java - 如何在单击按钮而不清除现有行的情况下将新行从数据库添加到 jTable

Question

如何在不清除 jTable 中现有行的情况下单击按钮时从数据库向 jTable 添加新行？

我尝试了很多方法。但没有成功。帮助

String SQL = "SELECT name,price FROM items WHERE ID = ' "+jTextField1.getText()+" ' ";
pst = Conn.prepareStatement(sql);
rs = pst.executeQuery();
jTable1.setModel(DbUnits.resultSetToTableModel(rs));

编辑:-在所有答案的帮助下，我将代码更改为以下代码，但是好的 。但是这里我在 DefaultTableModel

中遇到错误

String sql = "SELECT name,price FROM items WHERE ID = '"+jtxt1.getText()+"'";
        pst = conn.prepareStatement(sql);
        rs=pst.executeQuery();
DefaultTableModel model = new DefaultTabelModel(new String[]{"Name","Price"},0);
        Vector row = new Vector();
        while(rs.next())
        {
        String d = rs.getString("name");
        String e = rs.getString("price");
        row.add(new Object[]{d,e});

        model.addRow(row);}

新代码

String sql = "SELECT name,price FROM items WHERE ID = '"+jtxt1.getText()+"'";
        pst = conn.prepareStatement(sql);
        rs=pst.executeQuery();
        DefaultTableModel model=(DefaultTableModel)jTable1.getModel();
Vector row = new Vector();
row.add(rs);
model.addRow(row);

最新代码

ResultSetMetaData metaData;
public void metaData() throws SQLException {
        this.metaData = rs.getMetaData();
        }
String sql = "SELECT name,price FROM items WHERE ID = '"+jtxt1.getText()+"'";
            pst = conn.prepareStatement(sql);
            rs=pst.executeQuery();

            int columnCount = metaData.getColumnCount();
            Vector<String> columnNames = new Vector<String>();

            for (int column = 1; column <= columnCount; column++) {
                columnNames.add(metaData.getColumnName(column));
                System.out.println("ColumnNames "+columnNames );
            }

            DefaultTableModel datamodel = new DefaultTableModel(columnNames, 0);
            jTable1.setModel(datamodel);

            while (rs.next()) {
                Vector<String> vector = new Vector<String>();
                for (int columnIndex = 1; columnIndex <= columnCount; columnIndex++) {
                vector.add(rs.getString(columnIndex)); 
                }
                datamodel.addRow(vector);
            }

**但是在这里我得到一个 NullpointException 错误!我如何选择 jTable1 作为上面代码中的表？

Answer 1

处理 ResultSet 中的每一行数据并创建一个 Vector 和 use this method将数据插入表模型。您正在创建新的表模型并将其设置在表上，带有数据的旧模型将丢失。

在评论中提出以下要求后:

这是一种方法。

Vector<Vector<String>> data=new Vector<>();
//Fill this Vector above with the initial data

Vector<String> columns=new Vector<String>();
//Fill this with column names

DefaultTableModel tableModel=new DefaultTableModel(data, columns);
JTable table=new JTable(tableModel);
//Display the table as you like

... //Query the database and get the ResultSet (let's call it rs)

while(rs.next){

  Vector<String> newRow=new Vector<>();

  //Get the data from the resultset and fill this new row

  tableModel.addRow(newRow);

}//while closing