void createMenuBar() {
topMenuBar = new JMenuBar();
userMenu = new JMenu("User");
settingsMenu = new JMenu("Settings");
helpMenu = new JMenu("Help");
menuItem = new JRadioButtonMenuItem("MenuItem");
menuItem.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
}
});
topMenuBar.add(userMenu, "User");
topMenuBar.add(settingsMenu, "Settings");
topMenuBar.add(helpMenu, "Help");
}
public void getFriends(String username) {
}
}
这是我启动服务器然后启动客户端时遇到的错误:
它不应该说“收到消息”,因为我实际上没有发送消息
Opening port...
Message received.
* Closing connection... *
Exception in thread "Thread-1" java.util.NoSuchElementException: No line found
at java.util.Scanner.nextLine(Unknown Source)
at Server.ServerNetworking.handleClient(ServerNetworking.java:29)
at Server.ServerNetworking.run(ServerNetworking.java:53)
最佳答案
我认为问题在于ServerNetworking
类中的以下循环:
while (!message.equals("***CLOSE***")) {
System.out.println("Message received.");
numMessages++;
output.println("Message " +
numMessages + ": " + message);
message = input.nextLine();
}
此代码的问题在于,在从客户端收到完整的消息后,最后一行代码
message = input.nextLine();
从消息中查找下一行,但是由于消息已被使用,因此将引发以下异常:
NoSuchElementException - if no line was found
因此,在阅读下一行之前,您需要确保要阅读下一行。您可以使用
hasNextLine()
方法,如果存在下一行,则返回true,否则返回false。
if(input.hasNextLine()) {
message = input.nextLine(); // read the next line
} else {
break; // exit the loop because, nothing to read left
}