我是jtable的新手，我正在使用h2数据库进行处理。我的表中有数百万条记录，因此我使用分页从DB获取每页所需的数据。到目前为止，我已经完成了创建分页按钮，并根据页码从查询中获取数据。
例如，限制设置为100000，如果我在page 1，则查询中的偏移量为0，如果我在page 2，则偏移将为200001等等......
我正在做什么，我正在拨打eventActionListener或分页按钮。这个数字写在按钮上。将其与recorsPerPage和add 1相乘。这给了我正确的偏移量，然后我将新的偏移量传递给查询并获得新的结果。
我需要的是获得新行后的内容。应删除或隐藏上一行，并在jtable上嵌入新行。我跳了一下我解释了这个问题。
所以，这是我的代码：
public class Try {
static Connection conn;
static JPanel panel;
static JTable table;
static JButton buttons;
static int buttonID;
static int totalRows;
static int recordPerPage = 100000;
static int totalPages = 0;
static int offSet = 0;
private static JPanel contentPane;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
createAndShowGUI();
} catch (SQLException e) {
e.printStackTrace();
}
}
});
}
protected static void createAndShowGUI() throws SQLException {
JFrame frame = new JFrame();
frame.setVisible(true);
frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE);
frame.setBounds(30, 50, 1300, 600);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
contentPane.setLayout(new BorderLayout(0, 0));
frame.setContentPane(contentPane);
UIManager.put("TabbedPane.selected", Color.lightGray);
JTabbedPane tabbedPane = new JTabbedPane();
tabbedPane.setBorder(new EmptyBorder(10, 10, 10, 10));
frame.add(tabbedPane);
panel = new JPanel();
tabbedPane.addTab("TABLE", null, panel, null);
tabbedPane.setFont(new Font("Dialog", Font.BOLD | Font.ITALIC, 16));
panel.setBackground(Color.white);
JPanel panel_1 = new JPanel();
tabbedPane.addTab("GRAPH", null, panel_1, null);
panel_1.setBackground(Color.white);
JTable table = new JTable();
panel.add(table);
table.setFillsViewportHeight(true);
createDBConnection();
}
private static void createDBConnection() throws SQLException {
try {
Class.forName("org.h2.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
try {
conn = DriverManager.getConnection("jdbc:h2:file:G:/hs_data/h2_db/test", "sa", "sa");
} catch (SQLException e) {
System.out.println("Unable to make connection with DB");
e.printStackTrace();
}
createPaginationButtons(conn);
}
private static void createPaginationButtons(Connection conn) throws SQLException {
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("SELECT count(*) FROM cdr");
while (rs.next()) {
totalRows = rs.getInt(1);
}
int v = totalRows % recordPerPage == 0 ? 0 : 1;
totalPages = totalRows / recordPerPage + v;
createButton(totalPages);
}
private static void createButton(int totalPages) throws SQLException {
for (int i = 0; i < totalPages;) {
buttons = new JButton("" + (i + 1));
buttons.addActionListener(listener);
panel.add(buttons);
i++;
}
createTable(offSet);
}
static ActionListener listener = new ActionListener() {
public void actionPerformed(ActionEvent e) {
if (e.getSource() instanceof JButton) {
String text = ((JButton) e.getSource()).getText();
buttonID = Integer.parseInt(text);
offSet = (buttonID * recordPerPage) + 1;
try {
createTable(offSet);
} catch (SQLException e1) {
e1.printStackTrace();
}
}
}
};
private static void createTable(int offSet) throws SQLException {
table = new JTable();
Statement stmt1 = conn.createStatement();
JOptionPane.showMessageDialog(null, recordPerPage);
JOptionPane.showMessageDialog(null, offSet);
ResultSet rs1 = stmt1.executeQuery(
"SELECT ANUMBER,BNUMBER,DATETIME FROM CDR LIMIT '" + recordPerPage + "' OFFSET '" + offSet + "' ");
JOptionPane.showMessageDialog(null, offSet);
table.setModel(DbUtils.resultSetToTableModel(rs1));
panel.add(new JScrollPane(table));
}
}
offset方法中createTable()的值根据我的需要而改变，但它不会改变表格行？如何嵌入新行并隐藏/删除之前的？
答案 0 :(得分：1)
基本想法是你只需要更新TableModel
目前，您使用DbUtils每次调用时都会创建一个新的TableModel，而您可以这样做，但效率不高，会影响JTable的其他属性（如列宽）
更好的解决方案是使用DefaultTableModel并自行更新，例如......
private DefaultTableModel model;
private void loadTable(int offset) throws SQLException {
try (PreparedStatement stmt = conn.prepareStatement("SELECT ANUMBER,BNUMBER,DATETIME FROM CDR LIMIT ? OFFSET ?")) {
stmt.setInt(1, recordPerPage);
stmt.setInt(1, offset);
try (ResultSet rs = stmt.executeQuery()) {
ResultSetMetaData rsmd = rs.getMetaData();
int columnCount = rsmd.getColumnCount();
if (model == null) {
String[] columnNames = new String[columnCount];
for (int col = 0; col < columnCount; col++) {
columnNames[col] = rsmd.getColumnName(col + 1);
}
model = new DefaultTableModel(columnNames, 0);
table.setModel(model);
}
model.setRowCount(0);
while (rs.next()) {
Object[] row = new Object[columnCount];
for (int col = 0; col < columnCount; col++) {
row[col] = rs.getObject(col + 1);
}
model.addRow(row);
}
}
}
}
这假设您之前已创建JTable并将其添加到GUI
答案 1 :(得分：0)
所以，这是我在原始代码中更改的内容，并且可以正常工作
private static void createTable(int offSet) throws SQLException {
model.addColumn("ANUMBER");
model.addColumn("BNUMBER");
model.addColumn("DATETIME");
panel.add(new JScrollPane(table));
populateTable(offSet);
}
private static void populateTable(int offSet2) throws SQLException {
while (model.getRowCount() > 0) {
model.removeRow(0);
}
Statement stmt1 = conn.createStatement();
ResultSet rs1 = stmt1.executeQuery(
"SELECT ANUMBER,BNUMBER,DATETIME FROM CDR LIMIT '" + recordPerPage + "' OFFSET '" + offSet + "' ");
while(rs1.next()) {
x = rs1.getString("ANUMBER");
y = rs1.getString("BNUMBER");
z = rs1.getString("DATETIME");
model.addRow(new Object[]{x, y, z});
}
}