JAVA实验十

（一）学习总结
1.用思维导图对java多线程的学习内容进行总结。

2.下面是一个单线程实现的龟兔赛跑游戏。

public class TortoiseHareRace {
    public static void main(String[] args) {
        int totalStep = 10;
        int tortoiseStep = 0;
        int hareStep = 0;
        boolean[] flags = {true,false};
        System.out.println("龟兔赛跑开始了...");
        while(tortoiseStep < totalStep && hareStep < totalStep){
            tortoiseStep++;
            System.out.println("乌龟跑了"+tortoiseStep+"步...");
            boolean isHareSleep = flags[((int)(Math.random()*10))%2];
            if(isHareSleep){
                System.out.println("兔子睡着了zzzz");
            }else{
                hareStep += 2;
                System.out.println("兔子跑了"+hareStep+"步...");
            }
        }       
    }
}

阅读程序，采用实现Runnable接口的方式用多线程实现这个小游戏。下面给出主线程类，补充Tortoise线程类和Hare线程类。

public class TortoiseHareRace { 
    public static void main(String[] args) {
        Tortoise tortoise = new Tortoise(10);
        Hare hare = new Hare(10);
        Thread tortoiseThread = new Thread(tortoise);
        Thread hareThread = new Thread(hare);
        tortoiseThread.start();
        hareThread.start();
    }
}

---修改为：

class Tortoise implements Runnable {
    private int totalStep;
    private int tortoiseStep = 0;
    public Tortoise(int totalStep) {
        this.totalStep = totalStep;
    }
    public void run() {
        running();
    }
    private synchronized void running() {
        while (tortoiseStep < totalStep) {
            tortoiseStep++;
            System.out.println("乌龟爬了" + tortoiseStep + "步");
        }
    }
}
class Hare implements Runnable {
    private int totalStep;
    private int hareStep = 0;
    public Hare(int totalStep) {
        this.totalStep = totalStep;
    }
    private synchronized void running() {
        boolean[] flags = { true, false };
        while (hareStep < totalStep) {
            boolean isHareSleep = flags[((int) (Math.random() * 10)) % 2];
            if (isHareSleep) {
                System.out.println("兔子睡着了zzzz");
            } else {
                hareStep += 2;
                System.out.println("兔子跑了" + hareStep + "步");
            }
        }
    }
    public void run() {
        running();
    }
}

3.下面的程序是模拟了生产者——消费者问题，生产者生产10个数，消费者依次消费10个数，运行程序，看结果是否正常？存在什么问题？说明原因。使用synchronized,wait,notify解决程序出现的问题。写出修改的部分程序即可。

class Consumer implements Runnable {
    private Clerk clerk;
    public Consumer(Clerk clerk) {
        this.clerk = clerk;
    }
    public void run() {
        System.out.println("消费者开始消耗整数......");
        // 消耗10个整数
        for(int i = 1; i <= 10; i++) {
            try {
                // 等待随机时间
                Thread.sleep((int) (Math.random() * 3000));
            }
            catch(InterruptedException e) {
                e.printStackTrace();
            }              
            clerk.getProduct();// 从店员处取走整数
        }
    }
}
class Producer implements Runnable {
    private Clerk clerk;
    public Producer(Clerk clerk) {
        this.clerk = clerk;
    }
    public void run() {
        System.out.println( "生产者开始生产整数......");
        // 生产1到10的整数
        for(int product = 1; product <= 10; product++) {
            try {
                Thread.sleep((int) Math.random() * 3000);
            }
            catch(InterruptedException e) {
                e.printStackTrace();
            }
            clerk.setProduct(product); // 将产品交给店员
        }
    } 
}
public class ProductTest {
    public static void main(String[] args) {
        Clerk clerk = new Clerk();
        Thread consumerThread = new Thread(new Consumer(clerk)); 
        Thread producerThread = new Thread(new Producer(clerk)); 
        consumerThread.start(); 
        producerThread.start(); 
    }
}
class Clerk {
    private int product = -1; // -1 表示目前没有产品 
    // 这个方法由生产者呼叫
    public void setProduct(int product) {
        this.product = product; 
        System.out.printf("生产者设定 (%d)%n", this.product);      
    } 
    // 这个方法由消费者呼叫
    public int getProduct() {          
        int p = this.product; 
        System.out.printf("消费者取走 (%d)%n", this.product);      
        return p; 
    } 
}

---运行结果有误。程序没有同步
---修改为：

class Clerk {
private int product = -1; // -1 表示目前没有产品
private int p ;
// 这个方法由生产者呼叫
public synchronized void setProduct(int product) {
    if (this.product != -1) {
        try {
            super.wait();
        } catch (InterruptedException e) {
        e.printStackTrace();
        }
    }
    this.product = product;
    p = this.product;
    System.out.printf("生产者设定 (%d)%n", this.product);
    getProduct();
    try {
        Thread.sleep(300);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
    this.product = -1;
    super.notify();
}
// 这个方法由消费者呼叫
public synchronized int getProduct() {
    if (this.product == -1) {
        try {
            super.wait();
        }catch (InterruptedException e) {
    e.printStackTrace();
        }
    }
    try {
        Thread.sleep(300);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
    System.out.printf("消费者取走 (%d)%n", p);
    this.product = -1;
    super.notify();
    return this.product;
}

（二）实验总结
1.模拟三个老师同时分发80分作业，每个老师相当于一个线程。
2.模拟一个银行存款的程序。假设有两个储户都去银行往同一个账户进行存款，一次存100，每人存三次。要求储户每存一次钱，账户余额增加100，并在控制台输出当前账户的余额。
（三）代码托管

https://git.oschina.net/hebau_cs15/java_CS01wfy.git