如何在兩個線程之間共享數據

總

1，若是每一個線程執行的代碼相同，可使用同一個Runnable對象，這個Runnable對象中有那個共享數據，例如，賣票系統就能夠這麼作。 

2，若是每一個線程執行的代碼不一樣，這時候須要用不一樣的Runnable對象，例如，設計4個線程。其中兩個線程每次對j增長1，另外兩個線程對j每次減1，銀行存取款

每一個線程執行的代碼相同，可使用同一個Runnable對象

public class RunnalbleTest2 implements Runnable {
    private int threadCnt = 10;

    @Override
    public void run() {
        while (true) {
            if (threadCnt > 0) {
                System.out.println(Thread.currentThread().getName() + " 剩餘個數 " + threadCnt);
                threadCnt--;
                try {
                    Thread.sleep(30);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            } else {
                break;
            }
        }
    }

    public static void main(String[] args) {
        RunnalbleTest2 runnalbleTest2 = new RunnalbleTest2();
        new Thread(runnalbleTest2).start();
        new Thread(runnalbleTest2).start();
    }
}

結果

Thread-0 剩餘個數 10
Thread-1 剩餘個數 10
Thread-0 剩餘個數 8
Thread-1 剩餘個數 7
Thread-0 剩餘個數 6
Thread-1 剩餘個數 5
Thread-0 剩餘個數 4
Thread-1 剩餘個數 3
Thread-0 剩餘個數 2
Thread-1 剩餘個數 1

每一個線程執行的代碼不一樣，用不一樣的Runnable對象

#

public class Acount {
    private int money;
    Acount(int money) {
        this.money = money;
    }

    public synchronized void getMoney(int money) {
        while (this.money < money) {
            System.out.println("餘額不足");
            try {
                wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        try {
            Thread.sleep(500);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        this.money -= money;
        System.out.println("取出" + money + ",還剩" + this.money);
    }

    public synchronized void setMoney(int money) {
        try {
            Thread.sleep(500);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        this.money += money;
        System.out.println("新存入" + money + ",總額：" + this.money);
        notify();

    }

    public static void main(String[] args) {
        Acount acount = new Acount(0);
        Bank bank = new Bank(acount);
        Consumer consumer = new Consumer(acount);
        new Thread(bank).start();
        new Thread(consumer).start();

    }
}

#

import java.util.Random;

public class Bank implements Runnable{
    Acount acount;
    public Bank(Acount acount) {
        this.acount = acount;
    }

    @Override
    public void run() {
        while(true) {
            int random = (int)(Math.random() * 1000);
            acount.setMoney(random);
        }
    }
}

#

public class Consumer implements Runnable{
    Acount acount;

    Consumer(Acount acount) {
        this.acount = acount;
    }

    @Override
    public void run() {
        while (true) {
            int random = (int)(Math.random() * 1000);
            acount.getMoney(random);
        }
    }

}

結果

新存入442,總額：442
餘額不足
新存入196,總額：638
新存入815,總額：1453
取出534,還剩919
新存入402,總額：1321
取出719,還剩602
取出11,還剩591
....