在数据库和表中插入一行？

Question

public class GetData 
{
Object[][] MyArray=null;
String [] AttributeNames;
Connection connect;
Statement statement;
String state;
int NumberOfRows,NumberOfColumns;
JTable TableData = new JTable ();
DefaultTableModel model = (DefaultTableModel) TableData.getModel();
public void GetData(JFrame Frame)
{
    connection();
    initComponents(Frame);
    Data();
    TableWidth();
    TableData.setVisible(true);
}
public void TableWidth ()
{
    TableColumn column = null;
    for (int i = 0; i < NumberOfColumns; i++) 
    {
        column = TableData.getColumnModel().getColumn(i);
        if (i == 7) {
            column.setPreferredWidth(350); 
                    }
        if (i == 0) {
            column.setPreferredWidth(25);
                    }
        if (i == 1) {
            column.setPreferredWidth(50);
                    }
        if (i == 3) {
            column.setPreferredWidth(30);
                    }
        if (i == 4) {
            column.setPreferredWidth(35);
                    }
        if (i == 5) {
            column.setPreferredWidth(50);
                    }
    }
}
public void Data () 
{
    try {
        ResultSet res = statement.executeQuery("SELECT * FROM nhanvien");
        ResultSetMetaData RSMD = res.getMetaData();
        NumberOfColumns = RSMD.getColumnCount();
        AttributeNames = new String[NumberOfColumns];
        for(int i=0;i<NumberOfColumns;i++)
            AttributeNames[i]=RSMD.getColumnName(i+1);
        MyArray=new Object[500][NumberOfColumns];
        int R=0;
        while(res.next()) {
            for(int C=1; C<=NumberOfColumns;C++)
                MyArray[R][C-1]=res.getObject(C);
            R++;
        }         
        NumberOfRows=R;
        Object[][] TempArray=MyArray;
        MyArray=new Object[NumberOfRows][NumberOfColumns];
        for(R=0;R<NumberOfRows;R++)
            for(int C=0;C<NumberOfColumns;C++)
                MyArray[R][C]=TempArray[R][C];
        TableData.setModel(new MyTableModel());
        TableData.setVisible(true);
    }      
    catch(Exception e) {}
}
public void initComponents(JFrame f) 
{    
    model = new DefaultTableModel (new Object [][] 
        {
            {null},
            {null},
            {null},
            {null}
        },
        new String [] {""}
        ) {
          Class[] types = new Class [] {java.lang.Object.class};
          boolean[]canEdit=new boolean[]{false};

          public Class getColumnClass(int columnIndex) 
          {
                return types [columnIndex];
          }
          public boolean isCellEditable(int rowIndex, int columnIndex) 
          {
                return canEdit [columnIndex];
          }
    };
    TableData.setModel(model);
    JScrollPane ScrollPane1 = new JScrollPane(TableData); 
    ScrollPane1.setBounds(30,170,950,290);
    f.add(ScrollPane1,BorderLayout.CENTER);
    TableData.setVisible(true);
}
public class MyTableModel extends AbstractTableModel 
{  
    public int getColumnCount() 
    {
        return (NumberOfColumns);
    }
    public int getRowCount() 
    {
        return(NumberOfRows);
    }
    public String getColumnName(int i) 
    {
        return (AttributeNames[i]);
    }
    public java.lang.Object getValueAt(int row, int column) 
    {
        return(MyArray[row][column]);
    }     
}
public void connection ()
{
    try {
        Class.forName("org.gjt.mm.mysql.Driver");
        String url = "jdbc:mysql://localhost:3306/jdbc?      useUnicode=true&characterEncoding=UTF-8";
        connect = DriverManager.getConnection(url,"root","");
        statement = connect.createStatement();
    }
    catch(Exception e) {}
}
public static void main (String[] args)
{
    GetData GD = new GetData ();
}

}

这是我将数据库显示为JTable的代码

public void Add (JFrame F) throws SQLException
{          
    String MNV = TX1.getText();
    String HNV = TX2.getText();
    String TNV = TX3.getText();
    String GT = TX4.getText();
    String NS = TX5.getText();
    String TD = TX6.getText();
    String SDT = TX7.getText();
    String DC = TX8.getText();       
    AD.Add("INSERT INTO `nhanvien` "
    + "(`MÃ NV`, `HỌ NV`, `TÊN NV`, `GIỚI TÍNH`, `NĂM SINH`, `TRÌNH ĐỘ`, `SỐ   ĐT`, `ĐỊA CHỈ`)"
    + " VALUES ('"+MNV+"', '"+HNV+"', '"+TNV+"', '"+GT+"', '"+NS+"', '"+TD+"', '"+SDT+"', '"+DC+"');");
    GD.GetData(F);
}

这是我向Jtable和Database插入行的代码。 我的问题是有时我正常添加一行但有时当我点击按钮添加Jtable消失但值仍然添加到数据库和talbe，我必须关闭框架并再次打开所以我可以看到新的行。所以任何人都可以知道为什么会发生这种情况，并且无论如何都要向Jtable显示数据库（简单方法）。谢谢！