Save color components of an image separately in a MySQL database

GetImageColorComponents.java

package stackoverflow;

import java.awt.Color;
import java.awt.image.BufferedImage;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.Arrays;

import javax.imageio.ImageIO;
import javax.sql.rowset.serial.SerialBlob;

import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;

public class GetImageColorComponents {
  public static void main(String... args) throws Exception {
    BufferedImage img = ImageIO.read(GetImageColorComponents.class
                                     .getResourceAsStream("/image.png"));
    int[] colors = new int[img.getWidth() * img.getHeight()];
    img.getRGB(0, 0, img.getWidth(), img.getHeight(), colors, 0, img.getWidth());
    
    byte[] red = new byte[colors.length];
    byte[] green = new byte[colors.length];
    byte[] blue = new byte[colors.length];
    
    for (int i = 0; i < colors.length; i++) {
      Color color = new Color(colors[i]);
      red[i] = (byte) color.getRed();
      green[i] = (byte) color.getGreen();
      blue[i] = (byte) color.getBlue();
    }
    
    MysqlDataSource db = new MysqlDataSource();
    db.setDatabaseName("test");
    Connection conn = db.getConnection("test", "test");
    
    setupDb(conn);
    PreparedStatement stmt = conn.prepareStatement("INSERT INTO image " +
                          "(name, red, green, blue) VALUES (?, ?, ?, ?)");
    stmt.setString(1, "foo");
    stmt.setBlob(2, new SerialBlob(red));
    stmt.setBlob(3, new SerialBlob(green));
    stmt.setBlob(4, new SerialBlob(blue));
    
    stmt.execute();
    
    stmt = conn.prepareStatement("SELECT * FROM image WHERE name = ? LIMIT 1");
    stmt.setString(1, "foo");
    ResultSet res = stmt.executeQuery();
    
    res.next();
    
    byte[] storedRed = getBytes(res.getBlob("red"));
    byte[] storedGreen = getBytes(res.getBlob("green"));
    byte[] storedBlue = getBytes(res.getBlob("blue"));
    
    assert Arrays.equals(red, storedRed);
    assert Arrays.equals(green, storedGreen);
    assert Arrays.equals(blue, storedBlue);
    
    for (int i = 0; i < colors.length; i++) {
      Color color = new Color(storedRed[i] & 0xFF, storedGreen[i] & 0xFF, storedBlue[i] & 0xFF, 0xFF);
      assert colors[i] == color.getRGB();
    }
    
    conn.close();
  }
  
  private static byte[] getBytes(Blob blob) throws Exception {
    return blob.getBytes(1, (int) blob.length());
  }
  
  public static void setupDb(Connection conn) throws Exception {
    conn.prepareStatement("DROP TABLE IF EXISTS image").execute();
    conn.prepareStatement("CREATE TABLE image (" +
                                 "name text," +
                                 "red blob," +
                                 "green blob," +
                                 "blue blob)").execute();
    
  }
}

Enable assertions when runnnig this program by passing -ea to the JVM