添加數據庫中不存在的額外列

Question

以下是我的數據庫中創建表的代碼。我想在末尾添加一個複選框列，它不在數據庫中。它只是前端的一部分。你能幫忙嗎？

我的getRow（）方法保持返回-1，儘管選擇了一行，任何建議？

package Default; 
import javax.swing.*; 
import javax.swing.event.ListSelectionEvent; 
import javax.swing.event.ListSelectionListener; 
import javax.swing.table.*; 
import java.sql.*; 

/** 
* This class create JTable from Database table. 
* User program needs to specify database connection and corresponding a table name. 
* 
*/ 

public class DBTable{ 
//private String table; 

DefaultTableModel dm=new DefaultTableModel(); 
JTable t1=new JTable(); 
Object row[]; 
String c[]; 
int cols; 
PreparedStatement pst; 
ResultSet rs ; 

public DBTable(Connection conn){ 
    conn=Login.con; 
} 

/** 
* This method return JTable object created from Database table having selected data and structur  * as in original table into database. 
* @param table Name of the database table to be coverted to JTable 
* @param query Select query to specify selected columns and data to extracted from database table 
* @return JTable object that consist of selected data and structure of Database table 
* @throws java.lang.Exception Original object is deferent, e.i either SQLException or NullPointerException 
*/ 

public JTable getTable(String table,String query)throws Exception{ 

    JTable t1=new JTable(); 
    DefaultTableModel dm=new DefaultTableModel(); 
    Statement st= Login.con.createStatement(); 
    ResultSet rs=st.executeQuery(query); 
    ResultSetMetaData rsmd=rs.getMetaData(); 
    //Coding to get columns- 
    int cols=rsmd.getColumnCount(); 
    String c[]=new String[cols]; 
    for(int i=0;i<cols;i++){ 
     c[i]=rsmd.getColumnName(i+1); 
     dm.addColumn(c[i]); 
    } 



    //get data from rows 
    Object row[]=new Object[cols]; 
    while(rs.next()){ 
     for(int i=0;i<cols;i++){ 
       row[i]=rs.getString(i+1); 
      } 
     dm.addRow(row); 
    } 
    t1.setModel(dm); 


    return t1; 
} 


     public int getRow(){ 

int row = t1.getSelectedRow(); 
JOptionPane.showMessageDialog(null, row); 

    return row; 
} 

public void deleteRow(String sql){ 

try { 
    String value = (String) t1.getValueAt(getRow(), 0); 
    JOptionPane.showMessageDialog(null, value); 
    pst = Login.con.prepareStatement(sql); 
    pst.setString(1, value); 
    ((DefaultTableModel)t1.getModel()).removeRow(getRow()); 
    pst.execute(); 
    JOptionPane.showMessageDialog(null, "Deleted"); 


    } catch (Exception e) { 
     e.printStackTrace(); 
     JOptionPane.showMessageDialog(null, e); 
    } 
} 
} 

Answer 1

您正在使用的DefaultTableModel，所以你創建模型後，您可以手動添加列：

model.addColumn("CheckBox Column");