Question

我正在努力将项目从gambas代码语言翻译成Java。

实际上，JTable的第一列（显示所有查询结果）需要根据单元格中读取的文本使用不同颜色（黄绿青绿色）进行背景绘制，问题是当我尝试获取文本（能够为4种类型的文本切换颜色）或使用任何其他功能，如=＆gt; rs.getString或rs.getNString或rs.getBlob，它将永远不会抛出错误 - ＆gt; java.sql.SQLException: After end of result set。

我一直在寻找这个错误2天，除了我不能写两次循环之外我找不到任何有用的东西 - ＆gt;而（rs.next）。

这是类Database（db）：

public class BaseDeDatos{

Connection conn; 

java.sql.Statement statement = null; 
java.sql.PreparedStatement pst = null; 
java.sql.ResultSet rs = null; 
ResultSetMetaData rsmd = null; 
int columnsNumber = 0; 
int rowsNumber = 0; 

public BaseDeDatos() throws SQLException {
    this.conn = DriverManager.getConnection("my driver"); 
}

public Connection getConn() {
    return conn;
}
}

这是进入MainView类：

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {

        String sql ="";

                    bd.getConn();

                    bd.statement = bd.conn.prepareStatement(sql);

                    bd.rs = bd.statement.executeQuery(sql);


                    // Removing Previous Data
                    while (jTable.getRowCount() > 0) {
                        ((DefaultTableModel) jTable.getModel()).removeRow(0);
                    }

                    bd.rsmd = bd.rs.getMetaData();

                    bd.columnsNumber = bd.rs.getMetaData().getColumnCount();


                    jTable.setModel(resultSetToTableModel(bd.rs)); 
        // this line needs this -> import static net.proteanit.sql.DbUtils.resultSetToTableModel;




                    System.out.println(bd.rs); // CHECKING if the ResultSet Has it's Info Inside

                    String rsString = null;
        bd.rs.getString("1st COLUMN"); // THIS LINE THROWS THE ERROR java.sql.SQLException: After end of result set.

        while (bd.rs.next()) {  // Doesen't matter if i delete the last line the program never goes inside this while (I'dont know why).
                        System.out.println("HELLOW");
                        String em =bd.rs.getString("Estado");
                        rsString = em.replace("Validado", ",");
                        System.out.println(rsString);
                        for(int j = 1; j < bd.columnsNumber; j++){
                            System.out.print(bd.rs.getString(j)+" ");
                            em = bd.rs.getString("Estado");
                            rsString = em.replace("Validado", ",");
                        }

                        System.out.println("\n");
                    }

                    setCustomDbColumns(); 
        // In this method i set up the width of the columns on my jTable nothing more special.

                } catch (SQLException ex) {
                    Logger.getLogger(MainView.class.getName()).log(Level.SEVERE, null, ex);
                    JOptionPane.showMessageDialog(null, ex);
                }finally{
                    try{
                       if (bd.rs != null)
                         bd.rs.close();
                       if (bd.statement != null) 
                         bd.statement.close();
                       /*if (bd.conn != null) 
                         bd.conn.close();*/
                    }catch(SQLException e){}
                 }

错误图 The error pict

Answer 1

你可以实现类似的东西

public void changeTable(JTable table,int column_index) { 
table.getColumnModel().getColumn(column_index).setCellRenderer(new DefaultTableCellRenderer() {

            @Override
            public Component getTableCellRendererComponent(JTable table, Object value,
                    boolean isSelected, boolean hasFocus, int row, int column) {
                final Component c = super.getTableCellRendererComponent(table, value,
                        isSelected, hasFocus, row, column);

                if (!isSelected) {
                    int age = Integer.parseInt(table.getValueAt(row, 1).toString());
     // you can set your own implementation here. As an example I 
     // have checked if the age is over 20 or not. According to the 
     // age return from the table column you get different background colors. 
                    int req_age = 20;
     // in your case req_age can be rs.getString("column_name"); or something
     // you need to check with..
                    if (age < req_age) {
                        c.setBackground(new Color(255, 101, 18));
                    } else {
                        c.setBackground(new Color(0, 204, 0));
                    }

                }
                return c;
            }
        });
    }

例如：

Answer 2

，它将永远无法抛出错误 - ＆gt; java.sql.SQLException：结果集结束后。

jTable.setModel(resultSetToTableModel(bd.rs)); 
bd.rs.getString("1st COLUMN"); // THIS LINE THROWS THE ERROR

是的，resutlSetToModel（...）方法从ResultSet中读取数据，因此您无法再访问ResultSet中的数据。

如果要访问数据，可以从TableModel获取数据。

TableModel model = table.getModel();
Object data = model.getValueAt(0, 0);

根据数据库Query返回的String，为JTable列中的所有单元格设置不同的背景颜色

2 个答案: