0
這是一個JDBC項目。來自WAMP服務器上的mySql數據庫的數據以jtable顯示。現在我想在我的Spinner按鈕上輸入用戶輸入的ID並刪除具有該ID的行。我做了一個SQL查詢並且一切正常，但是當我的查詢被執行時，myjtable上的數據不會刷新。我點擊我的JNazad按鈕（我的後退按鈕），並重新進入該窗口，以便我的Jtable顯示刷新數據。我想我還沒有在我的NapraviTablicu方法正確實施FireTableModel，但不知道我做錯了什麼：未顯示JTable刷新數據
public class GUIBDelete extends JFrame{
private SpinnerModel SM;
private JSpinner Spinner;
private JLabel LUnos;
private JButton BNazad, BIzvrsi;
private String ID, SqlQuery;
private Vector NaziviKolona = new Vector();
private Vector Podaci = new Vector();
private JTable Tablica=new JTable();
private JScrollPane ScrollPane;
private DefaultTableModel model;
private JTable NapraviTablicu(){
try {
String SqlQuery = "SELECT * FROM `nfc_baza`";
Podaci.clear();
NaziviKolona.clear();
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection con = DriverManager.getConnection("jdbc:mysql://"
+ "localhost:3306/nfc", "root", "");
Statement Stat = con.createStatement();
ResultSet Rez = Stat.executeQuery(SqlQuery);
ResultSetMetaData md = Rez.getMetaData();
int columns = md.getColumnCount();
for (int i = 1; i <= columns; i++) {
NaziviKolona.addElement(md.getColumnName(i));
}
while (Rez.next()) {
Vector red = new Vector(columns);
for (int i = 1; i <= columns; i++) {
red.addElement(Rez.getObject(i));
}
Podaci.addElement(red);
}
Rez.close();
Stat.close();
con.close();
} catch (Exception e) {
System.out.println(e);
}
model = new DefaultTableModel(Podaci, NaziviKolona);
model.fireTableDataChanged();
JTable table = new JTable(model);
return table;
}
ActionListener a1 = new ActionListener() {
public void actionPerformed(ActionEvent a) {
dispose();
new GUIIzbornik();
}
};
ActionListener a2 = new ActionListener() {
public void actionPerformed(ActionEvent a) {
ID=null;
SqlQuery = "DELETE FROM `nfc`.`nfc_baza` WHERE `nfc_baza`.`ID` = ";
IzvrsiQuery();
model.fireTableDataChanged();
}
private void IzvrsiQuery() {
Object sp = Spinner.getValue();
ID = sp.toString();
SqlQuery=SqlQuery+ID;
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
Connection con2 = DriverManager.getConnection(
"jdbc:mysql://" + "localhost:3306/nfc", "root", "");
Statement Stat = con2.createStatement();
int Rez = Stat.executeUpdate(SqlQuery);
Stat.close();
con2.close();
JOptionPane.showMessageDialog(null, "Uspješno izvrseno!",
"Poruka!", JOptionPane.INFORMATION_MESSAGE);
} catch (Exception e) {
System.out.println(e);
}
}
};
GUIBDelete(){
setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
Tablica=NapraviTablicu();
ScrollPane = new JScrollPane(Tablica);
c.fill = GridBagConstraints.BOTH;
c.insets = new Insets(2, 2, 2, 2);
c.weightx = 0.1;
c.weighty = 0.1;
c.gridwidth = 4;
c.gridheight = 2;
c.gridx = 0;
c.gridy = 0;
add(ScrollPane, c);
LUnos= new JLabel("<html><br>Unesite ID elementa</br> kojeg želite obrisati:<html>");
c.gridx = 0;
c.gridy = 2;
c.gridwidth = 1;
c.gridheight = 1;
add(LUnos, c);
SM = new SpinnerNumberModel(1, 1, 1000, 1);
Spinner = new JSpinner(SM);
c.gridx = 2;
c.gridy = 2;
c.gridwidth = 1;
add(Spinner, c);
BNazad = new JButton("Nazad");
c.gridx = 0;
c.gridy = 3;
c.gridwidth = 1;
BNazad.addActionListener(a1);
add(BNazad, c);
BIzvrsi = new JButton("Izvrši");
c.gridx = 3;
c.gridy = 3;
BIzvrsi.addActionListener(a2);
add(BIzvrsi, c);
setSize(400, 500);
setTitle("Brisanje podataka");
setVisible(true);
setLocationRelativeTo(null);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
GUIBDelete i = new GUIBDelete();
}
});
}
}
首先，非常感謝您的回答！
當我使用PreparedStatement我得到這個異常：
java.lang.ClassCastException: com.mysql.jdbc.StatementImpl cannot be
cast to java.sql.PreparedStatement
..所以我必須用經典Statement
而且我也試過不創建JTable每一次，我只是做模型在我NapraviTablicu方法，並稍後在我的構造函數中使用該模型，方法是將其簡單地添加到表Tablica，但現在表未顯示任何數據。我不知道如果我在代碼中實現你的提示正確的方式...
public class GUIBDelete extends JFrame{
private SpinnerModel SM;
private JSpinner Spinner;
private JLabel LUnos;
private JButton BNazad, BIzvrsi;
private String ID, SqlQuery;
private Vector NaziviKolona = new Vector();
private Vector Podaci = new Vector();
private JTable Tablica=new JTable();
private JScrollPane ScrollPane;
private DefaultTableModel model;
private void NapraviTablicu(){
try {
String SqlQuery = "SELECT * FROM `nfc_baza`";
Podaci.clear();
NaziviKolona.clear();
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection("jdbc:mysql://"
+ "localhost:3306/nfc", "root", "");
Statement Stat = con.createStatement();
ResultSet Rez = Stat.executeQuery(SqlQuery);
ResultSetMetaData md = Rez.getMetaData();
int columns = md.getColumnCount();
for (int i = 1; i <= columns; i++) {
NaziviKolona.addElement(md.getColumnName(i));
}
while (Rez.next()) {
Vector red = new Vector(columns);
for (int i = 1; i <= columns; i++) {
red.addElement(Rez.getObject(i));
}
Podaci.addElement(red);
}
Rez.close();
Stat.close();
con.close();
} catch (Exception e) {
System.out.println(e);
}
model = new DefaultTableModel(Podaci, NaziviKolona);
//model.fireTableDataChanged();
}
ActionListener a1 = new ActionListener() {
public void actionPerformed(ActionEvent a) {
dispose();
new GUIIzbornik();
}
};
ActionListener a2 = new ActionListener() {
public void actionPerformed(ActionEvent a) {
ID=null;
SqlQuery = "DELETE FROM `nfc`.`nfc_baza` WHERE `nfc_baza`.`ID` = ";
IzvrsiQuery();
//model.fireTableDataChanged();
}
private void IzvrsiQuery() {
Object sp = Spinner.getValue();
ID = sp.toString();
SqlQuery=SqlQuery+ID;
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con2 = DriverManager.getConnection(
"jdbc:mysql://" + "localhost:3306/nfc", "root", "");
PreparedStatement Stat = (PreparedStatement) con2.createStatement();
int Rez = Stat.executeUpdate(SqlQuery);
Stat.close();
con2.close();
JOptionPane.showMessageDialog(null, "Uspješno izvrseno!",
"Poruka!", JOptionPane.INFORMATION_MESSAGE);
} catch (Exception e) {
System.out.println(e);
}
}
};
GUIBDelete(){
setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
Tablica=new JTable(model);
ScrollPane = new JScrollPane(Tablica);
c.fill = GridBagConstraints.BOTH;
c.insets = new Insets(2, 2, 2, 2);
c.weightx = 0.1;
c.weighty = 0.1;
c.gridwidth = 4;
c.gridheight = 2;
c.gridx = 0;
c.gridy = 0;
add(ScrollPane, c);
LUnos= new JLabel("<html><br>Unesite ID elementa</br> kojeg želite obrisati:<html>");
c.gridx = 0;
c.gridy = 2;
c.gridwidth = 1;
c.gridheight = 1;
add(LUnos, c);
SM = new SpinnerNumberModel(1, 1, 1000, 1);
Spinner = new JSpinner(SM);
c.gridx = 2;
c.gridy = 2;
c.gridwidth = 1;
add(Spinner, c);
BNazad = new JButton("Nazad");
c.gridx = 0;
c.gridy = 3;
c.gridwidth = 1;
BNazad.addActionListener(a1);
add(BNazad, c);
BIzvrsi = new JButton("Izvrši");
c.gridx = 3;
c.gridy = 3;
BIzvrsi.addActionListener(a2);
add(BIzvrsi, c);
setSize(400, 500);
setTitle("Brisanje podataka");
setVisible(true);
setLocationRelativeTo(null);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
GUIBDelete i = new GUIBDelete();
}
});
}
}
請學習java命名約定並堅持使用它們。 – kleopatra 2013-03-02 14:29:05