马凯军201771010116《面向对象与程序设计Java》第十六周知识学习总结

package bounceThread;

import java.awt.geom.*;

/**
   A ball that moves and bounces off the edges of a 
   rectangle
 * @version 1.33 2007-05-17
 * @author Cay Horstmann
*/
public class Ball//该类主要定义了小球的大小及其属性
{
   private static final int XSIZE = 15;
   private static final int YSIZE = 15;
   private double x = 0;
   private double y = 0;
   private double dx = 1;
   private double dy = 1;

   /**
      Moves the ball to the next position, reversing direction
      if it hits one of the edges
   */
   public void move(Rectangle2D bounds)
   {
      x += dx;
      y += dy;
      if (x < bounds.getMinX())
      { 
         x = bounds.getMinX();
         dx = -dx;
      }
      if (x + XSIZE >= bounds.getMaxX())
      {
         x = bounds.getMaxX() - XSIZE; 
         dx = -dx; 
      }
      if (y < bounds.getMinY())
      {
         y = bounds.getMinY(); 
         dy = -dy;
      }
      if (y + YSIZE >= bounds.getMaxY())
      {
         y = bounds.getMaxY() - YSIZE;
         dy = -dy; 
      }
   }

   /**
      Gets the shape of the ball at its current position.
   */
   public Ellipse2D getShape()
   {
      return new Ellipse2D.Double(x, y, XSIZE, YSIZE);
   }
}

package bounceThread;

import java.awt.*;
import java.util.*;
import javax.swing.*;

/**
 * The component that draws the balls.
 * @version 1.34 2012-01-26
 * @author Cay Horstmann
 */
public class BallComponent extends JComponent
{
   private static final int DEFAULT_WIDTH = 450;
   private static final int DEFAULT_HEIGHT = 350;

   private java.util.List<Ball> balls = new ArrayList<>();//构造一个初始容量为 10 的空列表。
//此接口的用户可以对列表中每个元素的插入位置进行精确地控制。用户可以根据元素的整数索引（在列表中的位置）访问元素，并搜索列表中的元素。
   /**
    * Add a ball to the panel.
    * @param b the ball to add
    */
   public void add(Ball b)
   {
      balls.add(b);
   }

   public void paintComponent(Graphics g)
   {
      Graphics2D g2 = (Graphics2D) g;
      for (Ball b : balls)
      {
         g2.fill(b.getShape());
      }
   }
   
   public Dimension getPreferredSize() { return new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT); }
}

package bounce;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

/**
 * Shows an animated bouncing ball.
 * @version 1.34 2015-06-21
 * @author Cay Horstmann
 */
public class Bounce
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(() -> {
         JFrame frame = new BounceFrame();
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.setVisible(true);
      });
   }
}

/**
 * The frame with ball component and buttons.
 */
class BounceFrame extends JFrame
{
   private BallComponent comp;
   public static final int STEPS = 1000;
   public static final int DELAY = 3;

   /**
    * Constructs the frame with the component for showing the bouncing ball and
    * Start and Close buttons
    */
   public BounceFrame()
   {
      setTitle("Bounce");
      comp = new BallComponent();
      add(comp, BorderLayout.CENTER);//将自建的swing组件放在居中的位置
      JPanel buttonPanel = new JPanel();
      addButton(buttonPanel, "Start", event -> addBall());
      addButton(buttonPanel, "Close", event -> System.exit(0));//将两个组件注册为事件源并添加到buttonpanel中
      add(buttonPanel, BorderLayout.SOUTH);//将一个buttonpanel放到框架的南端
      pack();
   }

   /**
    * Adds a button to a container.
    * @param c the container
    * @param title the button title
    * @param listener the action listener for the button
    */
   public void addButton(Container c, String title, ActionListener listener)
   {
      JButton button = new JButton(title);
      c.add(button);
      button.addActionListener(listener);
   }//用addbutton方法将两个按钮组合为一个整体

   /**
    * Adds a bouncing ball to the panel and makes it bounce 1,000 times.
    */
   public void addBall()
   {
       
     try
      {
         Ball ball = new Ball();
         comp.add(ball);

         for (int i = 1; i <= STEPS; i++)
         {
            ball.move(comp.getBounds());
            comp.paint(comp.getGraphics());
            Thread.sleep(DELAY);//调用sleep并未创建线程对象，只是为了将两个球的轨迹可以显示出来
         }
      }
      catch (InterruptedException e)
      {
      }
   }
}

package bounceThread;

import java.awt.*;
import java.awt.event.*;

import javax.swing.*;

/**
 * Shows animated bouncing balls.
 * @version 1.34 2015-06-21
 * @author Cay Horstmann
 */
public class BounceThread
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(() -> {
         JFrame frame = new BounceFrame();
         frame.setTitle("BounceThread");
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.setVisible(true);
      });
   }
}

/**
 * The frame with panel and buttons.
 */
class BounceFrame extends JFrame
{
   private BallComponent comp;
   public static final int STEPS = 1000;
   public static final int DELAY = 5;


   /**
    * Constructs the frame with the component for showing the bouncing ball and
    * Start and Close buttons
    */
   public BounceFrame()
   {
      comp = new BallComponent();
      add(comp, BorderLayout.CENTER);
      JPanel buttonPanel = new JPanel();
      addButton(buttonPanel, "Start", event -> addBall());
      addButton(buttonPanel, "Close", event -> System.exit(0));
      add(buttonPanel, BorderLayout.SOUTH);
      pack();
   }

   /**
    * Adds a button to a container.
    * @param c the container
    * @param title the button title
    * @param listener the action listener for the button
    */
   public void addButton(Container c, String title, ActionListener listener)
   {
      JButton button = new JButton(title);
      c.add(button);
      button.addActionListener(listener);
   }

   /**
    * Adds a bouncing ball to the canvas and starts a thread to make it bounce
    */
   public void addBall()
   {
      Ball ball = new Ball();
      comp.add(ball);
      Runnable r = () -> { //使用匿名内部类
         try
         {  
            for (int i = 1; i <= STEPS; i++)
            {
               ball.move(comp.getBounds());
               comp.repaint();
               Thread.sleep(DELAY);
            }
         }
         catch (InterruptedException e)
         {
         }
      };
      Thread t = new Thread(r);
      t.start();//使得小球的移动成为其中的一个子线程
   }
}

 1 package synch;
 2 
 3 import java.util.*;
 4 import java.util.concurrent.locks.*;
 5 
 6 /**
 7  * A bank with a number of bank accounts that uses locks for serializing access.
 8  * @version 1.30 2004-08-01
 9  * @author Cay Horstmann
10  */
11 public class Bank
12 {
13    private final double[] accounts;
14    private Lock bankLock;
15    private Condition sufficientFunds;
16 
17    /**
18     * Constructs the bank.
19     * @param n the number of accounts
20     * @param initialBalance the initial balance for each account
21     */
22    public Bank(int n, double initialBalance)
23    {
24       accounts = new double[n];
25       Arrays.fill(accounts, initialBalance);//将指定的 double 值分配给指定 double 型数组的每个元素
26       bankLock = new ReentrantLock();
27       sufficientFunds = bankLock.newCondition();//返回绑定到此 Lock 实例的新 Condition 实例
28    }
29 
30    /**
31     * Transfers money from one account to another.
32     * @param from the account to transfer from
33     * @param to the account to transfer to
34     * @param amount the amount to transfer
35     */
36    public void transfer(int from, int to, double amount) throws InterruptedException
37    {
38       bankLock.lock();//获取锁
39       try
40       {
41          while (accounts[from] < amount)
42             sufficientFunds.await();//造成当前线程在接到信号或被中断之前一直处于等待状态
43          System.out.print(Thread.currentThread());
44          accounts[from] -= amount;
45          System.out.printf(" %10.2f from %d to %d", amount, from, to);
46          accounts[to] += amount;
47          System.out.printf(" Total Balance: %10.2f%n", getTotalBalance());
48          sufficientFunds.signalAll();//唤醒所有等待线程
49       }
50       finally
51       {
52          bankLock.unlock();//释放锁
53       }
54    }
55 
56    /**
57     * Gets the sum of all account balances.
58     * @return the total balance
59     */
60    public double getTotalBalance()
61    {
62       bankLock.lock();
63       try
64       {
65          double sum = 0;
66 
67          for (double a : accounts)
68             sum += a;
69 
70          return sum;
71       }
72       finally
73       {
74          bankLock.unlock();
75       }
76    }
77 
78    /**
79     * Gets the number of accounts in the bank.
80     * @return the number of accounts
81     */
82    public int size()
83    {
84       return accounts.length;
85    }
86 }

 1 package synch;
 2 
 3 /**
 4  * This program shows how multiple threads can safely access a data structure.
 5  * @version 1.31 2015-06-21
 6  * @author Cay Horstmann
 7  */
 8 public class SynchBankTest
 9 {
10    public static final int NACCOUNTS = 100;
11    public static final double INITIAL_BALANCE = 1000;
12    public static final double MAX_AMOUNT = 1000;
13    public static final int DELAY = 10;
14    
15    public static void main(String[] args)
16    {
17       Bank bank = new Bank(NACCOUNTS, INITIAL_BALANCE);
18       for (int i = 0; i < NACCOUNTS; i++)
19       {
20          int fromAccount = i;
21          Runnable r = () -> {//用Lambda表达式简化代码
22             try
23             {
24                while (true)
25                {
26                   int toAccount = (int) (bank.size() * Math.random());
27                   double amount = MAX_AMOUNT * Math.random();
28                   bank.transfer(fromAccount, toAccount, amount);
29                   Thread.sleep((int) (DELAY * Math.random()));
30                }
31             }
32             catch (InterruptedException e)
33             {
34             }            
35          };
36          Thread t = new Thread(r);
37          t.start();
38       }
39    }
40 }

package project2;

class Lefthand extends Thread { 

       public void run()

       {

           for(int i=0;i<=4;i++)

           {  System.out.println("1.你好");

               try{   sleep(500);   }

               catch(InterruptedException e)

               { System.out.println("Lefthand error.");}    

           } 

      } 

    }

    class Righthand extends Thread {

        public void run()

        {

             for(int i=0;i<=4;i++)

             {   System.out.println("2.你好");

                 try{  sleep(300);  }

                 catch(InterruptedException e)

                 { System.out.println("Righthand error.");}

             }

        }

    }

    public class ThreadText 

    {

         static Lefthand left;

         static Righthand right;

         public static void main(String[] args)

         {     left=new Lefthand();

               right=new Righthand();

               left.start();

               right.start();

         }

    }