优化JDBC中的数据调用到JTable上
目前我在MySQL服务器上有数据，我通过JDBC将数据调用到JTable。 但是有1369行，似乎它有太多的数据要加载。 通常需要5分钟才能加载。 有没有优化过程？ 这是我的代码（我提前为一个混乱的代码道歉）：
public class DataTable { private String databaseName = "*****"; private String tableName = "******"; public void showDatabase(){ Connection conn = null; DatabaseMetaData meta = null; Statement stmt = null; ResultSet rs = null; int k = 0; try{ Class.forName("com.mysql.jdbc.Driver").newInstance(); String connectionUrl = "jdbc:mysql://localhost:3306/" + databaseName; String connectionUser = "*****"; String connectionPassword = "*****"; conn = DriverManager.getConnection(connectionUrl, connectionUser, connectionPassword); stmt = conn.createStatement(); meta = conn.getMetaData(); dataSets(stmt, meta); }catch(Exception e){ e.printStackTrace(); } finally{ try { if (rs != null) rs.close(); } catch (SQLException e) { e.printStackTrace(); } try { if (stmt != null) stmt.close(); } catch (SQLException e) { e.printStackTrace(); } try { if (conn != null) conn.close(); } catch (SQLException e) { e.printStackTrace(); } } } //return the column size of the table public int getColumnNumber(DatabaseMetaData meta, Statement stmt) throws SQLException { //ResultSet rs = meta.getColumns(null, null, "practiceexample", null); ResultSet rs = stmt.executeQuery("SELECT * FROM " + tableName); ResultSetMetaData rsmd = rs.getMetaData(); int columnsNumber = rsmd.getColumnCount(); return columnsNumber; } //return the rowNumber of the tables public int getRowNumber(Statement stmt) throws SQLException { ResultSet rs = stmt.executeQuery("SELECT COUNT(*) FROM " + tableName); int rowCount = 0; while(rs.next()){ rowCount = rs.getInt(1); } return rowCount; } public void dataSets(Statement stmt, DatabaseMetaData meta) throws SQLException { String[] columnNames = new String[getColumnNumber(meta, stmt)]; String[][] dataSets = new String[getRowNumber(stmt)][columnNames.length]; ResultSet column = meta.getColumns(null, null, tableName, null); int i = 0; while(column.next()) { columnNames[i] = column.getString("COLUMN_NAME"); //columnNames.add(i, column.getString("COLUMN_NAME")); i++; } for(int j = 0; j < dataSets.length; j++) { String[] singleRowData = new String[columnNames.length]; ResultSet data = null; for(int k = 0; k "); next.addActionListener(new ActionListener(){ public void actionPerformed(ActionEvent e) { int height = table.getRowHeight() * (20-1); JScrollBar bar = scrollPane.getVerticalScrollBar(); bar.setValue(bar.getValue() + height); } }); JButton previous = new JButton("<"); previous.addActionListener( new ActionListener(){ public void actionPerformed(ActionEvent ae) { int height = table.getRowHeight()*(20-1); JScrollBar bar = scrollPane.getVerticalScrollBar(); bar.setValue( bar.getValue()-height ); } } ); navigation.add(previous); navigation.add(next); gui.add(scrollPane, BorderLayout.CENTER); gui.add(navigation, BorderLayout.SOUTH); JOptionPane.showMessageDialog(null, gui); } } } 恕我直言，糟糕的permormance的根源是您不必要地查询数据库多次以获取您需要的数据（列，行，行号，列号等）：
要获得列号：
ResultSet rs = stmt.executeQuery("SELECT * FROM " + tableName);
获取行号：
ResultSet rs = stmt.executeQuery("SELECT COUNT(*) FROM " + tableName);
获取行（这是最糟糕的，因为它在循环中）：
data = stmt.executeQuery("SELECT " + columnName + " FROM " + tableName + " LIMIT " + j + ", " + 1);
如何解决它
只查询一次数据库。 单个ResultSet及其关联的ResultSetMetaData应足以实现您的目标。 另外，正如已经建议的那样，使用SwingWorker在单独的线程中进行数据库调用。 例如：
final JTable table = new JTable(); SwingWorker worker = new SwingWorker () { @Override protected Void doInBackground() throws Exception { ResultSet resultSet = stmt.executeQuery("SELECT * FROM " + tableName); ResultSetMetaData metaData = resultSet.getMetaData(); int columnCount = metaData.getColumnCount(); // columns number String[] columnNames = new String[columnCount]; for (int i = 1; i <= columnCount; i++) { columnNames[i] = metaData.getColumnName(i); // fill columns names } resultSet.last(); int rowCount = resultSet.getRow(); // get rows number resultSet.beforeFirst(); Object[][] data = new Object[rowCount][columnCount]; int currentRow = 0; while (resultSet.next()) { for (int currentColumn = 1; currentColumn <= columnCount; currentColumn++) { data[currentRow][currentColumn - 1] = resultSet.getObject(currentColumn); // fill data set } currentRow++; } TableModel model = new DefaultTableModel(data, columnNames); publish(model); return null; } @Override protected void process(List chunks) { TableModel model = chunks.get(0); table.setModel(model); } } worker.execute();