Javaサンプル(イメージファイル入出力)

//Sample1D
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Sample1d extends JFrame implements ActionListener {
  private static final String window_title = "イメージファイル入出力";
  private static final int window_width = 640;
  private static final String bt01_title = "開く";
  private static final int window_height = 400;
  private static final long serialVersionUID = 1L;
  private static final String bt01_code = "Open";
  private static final String bt02_title = "保存";
  private static final String bt02_code = "Save";
  JFileChooser fc = new JFileChooser();
  JButton bt01;
  JButton bt02;
  BufferedImage img = null;
  // 主処理
  public static void main(final String ar[]) {
    final JFrame f = new Sample1d();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.setSize(Sample1d.window_width, Sample1d.window_height);
    f.setVisible(true);
  }
  // 部品セット
  Sample1d() {
    super(Sample1d.window_title);
    this.bt01 = new JButton(Sample1d.bt01_title);
    this.bt01.setActionCommand(Sample1d.bt01_code);
    this.bt01.addActionListener(this);
    this.bt02 = new JButton(Sample1d.bt02_title);
    this.bt02.setActionCommand(Sample1d.bt02_code);
    this.bt02.addActionListener(this);
    final Container c = this.getContentPane();
    final JPanel p1 = new JPanel();
    p1.add(this.bt01);
    p1.add(this.bt02);
    c.add(p1, BorderLayout.NORTH);
  }
  // イベント
  public void actionPerformed(final ActionEvent ae) {
    if (ae.getActionCommand() == Sample1d.bt01_code) {
      final int fd = this.fc.showOpenDialog(this);
      try {
        if (fd == JFileChooser.APPROVE_OPTION) {
          try {
            this.img = ImageIO.read(this.fc.getSelectedFile());
            this.repaint();
          } catch (final Exception e) {
          }
        }
      } catch (final Exception e) {
      }
    } else if (ae.getActionCommand() == Sample1d.bt02_code) {
      final int fd = this.fc.showSaveDialog(this);
      try {
        if (fd == JFileChooser.APPROVE_OPTION) {
          try {
            final boolean rc = ImageIO.write(this.img, "jpeg",
                this.fc.getSelectedFile());
            this.repaint();
          } catch (final Exception e) {
          }
        }
      } catch (final Exception e) {
      }
    }
  }
  // 描画
  @Override
  public void update(final Graphics g) {
    this.paint(g);
  }
  @Override
  public void paint(final Graphics g) {
    final Graphics2D g2 = (Graphics2D) g;
    if (this.img == null) {
      g.clearRect(0, 0, Sample1d.window_width - 1,
          Sample1d.window_height - 1);
    } else {
      g2.drawImage(this.img, 0, 0, this);
      final Graphics2D g3 = this.img.createGraphics();
      g3.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
          RenderingHints.VALUE_ANTIALIAS_ON);
      final Font font = new Font("Arial", Font.PLAIN, 24);
      g3.setFont(font);
      g3.setColor(Color.red);
      g3.drawString("hear", 100, 100);
    }
    if (this.img != null) {
      g2.drawImage(this.img, 0, 0, this);
    }
    this.bt01.repaint();
    this.bt02.repaint();
  }
}