java之数字彩虹雨

思考1：深克隆与浅克隆

思考2：定义方法访问私有变量

思考3：多线程

定义俩个类

Rain，RainPanel

（放个帖，以后再看）

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Toolkit;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import javax.swing.JDialog;
import javax.swing.JOptionPane;
import javax.swing.JPanel;

public final class BinaryRain extends JDialog {
  public static void main(String[] args) {
    BinaryRain r = new BinaryRain();
    r.setVisible(true);
    r.start();
  }

  private BinaryRain() {
    try {
      init();
    } catch (Exception ex) {
      JOptionPane.showMessageDialog(null, "Failed to init.\n" + ex, "BinaryRain", JOptionPane.ERROR_MESSAGE);
      System.exit(1);
    }
  }

  private Dimension size;
  private Color foreground, background;
  public char[] RAIN_CHARACTERS;
  private Font rainFont;

  private void init() {
    size = Toolkit.getDefaultToolkit().getScreenSize();
    foreground = Color.GREEN;
    background = Color.BLACK;
    rainFont = new Font("arial", Font.BOLD, 15);
    RAIN_CHARACTERS = new char[126 - 33 + 1];
    for (int c = 0, i = 33, l = RAIN_CHARACTERS.length; c < l; c++, i++)
      RAIN_CHARACTERS[c] = (char) i;
    setUndecorated(true);
//    setAlwaysOnTop(true);
//    setResizable(false);
//    setTitle("Binary Rain");
//    setLocationRelativeTo(null);
    BufferedImage cursor = new BufferedImage(16, 16, BufferedImage.TYPE_INT_ARGB_PRE);
    setCursor(Toolkit.getDefaultToolkit().createCustomCursor(cursor, new Point(8, 8), "Disable Cursor"));
    setSize(size);
    addKeyListener(new KeyAdapter() {
      @Override
      public void keyPressed(KeyEvent event) {
        if ((event.isAltDown() && event.getKeyCode() == KeyEvent.VK_F4) || (event.getKeyCode() == KeyEvent.VK_ESCAPE)) {
          setVisible(false);
          System.exit(0);
        }
      }
    });
    addWindowListener(new WindowAdapter() {
      @Override
      public void windowClosing(WindowEvent event) {
        if (!isRaining())
            isStart = false;
        System.exit(0);
      }
    });
    add(panel, BorderLayout.CENTER);
  }

  private synchronized void newRain() {
    Rain r = new Rain((int) (Math.random() * 40 + 10), (int) (Math.random() * size.width), (int) (Math.random() * -60 * 15), (int) (Math.random() * 8 + 2), (float) (Math.random() * 10 + 10));
    rains.add(r);
    new Thread(r).start();
  }
  private ArrayList rains = new ArrayList<>();

  public void start() {
    for (int c = 0, s = 108; c < s; c++)
      newRain();
    isStart = true;
    new Thread(new Runnable() {
      @Override
      public void run() {
        while (isStart)
          panel.repaint();
      }
    }).start();
  }

  public boolean isRaining() {
    return isStart;
  }

  public String getRandomChar() {
    return String.valueOf(RAIN_CHARACTERS[(int) (Math.random() * RAIN_CHARACTERS.length)]);
  }

  private RainPanel panel = new RainPanel();
  private boolean isStart = false;

  private final class RainPanel extends JPanel {
    @Override
    public void paint(Graphics g) {
      if (isStart) {
        BufferedImage img = new BufferedImage(size.width, size.height, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = (Graphics2D) img.getGraphics();
        g2.setColor(background);
        g2.fillRect(0, 0, size.width, size.height);
        g2.setColor(foreground);
        Collection collection = (Collection) rains.clone();
        for (Iterator it = collection.iterator(); it.hasNext();) {
          Rain r = it.next();
          if (r.isEnd()) {
            rains.remove(r);
            newRain();
            continue;
          }
            g2.setFont(rainFont.deriveFont(r.fontSize));
            String[] ss = r.getRainChars();
            int x = r.rainX;
            int y = r.rainY - ss.length * 15;
            for (String s : ss) {
              g2.drawString(s, x, y);
              y += 15;
          }
        }
        g.drawImage(img, 0, 0, this);
      }
    }
  }

  private final class Rain implements Runnable {
    private final String[] rainChars;
    private int rainSpeed;
    private int rainX, rainY;
    private float fontSize;

    public Rain(int length, int x, int y, int speed, float size) {
      rainChars = new String[length + 1];
      for (int i = 0; i < length; i++)
        rainChars[i] = getRandomChar();
      rainChars[length] = " ";
      this.rainX = x;
      this.rainY = y;
      this.rainSpeed = speed;
      this.fontSize = size;
    }

    @Override
    public void run() {
      while (isRaining() && rainY < size.height + (rainChars.length + 1) * 15) {
        if (rainSpeed <= 0)
          break;
        try {
          Thread.sleep(rainSpeed);
        } catch (InterruptedException ex) {
        }
        rainY += 2;
      }
      rainSpeed = -1;
    }

    public String[] getRainChars() {
      return rainChars;
    }

    public boolean isEnd() {
      return rainSpeed <= 0;
    }
  }
}