我正在尝试构建一个LAN通信软件，其中进程应该是这样的，当用户登录时，客户端和服务器之间的网络应该启动。
我面临的问题是每当我在按钮的addactionlistener中放入我的startRunning（）（这是启动网络的方法）方法时，整个软件会冻结，但如果我把方法放在addactionlistener之外的话开始很好。问题出现在btnNewButton.addActionListener中。如果计数为1，那么它应该调用startrunning（）方法，它不会使整个软件冻结。
从startRunning（）方法开始到下面的每个方法都工作正常。数据库还能够检查给定的用户名和密码是否正确。当startRunning方法在构造函数中但不在btnNewButton.addActionListener中时，此软件运行良好。
public class Server extends JFrame {
private JTextField userText;
private JTextArea chatWindow;
private ObjectOutputStream output;
private ObjectInputStream input;
private ServerSocket server;
private Socket connection;
Connection dbconnection = null;
private JTextField textField_1;
private JPasswordField passwordField_1;
public Server() {
super("Communication system");
dbconnection = sqliteConnection.dbConnector();
setupFrame();
}
private void setupFrame() {
setBounds(100, 100, 450, 300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
getContentPane().setLayout(null);
JLabel lblNewLabel = new JLabel("UserName");
lblNewLabel.setBounds(10, 11, 81, 14);
getContentPane().add(lblNewLabel);
JLabel lblNewLabel_1 = new JLabel("Password");
lblNewLabel_1.setBounds(10, 36, 59, 14);
getContentPane().add(lblNewLabel_1);
JButton btnNewButton = new JButton("Login");
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
try {
String query = "SELECT * FROM EmplyeeInfo WHERE Username=? and password=?";
PreparedStatement pst = dbconnection
.prepareStatement(query);
pst.setString(1, textField_1.getText());
pst.setString(2, passwordField_1.getText());
ResultSet rs = pst.executeQuery();
int count = 0;
while (rs.next()) {
count++;
}
if (count == 1) {
textField_1.setText("");
passwordField_1.setText("");
JOptionPane.showMessageDialog(null,
"Correct Username and Password");
startRunning();
} else {
textField_1.setText("");
passwordField_1.setText("");
JOptionPane.showMessageDialog(null, "Wrong try again");
}
rs.close();
pst.close();
} catch (Exception e) {
// TODO: handle exception
JOptionPane.showMessageDialog(null, e);
}
}
});
btnNewButton.setBounds(335, 7, 89, 23);
getContentPane().add(btnNewButton);
textField_1 = new JTextField();
textField_1.setBounds(101, 8, 224, 20);
getContentPane().add(textField_1);
passwordField_1 = new JPasswordField();
passwordField_1.setBounds(101, 33, 224, 20);
getContentPane().add(passwordField_1);
userText = new JTextField();
userText.setBounds(10, 230, 330, 20);
userText.setEditable(false);
userText.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent event) {
// TODO Auto-generated method stub
sendMessage(event.getActionCommand());
userText.setText("");
}
});
getContentPane().add(userText);
userText.setColumns(10);
chatWindow = new JTextArea();
chatWindow.setBounds(10, 75, 330, 144);
getContentPane().add(chatWindow);
setVisible(true);
}
// set up and run the server
public void startRunning() {
try {
server = new ServerSocket(6789, 100);
while (true) {
try {
waitForConnection();
setupStreams();
whileChatting();
} catch (EOFException eofException) {
// TODO: handle exception
showMessage("\nServer Ended the conection!");
} finally {
closeCrap();
}
}
} catch (IOException ioException) {
ioException.printStackTrace();
}
}
// wait for the connection, then display connection
private void waitForConnection() throws IOException {
showMessage("Waiting for someone to connect... \n");
connection = server.accept();
showMessage(" Now connected to "
+ connection.getInetAddress().getHostName());
}
// get stream to send and receive data
private void setupStreams() throws IOException {
output = new ObjectOutputStream(connection.getOutputStream());
output.flush();
input = new ObjectInputStream(connection.getInputStream());
showMessage("\n Streams are now Setup \n");
}
// during the chat conversation
private void whileChatting() throws IOException {
String message = " You are now connected";
sendMessage(message);
ableToType(true);
do {
// have a conversation
try {
message = (String) input.readObject();
showMessage("\n" + message);
} catch (ClassNotFoundException classNotFoundException) {
showMessage("\n I don't know what the user send");
}
} while (!message.equals("CLIENT - END"));
}
// closing the streams and sockets after done chatting
private void closeCrap() {
showMessage("\n closing connections...\n");
ableToType(false);
try {
output.close();
input.close();
connection.close();
} catch (IOException ioException) {
ioException.printStackTrace();
}
}
// send message to a client
private void sendMessage(String message) {
try {
output.writeObject("SERVER - " + message);
output.flush();
showMessage("\nSERVER -" + message);
} catch (IOException ioException) {
chatWindow.append("\n Error : can't send the message");
}
}
// updates chat window
private void showMessage(final String text) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
chatWindow.append("" + text);
}
});
}
// allowing user to type stuff in the box
private void ableToType(final boolean tof) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
userText.setEditable(tof);
}
});
}
}
答案 0 :(得分：1)
您可能必须将其置于不同的线程中 - 您可以将线程本地化以仅包含startRunning方法或您想要的内容：
public void actionPerformed(ActionEvent arg0) {
Thread th=new Thread() {
public void run() {
try {
String query = "SELECT * FROM EmplyeeInfo WHERE Username=? and password=?";
PreparedStatement pst = dbconnection
.prepareStatement(query);
pst.setString(1, textField_1.getText());
pst.setString(2, passwordField_1.getText());
ResultSet rs = pst.executeQuery();
int count = 0;
while (rs.next()) {
count++;
}
if (count == 1) {
textField_1.setText("");
passwordField_1.setText("");
JOptionPane.showMessageDialog(null,
"Correct Username and Password");
startRunning();
} else {
textField_1.setText("");
passwordField_1.setText("");
JOptionPane.showMessageDialog(null, "Wrong try again");
}
rs.close();
pst.close();
} catch (Exception e) {
// TODO: handle exception
JOptionPane.showMessageDialog(null, e);
}
}
};
th.start();
});