如何动态地将JCheckBox添加到从MySQL数据库检索到JTable的每一行

Question

I have data from the database on my JTable . I want to add checkboxes to each row dynamically from the database. I will later use these checkboxes to delete rows checked from the database. I know how to delete from the database, but how to add checkboxes from the database? Any one done this before please help. I am a Java enthusiast trying to learn it. A sample code could help me understand how to do this.

Code below is for updating my JTable :

public void UpdateTable() {

    try {

        Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/"
                + "employee_certificate", "root", "");

        String sql = "SELECT certificate.Number, staff.Emp_Id, staff.Emp_Name, "
                + "staff.Department,  certificate.Cert_Code, certificate.Cert_Name,\n"
                + "certificate.Vendor, certificate.Date_Taken, "
                + "certificate.Expiry_Date FROM staff LEFT JOIN certificate"
                + " ON staff.Emp_Id=certificate.Emp_Id ORDER BY staff.Emp_Name\n";

        PreparedStatement pstmt = con.prepareStatement(sql);
        ResultSet rs = pstmt.executeQuery();
        jTable1.setModel(DbUtils.resultSetToTableModel(rs));
    } catch (Exception e) {
        JOptionPane.showMessageDialog(null, e);
    }
}

Answer 1

Starting from this complete example , I made the changes below to get the following result. In particular,

• Row is given an attribute Boolean checked , replacing String name .

• The default renderer uses a check box when getColumnClass() returns Boolean.class for Row.checked .

• In the corresponding JDBC and SQL, the checked attribute is of type boolean .

$ diff Original.java WorkerTest.java 
48c48
<         String name;
---
>         Boolean checked;
91c91
<                     return row.name;
---
>                     return row.checked;
105a106,116
>         @Override
>         public Class<?> getColumnClass(int colIndex) {
>             switch (colIndex) {
>                 case 0:
>                     return Integer.class;
>                 case 1:
>                     return Boolean.class;
>             }
>             return null;
>         }
> 
114c125
<                         r.name = rs.getString(2);
---
>                         r.checked = rs.getBoolean(2);
138c149
<             st.execute("create table city(id integer, name varchar2)");
---
>             st.execute("create table city(id integer, checked boolean)");
143,144c154
<                 ps.setString(2, (char) ('A' + r.nextInt(26))
<                     + String.valueOf(r.nextInt(1_000_000)));
---
>                 ps.setBoolean(2, Boolean.valueOf(r.nextBoolean()));

Answer 2

The problem is DBUtils returns a complete TableModel .

The easiest way is to NOT use DBUtils and to load the data from the ResultSet into the TableModel yourself.

The code is not difficult and you can use the Table From Database Example found in Table From Database as the starting point.

The code just loads the data from the ResultSet into Vectors, so you can then manually add another column to contain Boolean data.

The (two) changes to the code would be something like:

//  Get column names

for (int i = 1; i <= columns; i++)
{
    columnNames.addElement( md.getColumnName(i) );
}

columnName.addElement( "Check Mark" ); // added

//  Get row data

while (rs.next())
{
    Vector<Object> row = new Vector<Object>(columns);

    for (int i = 1; i <= columns; i++)
    {
        row.addElement( rs.getObject(i) );
    }

    row.addElement( Boolean.FALSE ); // added
    data.addElement( row );
}