我知道有很多关于JTable没有显示的问题，但我找不到任何与我当前问题有关的问题。我正在使用JCreator Pro作为数据库进行IDE和MS访问。这是我的代码。
import javax.swing.*;
import javax.swing.table.*;
import java.awt.event.*;
import java.awt.*;
import java.io.*;
import java.sql.*;
import java.util.*;
public class JCashiering extends JFrame implements ActionListener,FocusListener {
Container c;
JLabel lblProductCode,lblProductName,lblUnit,lblPrice,lblQuantity,lblAmountTendered,lblTotalAmountDue,lblPayment,lblChange,lblFind;
JTextField txtProductCode,txtProductName,txtPrice,txtQuantity,txtAmountTendered,txtTotalAmountDue,txtPayment,txtChange,txtFind,txtUnit;
JTable dgvProductInformation;
JPanel buttonPanel;
JButton btnFind,btnAdd,btnRemove,btnProceed,btnCancel,btnExit;
JScrollPane scrollPane;
Vector columnNames;
Vector data;
static Connection con;
static ResultSet rs;
static Statement stmt;
static int Quantity=0;
static double Change=0.0;
public JCashiering() {
c=getContentPane();
setLayout(null);
//addlbl
add(lblProductCode = new JLabel("Product Code:"));
add(lblProductName = new JLabel("Product Name:"));
add(lblUnit = new JLabel("Unit:"));
add(lblPrice = new JLabel("Price:"));
add(lblQuantity = new JLabel("Quantity:"));
add(lblAmountTendered = new JLabel("Amount tendered:"));
add(lblTotalAmountDue = new JLabel("Total amout due:"));
add(lblPayment = new JLabel("Payment:"));
add(lblChange = new JLabel("Change:"));
//setboundslbl1st
lblProductCode.setBounds(20,250,100,50);
lblProductName.setBounds(20,280,100,50);
lblUnit.setBounds(20,310,100,50);
lblPrice.setBounds(20,340,100,50);
lblQuantity.setBounds(20,370,100,50);
//setboundslbl2nd
lblAmountTendered.setBounds(300,250,130,50);
lblTotalAmountDue.setBounds(300,280,120,50);
lblPayment.setBounds(300,310,100,50);
lblChange.setBounds(300,340,100,50);
//addtxt
add(txtProductCode=new JTextField());
add(txtProductName=new JTextField());
add(txtPrice=new JTextField());
add(txtUnit=new JTextField());
add(txtQuantity =new JTextField());
add(txtAmountTendered = new JTextField());
add(txtTotalAmountDue = new JTextField());
add(txtPayment = new JTextField());
add(txtChange = new JTextField());
//settxt&cbo1st
txtProductCode.setBounds(110,265,150,20);
txtProductName.setBounds(110,295,150,20);
txtUnit.setBounds(110,325,150,20);
txtPrice.setBounds(110,355,150,20);
txtQuantity.setBounds(110,385,150,20);
//settxt2nd
txtAmountTendered.setBounds(410,265,150,20);
txtTotalAmountDue.setBounds(410,295,150,20);
txtPayment.setBounds(410,325,150,20);
txtChange.setBounds(410,355,150,20);
//btnadd
add(btnAdd = new JButton("Add to cart"));
add(btnFind = new JButton("Find"));
add(btnRemove = new JButton("Remove"));
add(btnProceed = new JButton("Proceed"));
add(btnCancel = new JButton("Cancel"));
add(btnExit = new JButton("Exit"));
//find
add(lblFind = new JLabel("Find:"));
lblFind.setBounds(20,230,150,20);
add(txtFind = new JTextField());
txtFind.setBounds(60,230,500,20);
//btnset
btnAdd.setBounds(110,420,100,25);
btnAdd.addActionListener(this);
btnRemove.setBounds(110,450,100,25);
btnRemove.addActionListener(this);
btnProceed.setBounds(410,385,150,25);
btnProceed.addActionListener(this);
btnCancel.setBounds(300,420,100,25);
btnCancel.addActionListener(this);
btnExit.setBounds(300,450,100,25);
btnExit.addActionListener(this);
//focuslistener
txtQuantity.addFocusListener(this);
txtPayment.addFocusListener(this);
//findlistener
txtFind.addActionListener(this);
//Disablebtns
setDisabled(txtProductCode,txtPrice,txtAmountTendered,txtTotalAmountDue,txtChange,txtUnit,txtProductName);
//dgv
columnNames = new Vector();
data = new Vector();
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection connect =DriverManager.getConnection("jdbc:odbc:dbCashiering");
String sql = "Select * from tblProduct";
Statement stmt = connect.createStatement();
ResultSet rs = stmt.executeQuery( sql );
ResultSetMetaData md = rs.getMetaData();
int columns = md.getColumnCount();
for (int i = 1; i <= columns; i++) {
columnNames.addElement( md.getColumnName(i) );
}
while (rs.next()) {
Vector row = new Vector(columns);
for (int i = 1; i <= columns; i++) {
row.addElement( rs.getObject(i) );
}
data.addElement( row );
}
rs.close();
stmt.close();
}
catch(Exception e) {
JOptionPane.showMessageDialog(null,"Connection failed!");
}
//adddgv
add(dgvProductInformation =new JTable(data, columnNames));
dgvProductInformation.setBounds(20,20,545,200);
add(scrollPane = new JScrollPane( dgvProductInformation ));
add(buttonPanel = new JPanel());
//frm
setSize(600,600);
setVisible(true);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
//connection method
/*public static void connect(){
try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
con = DriverManager.getConnection("jdbc:odbc:dbCashiering");
stmt = con.createStatement();
//JOptionPane.showMessageDialog(null,"Connection successful!");
}
catch(Exception ex){
JOptionPane.showMessageDialog(null,"Connection failed!");
}
}*/
//event
//actionEventdgv
public void actionPerformed(ActionEvent e){
if(e.getSource()==btnExit){
System.exit(0);
}
if(e.getSource()==btnCancel){
Clear(txtProductCode,txtProductName,txtPrice,txtQuantity,txtAmountTendered,txtTotalAmountDue,txtPayment,txtChange,txtFind,txtUnit);
}
//Event for Find
if(e.getSource()==txtFind){
//find action here
JOptionPane.showMessageDialog(null,"wow");
}
}
//focusEvent
public void focusGained(FocusEvent f){
}
public void focusLost(FocusEvent f){
//validation for field empty
if(f.getSource()==txtQuantity){
if(isEmpty(txtQuantity));
}
if(f.getSource()==txtPayment){
if(isEmpty(txtQuantity));
}
//validation for correct format
if(f.getSource()==txtQuantity){
if(isCorrectFormat(txtQuantity)==false);
}
if(f.getSource()==txtPayment){
if(isCorrectFormat(txtPayment)==false);
}
}
//main
public static void main(String[] args) {
//connect();
new JCashiering();
}
//method
public static void setDisabled(JTextField txt1,JTextField txt2,JTextField txt3,JTextField txt4,
JTextField txt5,JTextField txt6,JTextField txt7){
txt1.setEnabled(false);
txt2.setEnabled(false);
txt3.setEnabled(false);
txt4.setEnabled(false);
txt5.setEnabled(false);
txt6.setEnabled(false);
txt7.setEnabled(false);
}
public static void Clear(JTextField txt1,JTextField txt2,JTextField txt3,JTextField txt4,
JTextField txt5,JTextField txt6,JTextField txt7,JTextField txt8,JTextField txt9,JTextField txt10){
txt1.setText("");
txt2.setText("");
txt3.setText("");
txt4.setText("");
txt5.setText("");
txt6.setText("");
txt7.setText("");
txt8.setText("");
txt9.setText("");
txt10.setText("");
}
public static boolean isEmpty(JTextField txt){
if(txt.getText().trim().length()==0){
JOptionPane.showMessageDialog(null,"Field cannot be empty!");
txt.requestFocus(true);
return true;
}
else return false;
}
public static boolean isCorrectFormat(JTextField txt){
char temp= ' ';
for(int i=0;i<txt.getText().length();i++){
temp=txt.getText().charAt(i);
if(Character.isDigit(temp)){
return true;
}
else{
JOptionPane.showMessageDialog(null,"Invalid number format!");
txt.requestFocus(true);
}
return false;
}
return true;
}
}
答案 0 :(得分：2)
你的问题是关于一张桌子。发布的代码中有95％与表格无关。
我们对您的计划的核心转储不感兴趣。当你作为一个问题发布一个适当的SSCCE来证明问题，因为我们没有时间阅读与问题无关的数百行代码。
dgvProductInformation.setBounds(20,20,545,200);
add(scrollPane = new JScrollPane( dgvProductInformation ));
作为一个狂野的问题我会说问题是你永远不会设置滚动窗格的界限。设置表的边界不起作用，因为滚动窗格使用自己的布局管理器。
不要使用空布局！不要使用setBounds（）!!!
使用布局管理器。 Swing旨在与布局管理器一起使用，因此您不必担心设置组件的大小和位置。了解如何正确使用Swing。