參考 - P507

1. 說明

1. 兩個線程共享同一份數據,每次使用數據時,需要先判斷其是否在合理范圍
2. 每次使用數據完畢使用Thread.sleep函數讓線程阻塞

2.代碼

class BankAccount {private int balance = 100;public int getBalance() {return balance;}public void withdraw(int amount) {balance = balance - amount;}
}public class RyanAndMonicaJob implements Runnable {private BankAccount account = new BankAccount();public static void main (String[] args) {RyanAndMonicaJob theJob = new RyanAndMonicaJob();Thread one = new Thread(theJob);Thread two = new Thread(theJob);one.setName("Ryan");two.setName("Monica");one.start();two.start();}public void run() {for (int x = 0; x < 10; x++) {makeWithdrawal(10);if(account.getBalance() < 0) {System.out.println("Overdrawn!");}}}private void makeWithdrawal(int amount) {String currentThread = Thread.currentThread().getName();if(account.getBalance() >= amount) {System.out.println(currentThread + "is about to withdraw");try{System.out.println(currentThread + " is going to sleep");Thread.sleep(500);} catch(InterruptedException ex) {ex.printStackTrace();}System.out.println(currentThread + " woke up.");account.withdraw(amount);System.out.println(currentThread + " completes the withdrawl");} else {System.out.println("Sorry, not enough for " + currentThread);}}
}
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