获取：使用MySQL列中的JDBC输出1970年1月1日

Question

I am trying to show the data of a Table from MySQL server, into a JFrame I am creating. Although everything else works great i cant seem to get correct the TIME data from the corresponding columns.

My code, as well as an example of the output, follows!

package pkginterface;

import java.awt.*; 
import java.sql.*;
import java.util.*;
import javax.swing.*; 
import javax.swing.table.*;
import java.time.*;


public class Staff_Info extends JFrame
{
public Staff_Info()
{
    ArrayList columnNames = new ArrayList();
    ArrayList data = new ArrayList();

    String url = "jdbc:mysql://localhost:3306/cinema";
    String userid = "root";
    String password = "password";
    String sql = "SELECT * FROM TimeTable";


    try (Connection connection = DriverManager.getConnection( url, userid, password );
        Statement stmt = connection.createStatement();
        ResultSet rs = stmt.executeQuery( sql ))
    {
        ResultSetMetaData md = rs.getMetaData();
        int columns = md.getColumnCount();


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


        while (rs.next())
        {
            ArrayList row = new ArrayList(columns);

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

            data.add( row );
        }
    }
    catch (SQLException e)
    {
        System.out.println( e.getMessage() );
    }


    Vector columnNamesVector = new Vector();
    Vector dataVector = new Vector();

    for (int i = 0; i < data.size(); i++)
    {
        ArrayList subArray = (ArrayList)data.get(i);
        Vector subVector = new Vector();
        for (int j = 0; j < subArray.size(); j++)
        {
            subVector.add(subArray.get(j));
        }
        dataVector.add(subVector);
    }

    for (int i = 0; i < columnNames.size(); i++ )
        columnNamesVector.add(columnNames.get(i));

    //  Create table with database data    
    JTable table = new JTable(dataVector, columnNamesVector)
    {
        public Class getColumnClass(int column)
        {
            for (int row = 0; row < getRowCount(); row++)
            {
                Object o = getValueAt(row, column);

                if (o != null)
                {
                    return o.getClass();
                }
            }

            return Object.class;
        }
    };

    JScrollPane scrollPane = new JScrollPane( table );
    getContentPane().add( scrollPane );

    JPanel buttonPanel = new JPanel();
    getContentPane().add( buttonPanel, BorderLayout.SOUTH );
    pack();

}

public static void main(String[] args)
{
    Staff_Info frame = new Staff_Info();
    frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
    frame.pack();
    frame.setVisible(true);
}
}

And here you can see the above output!

I am working on Ubuntu 14.04 with MySQL Workbench and NetBeans.

Both of the timetable_starttime and timetalbe_endtime fields, have the TIME datatype in their table creation as long as a valid insert field.

Here you can see the MySQL Select * statement for that table.

I figured out that there has something to do with Epoch time but I wasn't able to find an actual solution to the problem!

Any help would be greatly appreciated!

Thanks for your time!

Answer 1

As to this documentation , the call to rs.getObject(i) will return an instance of java.sql.Time for your TIME columns.

java.sql.Time is a subclass of java.util.Date

Unfortunately, JTable does not have a default Renderer in place for java.sql.Time . But is does have one for java.util.Date - which uses a short date format for display - defaulting to showing only the date part, which is all zero for a Time - so it's always Januar 1st 1970

So how to fix this?

Add a custom renderer to your JTable with a specific Renderer for Time:

TableCellRenderer tableCellRenderer = new DefaultTableCellRenderer() {

    SimpleDateFormat f = new SimpleDateFormat("HH:mm:ss");

    public Component getTableCellRendererComponent(JTable table,
            Object value, boolean isSelected, boolean hasFocus,
            int row, int column) {
        if( value instanceof Time) {
            value = f.format(value);
        }
        return super.getTableCellRendererComponent(table, value, isSelected,
                hasFocus, row, column);
    }
};
table.setDefaultRenderer(Time.class, tableCellRenderer);

Good Luck.