201771010126 王燕《面向对象程序设计（Java）》第十七周学习总结

 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 = () -> {
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 }

 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);
26       bankLock = new ReentrantLock();
27       sufficientFunds = bankLock.newCondition();
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();
39       try
40       {
41          while (accounts[from] < amount)
42             sufficientFunds.await();
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();
49       }
50       finally
51       {
52          bankLock.unlock();
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 synch2;
 2 
 3 import java.util.*;
 4 
 5 /**
 6  * A bank with a number of bank accounts that uses synchronization primitives.
 7  * @version 1.30 2004-08-01
 8  * @author Cay Horstmann
 9  */
10 public class Bank
11 {
12    private final double[] accounts;
13 
14    /**
15     * Constructs the bank.
16     * @param n the number of accounts
17     * @param initialBalance the initial balance for each account
18     */
19    public Bank(int n, double initialBalance)
20    {
21       accounts = new double[n];
22       Arrays.fill(accounts, initialBalance);
23    }
24 
25    /**
26     * Transfers money from one account to another.
27     * @param from the account to transfer from
28     * @param to the account to transfer to
29     * @param amount the amount to transfer
30     */
31    public synchronized void transfer(int from, int to, double amount) throws InterruptedException
32    {
33       while (accounts[from] < amount)
34          wait();
35       System.out.print(Thread.currentThread());
36       accounts[from] -= amount;
37       System.out.printf(" %10.2f from %d to %d", amount, from, to);
38       accounts[to] += amount;
39       System.out.printf(" Total Balance: %10.2f%n", getTotalBalance());
40       notifyAll();
41    }
42 
43    /**
44     * Gets the sum of all account balances.
45     * @return the total balance
46     */
47    public synchronized double getTotalBalance()
48    {
49       double sum = 0;
50 
51       for (double a : accounts)
52          sum += a;
53 
54       return sum;
55    }
56 
57    /**
58     * Gets the number of accounts in the bank.
59     * @return the number of accounts
60     */
61    public int size()
62    {
63       return accounts.length;
64    }
65 }

 1 package synch2;
 2 
 3 import java.util.*;
 4 
 5 /**
 6  * A bank with a number of bank accounts that uses synchronization primitives.
 7  * @version 1.30 2004-08-01
 8  * @author Cay Horstmann
 9  */
10 public class Bank
11 {
12    private final double[] accounts;
13 
14    /**
15     * Constructs the bank.
16     * @param n the number of accounts
17     * @param initialBalance the initial balance for each account
18     */
19    public Bank(int n, double initialBalance)
20    {
21       accounts = new double[n];
22       Arrays.fill(accounts, initialBalance);
23    }
24 
25    /**
26     * Transfers money from one account to another.
27     * @param from the account to transfer from
28     * @param to the account to transfer to
29     * @param amount the amount to transfer
30     */
31    public synchronized void transfer(int from, int to, double amount) throws InterruptedException
32    {
33       while (accounts[from] < amount)
34          wait();
35       System.out.print(Thread.currentThread());
36       accounts[from] -= amount;
37       System.out.printf(" %10.2f from %d to %d", amount, from, to);
38       accounts[to] += amount;
39       System.out.printf(" Total Balance: %10.2f%n", getTotalBalance());
40       notifyAll();
41    }
42 
43    /**
44     * Gets the sum of all account balances.
45     * @return the total balance
46     */
47    public synchronized double getTotalBalance()
48    {
49       double sum = 0;
50 
51       for (double a : accounts)
52          sum += a;
53 
54       return sum;
55    }
56 
57    /**
58     * Gets the number of accounts in the bank.
59     * @return the number of accounts
60     */
61    public int size()
62    {
63       return accounts.length;
64    }
65 }

 1 package synch3;
 2 class Cbank
 3 {
 4      private static int s=2000;
 5      public synchronized  static void sub(int m)
 6      {
 7            int temp=s;
 8            temp=temp-m;
 9           try {
10       Thread.sleep((int)(1000*Math.random()));
11     }
12            catch (InterruptedException e)  {              }
13            s=temp;
14            System.out.println("s="+s);
15    }
16 }
17 class Customer extends Thread
18 {
19   public void run()
20   {
21    for( int i=1; i<=4; i++)
22      Cbank.sub(100);
23     }
24  }
25 public class Thread3
26 {
27  public static void main(String args[])
28   {
29    Customer customer1 = new Customer();
30    Customer customer2 = new Customer();
31    customer1.start();
32    customer2.start();
33   }
34 }

 1 package shoupiao;
 2 public class Ticket implements Runnable {
 3     public int num = 0;     
 4     Object obj = new Object();
 5     public void run() {
 6         while (true) {
 7             // 关键字后的小括号表示锁，锁可以是程序中的任意一个对象
 8             synchronized (obj) {
 9                 if (num >= 10) { //系统默认测试数据10张车票
10                      break;
11                 }
12                  try {
13                     // 当线程睡眠时锁不会开
14                    Thread.sleep(50);
15                 } catch (InterruptedException e) {
16                     e.printStackTrace();
17                }
18                num++;
19                 if(num<10){
20                     System.out.println(Thread.currentThread().getName() + "第"+num+"张票" );
21                 }else{
22                     System.out.println(Thread.currentThread().getName() + "第"+num+"张票" );
23                 }
24             }
25         }
26     }
27     public static void main(String[] args) {
28         Ticket ticket = new Ticket();
29         //1.创建购票线程 
30         Thread t1 = new Thread(ticket, "Thread-0窗口售：");
31         Thread t2 = new Thread(ticket, "Thread-1窗口售：");
32         Thread t3 = new Thread(ticket, "Thread-2窗口售：");
33         //2.开启购票点（模拟3个线程）测试购票      
34         System.out.println("---------------------------------");
35         System.out.println("售票系统");
36         System.out.println("---------------------------------");
37         System.out.println("系统当前在线剩余总票数：10张");
38         t1.start();
39         t2.start();
40         t3.start();
41     }
42  }