我正在尝试创建一个客户端/服务器应用程序。问题是客户端的确认按钮在第一次输入时有效，但如果我为另一个输入点击相同的按钮，客户端 GUI 将冻结。
为什么 GUI 冻结？
客户：
public class ClientGui
{
private JFrame frmBookPointOf;
private JTextField txtRm;
private JTextArea txtrBookDetails;
private JTextField textField;
private JTextField textField_1;
private JTextField textField_2;
private JTextField textField_3;
private JTextField textField_4;
private JTextField textField_5;
private JComboBox comboBox_1;
private JComboBox comboBox;
private dbController dbCtrl;
private Connection conn;
private static Socket client;
private static BufferedReader fromServer = null;
private static DataOutputStream toServer = null;
/**
* Launch the application.
*/
public static void main(String[] args) {
try {
client = new Socket("127.0.0.1", 9090);
toServer =
new DataOutputStream(client.getOutputStream());
fromServer = new BufferedReader(
new InputStreamReader(client.getInputStream()));
String answer = fromServer.readLine();
JOptionPane.showMessageDialog(null, "Connected!\n" + answer, "Status", JOptionPane.INFORMATION_MESSAGE);
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
JOptionPane.showMessageDialog(null, e, "Error!", JOptionPane.ERROR_MESSAGE);
System.exit(0);
} catch (IOException e) {
// TODO Auto-generated catch block
JOptionPane.showMessageDialog(null, e, "Error!", JOptionPane.ERROR_MESSAGE);
System.exit(0);
}
EventQueue.invokeLater(new Runnable()
{
public void run() {
try {
ClientGui window = new ClientGui();
window.frmBookPointOf.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
/**
*
*/
public ClientGui()
{
frmBookPointOf = new JFrame();
frmBookPointOf.setTitle("Book Point of Sales");
frmBookPointOf.setBounds(100, 100, 850, 500);
frmBookPointOf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLabel lblIsbn = new JLabel("ISBN:");
String[] index = {"--Select ISBN--"};
comboBox = new JComboBox(index);
comboBox.setToolTipText("");
dbCtrl = new dbController();
try {
conn = dbCtrl.getConnection();
String sql = "select isbn from book";
PreparedStatement ps = conn.prepareStatement(sql);
ResultSet result = ps.executeQuery();
while (result.next())
{
comboBox.addItem(result.getString("isbn"));
}
conn.close();
} catch (Exception e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
JLabel lblNewLabel = new JLabel("Price:");
JLabel lblNewLabel_1 = new JLabel("Quantity:");
JLabel lblNewLabel_2 = new JLabel("Discount:");
txtRm = new JTextField();
txtRm.setEditable(false);
txtRm.setColumns(10);
comboBox.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e) {
try {
conn = dbCtrl.getConnection();
String x = comboBox.getSelectedItem().toString();
String sql = "select price from book where isbn= '"+x+"'";
PreparedStatement ps = conn.prepareStatement(sql);
ResultSet result = ps.executeQuery();
StringBuilder strBuilder = new StringBuilder();
while (result.next())
{
strBuilder.append(result.getString(1));
}
txtRm.setText(strBuilder.toString());
conn.close();
} catch (Exception e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
});
textField = new JTextField();
textField.setColumns(10);
comboBox_1 = new JComboBox();
comboBox_1.addItem("0");
comboBox_1.addItem("5");
comboBox_1.addItem("10");
comboBox_1.addItem("20");
comboBox_1.addItem("30");
JButton btnNewButton = new JButton("Clear");
btnNewButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e) {
txtRm.setText(null);
txtrBookDetails.setText(null);
textField.setText(null);
comboBox.setSelectedIndex(0);
comboBox_1.setSelectedIndex(0);
}
});
JButton btnNewButton_1 = new JButton("Confirm");
btnNewButton_1.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
Confirm();
}
});
JLabel lblNewLabel_3 = new JLabel("Sub Total:");
JLabel lblTotalItem = new JLabel("Total Item:");
JLabel lblTotalPrice = new JLabel("Total Price:");
JLabel lblP = new JLabel("Cash:");
JLabel lblNewLabel_4 = new JLabel("Remainder:");
textField_1 = new JTextField();
textField_1.setEditable(false);
textField_1.setColumns(10);
textField_2 = new JTextField();
textField_2.setEditable(false);
textField_2.setColumns(10);
textField_3 = new JTextField();
textField_3.setEditable(false);
textField_3.setColumns(10);
textField_4 = new JTextField();
textField_4.setColumns(10);
textField_5 = new JTextField();
textField_5.setEditable(false);
textField_5.setColumns(10);
JButton btnNewButton_2 = new JButton("Cash");
btnNewButton_2.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
Clear();
}
});
JButton btnPrintReceipt = new JButton("Print Receipt");
JLabel lblBookDetails = new JLabel("Book Details");
txtrBookDetails = new JTextArea();
txtrBookDetails.setLineWrap(true);
txtrBookDetails.setWrapStyleWord(true);
txtrBookDetails.setEditable(false);
comboBox.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e) {
try {
conn = dbCtrl.getConnection();
String y = comboBox.getSelectedItem().toString();
String sql = "select book_title,author,numPages from book where isbn= '"+y+"'";
PreparedStatement ps = conn.prepareStatement(sql);
ResultSet result = ps.executeQuery();
StringBuilder strBuilder = new StringBuilder();
while (result.next())
{
strBuilder.append("Title: ");
strBuilder.append(result.getString(1));
strBuilder.append("\nAuthor: ");
strBuilder.append(result.getString(2));
strBuilder.append("\nNumber of Pages: ");
strBuilder.append(result.getString(3));
}
txtrBookDetails.setText(strBuilder.toString());
conn.close();
} catch (Exception e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
});
JLabel lblSalesDetails = new JLabel("Sales Details");
JTextArea txtrSalesDetails = new JTextArea();
txtrSalesDetails.setLineWrap(true);
txtrSalesDetails.setEditable(false);
txtrSalesDetails.setWrapStyleWord(true);
GroupLayout groupLayout = new GroupLayout(frmBookPointOf.getContentPane());
groupLayout.setHorizontalGroup(
groupLayout.createParallelGroup(Alignment.LEADING)
.addGroup(groupLayout.createSequentialGroup()
.addContainerGap()
.addGroup(groupLayout.createParallelGroup(Alignment.LEADING)
.addGroup(groupLayout.createSequentialGroup()
.addGap(121)
.addComponent(btnNewButton, GroupLayout.PREFERRED_SIZE, 77, GroupLayout.PREFERRED_SIZE)
.addPreferredGap(ComponentPlacement.UNRELATED)
.addComponent(btnNewButton_1, GroupLayout.PREFERRED_SIZE, 80, GroupLayout.PREFERRED_SIZE))
.addGroup(groupLayout.createSequentialGroup()
.addGroup(groupLayout.createParallelGroup(Alignment.LEADING)
.addComponent(lblNewLabel_1)
.addComponent(lblNewLabel)
.addComponent(lblIsbn)
.addComponent(lblNewLabel_2))
.addGap(69)
.addGroup(groupLayout.createParallelGroup(Alignment.LEADING, false)
.addComponent(txtRm)
.addComponent(comboBox, GroupLayout.PREFERRED_SIZE, 201, GroupLayout.PREFERRED_SIZE)
.addComponent(comboBox_1, 0, 200, Short.MAX_VALUE)
.addComponent(textField)
.addComponent(textField_1, GroupLayout.DEFAULT_SIZE, 201, Short.MAX_VALUE)
.addComponent(textField_2, GroupLayout.DEFAULT_SIZE, 201, Short.MAX_VALUE)
.addComponent(textField_3, GroupLayout.DEFAULT_SIZE, 201, Short.MAX_VALUE)
.addComponent(textField_4, GroupLayout.DEFAULT_SIZE, 201, Short.MAX_VALUE)
.addComponent(textField_5, GroupLayout.DEFAULT_SIZE, 201, Short.MAX_VALUE)
.addGroup(groupLayout.createSequentialGroup()
.addComponent(btnNewButton_2)
.addPreferredGap(ComponentPlacement.UNRELATED)
.addComponent(btnPrintReceipt))))
.addComponent(lblNewLabel_3)
.addComponent(lblTotalItem)
.addComponent(lblTotalPrice)
.addComponent(lblP)
.addComponent(lblNewLabel_4))
.addGap(43)
.addGroup(groupLayout.createParallelGroup(Alignment.LEADING, false)
.addGroup(groupLayout.createSequentialGroup()
.addGroup(groupLayout.createParallelGroup(Alignment.LEADING)
.addComponent(lblSalesDetails)
.addComponent(lblBookDetails))
.addGap(251))
.addComponent(txtrSalesDetails, GroupLayout.DEFAULT_SIZE, 412, Short.MAX_VALUE)
.addComponent(txtrBookDetails))
.addContainerGap(33, Short.MAX_VALUE))
);
groupLayout.setVerticalGroup(
groupLayout.createParallelGroup(Alignment.LEADING)
.addGroup(groupLayout.createSequentialGroup()
.addGap(23)
.addGroup(groupLayout.createParallelGroup(Alignment.BASELINE)
.addComponent(comboBox, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
.addComponent(lblIsbn)
.addComponent(lblBookDetails))
.addGroup(groupLayout.createParallelGroup(Alignment.LEADING)
.addGroup(groupLayout.createSequentialGroup()
.addGap(18)
.addGroup(groupLayout.createParallelGroup(Alignment.BASELINE)
.addComponent(txtRm, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
.addComponent(lblNewLabel))
.addGap(18)
.addGroup(groupLayout.createParallelGroup(Alignment.BASELINE)
.addComponent(textField, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
.addComponent(lblNewLabel_1))
.addGap(18)
.addGroup(groupLayout.createParallelGroup(Alignment.BASELINE)
.addComponent(comboBox_1, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
.addComponent(lblNewLabel_2))
.addPreferredGap(ComponentPlacement.UNRELATED)
.addGroup(groupLayout.createParallelGroup(Alignment.BASELINE)
.addComponent(btnNewButton_1)
.addComponent(btnNewButton)))
.addGroup(groupLayout.createSequentialGroup()
.addPreferredGap(ComponentPlacement.RELATED)
.addComponent(txtrBookDetails, GroupLayout.PREFERRED_SIZE, 142, GroupLayout.PREFERRED_SIZE)))
.addGap(18)
.addGroup(groupLayout.createParallelGroup(Alignment.BASELINE)
.addComponent(lblNewLabel_3)
.addComponent(textField_1, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
.addComponent(lblSalesDetails))
.addPreferredGap(ComponentPlacement.UNRELATED)
.addGroup(groupLayout.createParallelGroup(Alignment.TRAILING, false)
.addComponent(txtrSalesDetails, Alignment.LEADING)
.addGroup(Alignment.LEADING, groupLayout.createSequentialGroup()
.addGap(7)
.addGroup(groupLayout.createParallelGroup(Alignment.BASELINE)
.addComponent(lblTotalItem)
.addComponent(textField_2, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE))
.addGap(18)
.addGroup(groupLayout.createParallelGroup(Alignment.BASELINE)
.addComponent(lblTotalPrice)
.addComponent(textField_3, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE))
.addGap(18)
.addGroup(groupLayout.createParallelGroup(Alignment.BASELINE)
.addComponent(lblP)
.addComponent(textField_4, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE))
.addGap(18)
.addGroup(groupLayout.createParallelGroup(Alignment.BASELINE)
.addComponent(lblNewLabel_4)
.addComponent(textField_5, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE))
.addPreferredGap(ComponentPlacement.UNRELATED)
.addGroup(groupLayout.createParallelGroup(Alignment.BASELINE)
.addComponent(btnNewButton_2)
.addComponent(btnPrintReceipt))))
.addContainerGap(89, Short.MAX_VALUE))
);
frmBookPointOf.getContentPane().setLayout(groupLayout);
}
public void Confirm()
{
float numb = 0f;
int numb1 = 0;
int numb2 = 0;
int numb3 = 0;
float numb4 = 0f;
String numbSub = null;
String numbIte = null;
String numbTot = null;
try
{
numb = Float.parseFloat(txtRm.getText());
numb1 = Integer.parseInt(textField.getText());
numb2 = Integer.parseInt(comboBox_1.getSelectedItem().toString());
numb3 = Integer.parseInt(textField_2.getText());
numb4 = Float.parseFloat(textField_3.getText());
}
catch (NumberFormatException ex)
{}
try
{
toServer.writeFloat(numb);
toServer.writeInt(numb1);
toServer.writeInt(numb2);
toServer.writeInt(numb3);
toServer.writeFloat(numb4);
}catch (IOException e1)
{
// TODO Auto-generated catch block
e1.printStackTrace();
}
try
{
numbSub = fromServer.readLine();
numbIte = fromServer.readLine();
numbTot = fromServer.readLine();
} catch (IOException e1)
{
e1.printStackTrace();
}
textField_1.setText(numbSub);
textField_2.setText(numbIte);
textField_3.setText(numbTot);
txtRm.setText(null);
txtrBookDetails.setText(null);
textField.setText(null);
comboBox.setSelectedIndex(0);
comboBox_1.setSelectedIndex(0);
}
public void Clear()
{
float numb5 = 0f;
float numb6 = 0f;
String numbRem = null;
try
{
numb5 = Float.parseFloat(textField_3.getText());
numb6 = Float.parseFloat(textField_4.getText());
}catch (NumberFormatException ex)
{
System.out.println(ex);
}
try
{
toServer.writeFloat(numb5);
toServer.writeFloat(numb6);
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try
{
numbRem = fromServer.readLine();
}catch (IOException ex)
{
ex.printStackTrace();
}
textField_5.setText(numbRem);
}
}
服务器：
public class ServerGui{
private JFrame frmBookServer;
private static ServerSocket listener;
private static Socket socket;
private dbController dbCtrl;
private Connection conn;
/**
* Launch the application.
*/
public static void main(String[] args) throws IOException
{
listener = new ServerSocket(9090);
EventQueue.invokeLater(new Runnable()
{
public void run()
{
try {
ServerGui window = new ServerGui();
window.frmBookServer.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*
*/
public ServerGui()
{
frmBookServer = new JFrame();
frmBookServer.setTitle("Book Server");
frmBookServer.setBounds(100, 100, 800, 600);
frmBookServer.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JButton btnNewButton = new JButton("Start Server");
JButton btnNewButton_1 = new JButton("Stop Server");
JButton btnNewButton_2 = new JButton("Display Sales");
final JTextArea txtrDetailsOfRequest = new JTextArea();
txtrDetailsOfRequest.setEditable(false);
txtrDetailsOfRequest.setWrapStyleWord(true);
GroupLayout groupLayout = new GroupLayout(frmBookServer.getContentPane());
groupLayout.setHorizontalGroup(
groupLayout.createParallelGroup(Alignment.LEADING)
.addGroup(groupLayout.createSequentialGroup()
.addContainerGap()
.addGroup(groupLayout.createParallelGroup(Alignment.LEADING)
.addGroup(groupLayout.createSequentialGroup()
.addGap(10)
.addComponent(txtrDetailsOfRequest, GroupLayout.PREFERRED_SIZE, 742, GroupLayout.PREFERRED_SIZE))
.addGroup(groupLayout.createSequentialGroup()
.addComponent(btnNewButton)
.addGap(18)
.addComponent(btnNewButton_1)
.addGap(18)
.addComponent(btnNewButton_2)))
.addGap(22))
);
groupLayout.setVerticalGroup(
groupLayout.createParallelGroup(Alignment.LEADING)
.addGroup(groupLayout.createSequentialGroup()
.addContainerGap()
.addGroup(groupLayout.createParallelGroup(Alignment.BASELINE)
.addComponent(btnNewButton)
.addComponent(btnNewButton_1)
.addComponent(btnNewButton_2))
.addPreferredGap(ComponentPlacement.UNRELATED)
.addComponent(txtrDetailsOfRequest, GroupLayout.PREFERRED_SIZE, 497, GroupLayout.PREFERRED_SIZE)
.addContainerGap(20, Short.MAX_VALUE))
);
frmBookServer.getContentPane().setLayout(groupLayout);
btnNewButton.addActionListener(new ActionListener()
{
@Override
public void actionPerformed(ActionEvent e)
{
txtrDetailsOfRequest.setText("Starting Server....");
Thread t = new Thread() {
@Override
public void run()
{
try
{
while(true)
{
socket = listener.accept();
PrintWriter toClient = new PrintWriter(socket.getOutputStream(), true);
toClient.println(new Date().toString());
ServerCalc();
}
}catch (IOException e1)
{
// TODO Auto-generated catch block
e1.printStackTrace();
}
try
{
sleep(10); // milliseconds
}catch (InterruptedException ex) {}
}
};
t.start();
}
});
btnNewButton_1.addActionListener(new ActionListener()
{
@Override
public void actionPerformed(ActionEvent e)
{
txtrDetailsOfRequest.setText("Closing Server....");
try
{
listener.close();
} catch (IOException e1)
{
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
});
btnNewButton_2.addActionListener(new ActionListener()
{
@Override
public void actionPerformed(ActionEvent e)
{
dbCtrl = new dbController();
try {
conn = dbCtrl.getConnection();
String sql = "select book_title,quantity from sales";
PreparedStatement ps = conn.prepareStatement(sql);
ResultSet result = ps.executeQuery();
StringBuilder strBuilder = new StringBuilder();
while (result.next())
{
strBuilder.append(result.getString(1)).append(" = ").append(result.getString(2));
strBuilder.append("\n");
}
txtrDetailsOfRequest.setText(strBuilder.toString());
conn.close();
} catch (Exception e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
});
}
public void ServerCalc()
{
try{
PrintWriter toClient = new PrintWriter(socket.getOutputStream(), true);
DataInputStream fromClient = new DataInputStream(socket.getInputStream());
//calculate sub total, total item, total price
float numb = fromClient.readFloat();
int numb1 = fromClient.readInt();
int numb2 = fromClient.readInt();
int numb3 = fromClient.readInt();
float numb4 = fromClient.readFloat();
float dis = (float) (numb2 * 0.01);
float numbSub =numb - ((dis) * numb);
float numbTot =(numbSub * numb1) + numb4;
int numbIte = numb1 + numb3;
toClient.println(numbSub);
toClient.println(numbIte);
toClient.println(numbTot);
//calculate cash remainder
float numb5 = fromClient.readFloat();
float numb6 = fromClient.readFloat();
float numbRem = numb6 - numb5;
toClient.println(numbRem);
}catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
}