201771010137赵栋《面向对象程序设计（java）》第十七周学习总结(代码片段)

package synch;

import java.util.*;
import java.util.concurrent.locks.*;

/**
 * 一种拥有许多银行帐户的银行，它使用锁来序列化访问。
 * @version 1.30 2004-08-01
 * @author Cay Horstmann
 */
public class Bank

   private final double[] accounts;
   private Lock bankLock;
   private Condition sufficientFunds;

   /**
    *构建了银行。
    * @param 账户数量
    * @param 每个账户的初始余额
    */
   public Bank(int n, double initialBalance)
   
      accounts = new double[n];
      Arrays.fill(accounts, initialBalance);
      bankLock = new ReentrantLock();
      sufficientFunds = bankLock.newCondition();
   

   /**
    * 把钱从一个账户转到另一个账户。
    * @param 从账户转出
    * @param 到账转到
    * @param 转帐金额
    */
   public void transfer(int from, int to, double amount) throws InterruptedException
   
      bankLock.lock();
      try
      
         while (accounts[from] < amount)
         sufficientFunds.await();//注释掉之后产生死锁现象，都在等待
         System.out.print(Thread.currentThread());
         accounts[from] -= amount;
         System.out.printf(" %10.2f from %d to %d", amount, from, to);
         accounts[to] += amount;
         System.out.printf(" Total Balance: %10.2f%n", getTotalBalance());
         sufficientFunds.signalAll();//注释掉之后产生死锁现象，都在等待
      
      finally
      
         bankLock.unlock();
      
   

   /**
    *获取所有帐户余额的总和。
    * @return 总平衡
    */
   public double getTotalBalance()//为什么只需要加锁不需要设置对象？没有任何执行不下去的原因，就不需要条件对象。
   
      bankLock.lock();
      try
      
         double sum = 0;

         for (double a : accounts)
            sum += a;

         return sum;
      
      finally
      
         bankLock.unlock();
      
   

   /**
    * 获取银行中的帐户编号。
    * @return 账户数量
    */
   public int size()
   
      return accounts.length;
   

package synch;
/**
 * 这个程序展示了多线程如何安全地访问数据结构。
 * @version 1.31 2015-06-21
 * @author Cay Horstmann
 */
public class SynchBankTest

   public static final int NACCOUNTS = 100;
   public static final double INITIAL_BALANCE = 1000;
   public static final double MAX_AMOUNT = 1000;
   public static final int DELAY = 10;
   
   public static void main(String[] args)
   
      Bank bank = new Bank(NACCOUNTS, INITIAL_BALANCE);
      for (int i = 0; i < NACCOUNTS; i++)
      
         int fromAccount = i;
         Runnable r = () -> 
            try
            
               while (true)
               
                  int toAccount = (int) (bank.size() * Math.random());
                  double amount = MAX_AMOUNT * Math.random();
                  bank.transfer(fromAccount, toAccount, amount);
                  Thread.sleep((int) (DELAY * Math.random()));
               
            
            catch (InterruptedException e)
            
                        
         ;
         Thread t = new Thread(r);
         t.start();
      
   

package synch2;

import java.util.*;

/**
 * 使用同步原语的具有多个银行帐户的银行
 * @version 1.30 2004-08-01
 * @author Cay Horstmann
 */
public class Bank

   private final double[] accounts;

   /**
    * 构建了银行。
    * @param  账户数量
    * @param 每个账户的初始余额
    */
   public Bank(int n, double initialBalance)
   
      accounts = new double[n];
      Arrays.fill(accounts, initialBalance);
   

   /**
    * 把钱从一个账户转到另一个账户。
    * @param 从账户转出
    * @param 到账转到
    * @param 转帐金额
    */
   public synchronized void transfer(int from, int to, double amount) throws InterruptedException
   
      while (accounts[from] < amount)
         wait();//Object类
      System.out.print(Thread.currentThread());
      accounts[from] -= amount;
      System.out.printf(" %10.2f from %d to %d", amount, from, to);
      accounts[to] += amount;
      System.out.printf(" Total Balance: %10.2f%n", getTotalBalance());
      notifyAll();
   
   /**
    *获取所有帐户余额的总和。
    * @return 总平衡
    */
   public synchronized double getTotalBalance()
   
      double sum = 0;

      for (double a : accounts)
         sum += a;

      return sum;
   

   /**
    * 获取银行中的帐户编号。
    * @return 账户数量
    */
   public int size()
   
      return accounts.length;
   

package synch2;

/**
 * 这个程序展示了多线程如何安全地访问一个数据结构，使用同步方法。
 * @version 1.31 2015-06-21
 * @author Cay Horstmann
 */
public class SynchBankTest2

   public static final int NACCOUNTS = 100;
   public static final double INITIAL_BALANCE = 1000;
   public static final double MAX_AMOUNT = 1000;
   public static final int DELAY = 10;

   public static void main(String[] args)
   
      Bank bank = new Bank(NACCOUNTS, INITIAL_BALANCE);
      for (int i = 0; i < NACCOUNTS; i++)
      
         int fromAccount = i;
         Runnable r = () -> 
            try
            
               while (true)
               
                  int toAccount = (int) (bank.size() * Math.random());
                  double amount = MAX_AMOUNT * Math.random();
                  bank.transfer(fromAccount, toAccount, amount);
                  Thread.sleep((int) (DELAY * Math.random()));
               
            
            catch (InterruptedException e)
            
            
         ;
         Thread t = new Thread(r);
         t.start();
      
   

import javax.sql.rowset.spi.SyncFactory;

class Cbank

     private static int s=2000;
     public synchronized static void sub(int m)
     
           int temp=s;
           temp=temp-m;
          try 
                 Thread.sleep((int)(1000*Math.random()));
               
           catch (InterruptedException e)                
              s=temp;
              System.out.println("s="+s);
          
    


class Customer extends Thread

  public void   run()
  
   for( int i=1; i<=4; i++)
    Cbank.sub(100);
    
 
public class Thread3

 public static void main(String args[])
  
   Customer customer1 = new Customer();
   Customer customer2 = new Customer();
   customer1.start();
   customer2.start();
  

public class Demo 
    public static void main(String[] args) 
        Mythread mythread = new Mythread();
        Thread ticket1 = new Thread(mythread);
        Thread ticket2 = new Thread(mythread);
        Thread ticket3 = new Thread(mythread);
        ticket1.start();
        ticket2.start();
        ticket3.start();
    


class Mythread implements Runnable 
    int ticket = 1;
    boolean flag = true;

    @Override
    public void run() 
        while (flag) 
            try 
                Thread.sleep(500);
             catch (InterruptedException e) 
                // TODO Auto-generated catch block
                e.printStackTrace();
            

            synchronized (this) 
                if (ticket <= 10) 
                    System.out.println(Thread.currentThread().getName() + "窗口售：第" + ticket + "张票");
                    ticket++;
                
                if (ticket > 10) 
                    flag = false;