[英]How to take backup of a single table in a MySQL database using Java swing?
[英]Using java swing table to update MySQL database values
該程序用於從數據庫讀取數據。 在數據庫中,有三個表pki17,pki18,pkn18。 為了查看不同的表,使用了JComboBox,它通過更改表的TableModel來工作。 同樣通過使用tableChanged方法,我使表格可編輯。 當表中的單元格值更改時,數據庫中的相應值也必須更改為。
當我同時使用tableChanged和actionPerformed方法時,當我在回轉表中編輯單元格時,數據庫中的值不會更改。 當我刪除actionPerformed方法時,可以通過編輯表格單元來更新數據庫。
我需要同時具備兩種能力,即使用JComboBox從數據庫中選擇一個表,並通過編輯Swing表中的值來更新數據庫值。
我認為存在問題是因為兩種方法都更改了表的TableModel。 但是我不知道如何解決。
public class TableCombobox extends JPanel implements ActionListener, TableModelListener {
static JTable table;
static JComboBox box;
static MyTableModel model;
static Connection con = null;
static Statement stmt = null;
public TableCombobox() throws SQLException {
super(new BorderLayout());
table = new JTable(new MyTableModel("pki18"));
table.setPreferredScrollableViewportSize(new Dimension(500, 400));
table.setFillsViewportHeight(true);
table.getModel().addTableModelListener(this);
JScrollPane scrollPane = new JScrollPane(table);
JPanel menuPanel = new JPanel();
menuPanel.setLayout(new BoxLayout(menuPanel, BoxLayout.Y_AXIS));
menuPanel.setBorder(BorderFactory.createMatteBorder(0, 0, 0, 1,
Color.black));
String[] dalykas = { "Chose groop", "pki17", "pki18", "pkn18" };
box = new JComboBox(dalykas);
box.setMaximumSize(new Dimension(150, 25));
box.setAlignmentX(Component.LEFT_ALIGNMENT);
box.addActionListener(this);
box.setSelectedIndex(2);
menuPanel.add(box);
JPanel cards = new JPanel(new CardLayout());
cards.add(scrollPane, "view");
add(menuPanel, BorderLayout.LINE_START);
add(cards, BorderLayout.CENTER);
}
public void tableChanged(TableModelEvent e) {
int row = e.getFirstRow();
int col = e.getColumn();
model = (MyTableModel) e.getSource();
String stulpPav = model.getColumnName(col);
Object data = model.getValueAt(row, col);
Object studId = model.getValueAt(row, 0);
System.out.println("tableChanded works");
try {
new ImportData(stulpPav, data, studId);
} catch (ClassNotFoundException e1) {
e1.printStackTrace();
} catch (SQLException e1) {
e1.printStackTrace();
}
}
public void actionPerformed(ActionEvent event) {
JComboBox cb = (JComboBox) event.getSource();
String pav = (String) cb.getSelectedItem();
if (pav != "Chose groop") {
try {
model = new MyTableModel(pav);
table.setModel(model);
} catch (SQLException e) {
e.printStackTrace();
}
}
}
private static void GUI() throws SQLException {
JFrame frame = new JFrame("E-gradebook");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setContentPane(new TableCombobox());
frame.pack();
frame.setSize(800, 400);
frame.setVisible(true);
}
public static void main(String[] args) throws SQLException {
try {
Class.forName("com.mysql.jdbc.Driver");
con = DriverManager.getConnection("jdbc:mysql://localhost/pki18",
"root", "");
GUI();
} catch (SQLException e) {
e.printStackTrace();
} catch (ClassNotFoundException e1) {
e1.printStackTrace();
} finally {
if (stmt != null)
stmt.close();
}
}
static Connection getConnection() {
return con;
}
}
public class ImportData {
static Connection con = TableCombobox.getConnection();
public ImportData(String a, Object b, Object c)
throws ClassNotFoundException, SQLException {
Statement stmt = null;
try {
String stulpPav = a;
String duom = b.toString();
String studId = c.toString();
System.out.println(duom);
con.setAutoCommit(false);
stmt = con.createStatement();
stmt.addBatch("update pki18 set " + stulpPav + " = " + duom
+ " where studento_id = " + studId + ";");
stmt.executeBatch();
con.commit();
} catch (BatchUpdateException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
} finally {
if (stmt != null)
stmt.close();
con.setAutoCommit(true);
System.out.println("Data was imported to database");
}
}
}
public class MyTableModel extends AbstractTableModel{
static int rowCount;
static Object data [][];
static String columnNames [];
public MyTableModel(String grupName) throws SQLException{
String query ="select Studento_id, vardas_pavarde, 1_semestras,"+
" 2_semestras, egzaminas, bendras_balas "+
"from pki18." + grupName;
ResultSet rs ;
Connection con = TableCombobox.getConnection();
Statement stmt = null;
stmt = con.createStatement();
rs = stmt.executeQuery(query);
rs.last();
rowCount = rs.getRow();
data = new Object[rowCount][6];
rs = stmt.executeQuery(query);
for (int iEil = 0; iEil < rowCount; iEil++){
rs.next();
data[iEil][0] = rs.getLong("Studento_id");
data[iEil][1] = rs.getString("Vardas_Pavarde");
data[iEil][2] = rs.getByte("1_semestras");
data[iEil][3] = rs.getByte("2_semestras");
data[iEil][4] = rs.getByte("Egzaminas");
data[iEil][5] = rs.getByte("bendras_balas");
}
String[] columnName = {"Asmens_kodas","Vardas_Pavarde","1_Semestras"
,"2_Semestras","Egzaminas","Bendras_Balas"};
columnNames = columnName;
}
public int getColumnCount(){
return columnNames.length;
}
public int getRowCount(){
return data.length;
}
public String getColumnName(int col){
return columnNames[col];
}
public Object getValueAt(int row, int col){
return data[row][col];
}
public Class getColumnClass(int col){
return getValueAt(0, col).getClass();
}
public boolean isCellEditable(int row, int col){
return true;
}
public void setValueAt(Object value, int row, int col){
data[row][col] = value;
fireTableCellUpdated(row, col);
}
}
在構造函數中,僅將表模型偵聽器添加到當前模型中:
table.getModel().addTableModelListener(this);
但是,在操作事件中,您將替換表模型:
model = new MyTableModel(pav); table.setModel(model);
結果,新的表模型將沒有偵聽器,並且您將不再收到通知。 讓actionPerformed
方法也添加偵聽器,並且應該解決您的問題。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.