根据来自 msyql 的结果集值更改 Jtable 单元格的颜色

Question

I use Netbeans to develop a java application, I have a result set from MYSQL database and i want to put this data in a JTable. I have a problem when I want to change background color of a JTable cell based on its value (ex: if the value of a cell in Jtable isn't equal to 1, its color must be red). Here is my code:

    /*
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 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * 
 */
import java.awt.Color;
import java.awt.Component;
import java.awt.Font;
import java.sql.*;
import java.util.Vector;
import javax.swing.JTable;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumn;

public class Cell2 {

    // JDBC driver name and database URL
    static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
    static final String DB_URL = "jdbc:mysql://localhost/db";

    //  Database credentials
    static final String USER = "root";
    static final String PASS = "(abdc)";

    public void queryABTS(JTable table) {
        Connection conn = null;
        Statement stmt = null;
        try {
            //STEP 2: Register JDBC driver
            Class.forName("com.mysql.jdbc.Driver");

            //STEP 3: Open a connection
            System.out.println("Connecting to database...");
            conn = DriverManager.getConnection(DB_URL, USER, PASS);

            //STEP 4: Execute a query
            System.out.println("Creating statement...");
            stmt = conn.createStatement();
            String sql;
            sql = "SELECT * from dbn;";
            ResultSet rs = stmt.executeQuery(sql);
            ResultSetMetaData rsmt = rs.getMetaData();
            int c = rsmt.getColumnCount();
            Vector column = new Vector(c);
            for (int i = 1; i <= c; i++) {
                column.add(rsmt.getColumnName(i));
            }
            Vector data = new Vector();
            Vector row = new Vector();
            while (rs.next()) {
                row = new Vector(c);
                for (int i = 1; i <= c; i++) {
                    row.add(rs.getString(i));
                }
                data.add(row);
            }

            table.setModel(new javax.swing.table.DefaultTableModel(data, column));
            table.getTableHeader().setFont(new Font("SansSerif", Font.BOLD, 13));
           // table.getValueAt(1, 1);

            TableColumn column1 = null;

            for (int i = 0; i < 5; i++) {
                column1 = table.getColumnModel().getColumn(i);
                if (i == 3) {
                    column1.setPreferredWidth(150); //third column is bigger

                } else {
                    column1.setPreferredWidth(50);

                }
            }

            setCellRenderer(table);
            //color cell =======================================================================

             // end color cell ==================================================================


//========================================================

//=======================================================
            //STEP 6: Clean-up environment
            rs.close();
            stmt.close();
            conn.close();
        } catch (SQLException se) {
            //Handle errors for JDBC
            se.printStackTrace();
        } catch (Exception e) {
            //Handle errors for Class.forName
            e.printStackTrace();
        } finally {
            //finally block used to close resources
            try {
                if (stmt != null) {
                    stmt.close();
                }
            } catch (SQLException se2) {
            }// nothing we can do
            try {
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException se) {
                se.printStackTrace();
            }//end finally try
        }//end try
        System.out.println("Goodbye!");
    }//end main  


public static TableCellRenderer createCellRenderer() {
    return new DefaultTableCellRenderer() {
        @Override
        public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
            Component c =  super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);

            if (column == 4 && "1".equals((String) value)) {
    c.setBackground(Color.RED);
    }

            return c;
        }
    };
}

public static void setCellRenderer(JTable table) {
    TableCellRenderer cellRenderer = createCellRenderer();
    table.setDefaultRenderer(Object.class, cellRenderer);
}





}

Answer 1

Try this

public static TableCellRenderer createCellRenderer() {
    return new DefaultTableCellRenderer() {
        @Override
        public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
            Component c =  super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);

            c.setBackground(Color.GREEN);

            return c;
        }
    };
}

public static void setCellRenderer(JTable table) {
    TableCellRenderer cellRenderer = createCellRenderer();
    table.setDefaultRenderer(Object.class, cellRenderer);
}

By calling table.setModel(new javax.swing.table.DefaultTableModel(data, column)); you are putting your data into the table model. JTable uses by default DefaultTableCellRenderer instance to render cells, which can be replaced by your own cell renderer by calling table.setDefaultRenderer(Integer.class, cellRenderer) - this will set custom cellrenderer to all Integer columns ( DefaultTableModel uses Object columns). When table is being displayed, each cell of the table is customized by getTableCellRendererComponent(...) method of the table's cellrenderer. In this method, you have current component (cell) with it's value and position (see parameters), that you can use to customize your cell before getting rendered.

So if you want to set background color to RED for each cell in second column with value 1, you would write:

if (column == 1 && ((Integer) value) == 1) {
    c.setBackground(Color.RED);
}

Passing table's data to cell renderer

public static TableCellRenderer createCellRenderer(final Vector data) {
    return new DefaultTableCellRenderer() {
        @Override
        public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
        Component c =  super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);

            // use data to customize current component

            return c;
        }
    };
}

public static void setCellRenderer(JTable table, Vector data) {
    // Vector data = ((DefaultTableModel) table.getModel()).getDataVector();
    TableCellRenderer cellRenderer = createCellRenderer(data);
    table.setDefaultRenderer(Object.class, cellRenderer);
}

Answer 2

public class Product extends javax.swing.JPanel {
     
    public Product() {
        initComponents();
         
       getNewRenderedTable(p_table);
       
    }
      
    private static JTable getNewRenderedTable(final JTable table){
        table.setDefaultRenderer(Object.class, new DefaultTableCellRenderer(){
            @Override
            public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column){
                super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
                
                int status = Integer.parseInt((String) table.getModel().getValueAt(row, 7));
                
                if(status<=5){
                   setBackground(Color.red);
                   setForeground(Color.WHITE);
                }
                else{
                   setBackground(Color.WHITE);
                   setForeground(Color.black);
                }
                return this;
            }
        });
        return table;
    }

}