一文读懂Java多线程背后的故事

　　public class BankAccount {

　　private int balance;

　　public synchronized void deposit(int amount) {

　　balance += amount;

　　}

　　public synchronized void withdraw(int amount) {

　　balance -= amount;

　　}

　　public synchronized int getBalance() {

　　return balance;

　　}

　　}

　　public class TransferTask implements Runnable {

　　private final BankAccount sourceAccount;

　　private final BankAccount targetAccount;

　　private final int amount;

　　public TransferTask(BankAccount sourceAccount, BankAccount targetAccount, int amount) {

　　this.sourceAccount = sourceAccount;

　　this.targetAccount = targetAccount;

　　this.amount = amount;

　　}

　　@Override

　　public void run() {

　　sourceAccount.withdraw(amount);

　　targetAccount.deposit(amount);

　　}

　　}

　　public class BankExample {

　　public static void main(String[] args) {

　　BankAccount account1 = new BankAccount();

　　BankAccount account2 = new BankAccount();

　　account1.deposit(1000);

　　TransferTask transferTask1 = new TransferTask(account1, account2, 500);

　　TransferTask transferTask2 = new TransferTask(account2, account1, 300);

　　Thread thread1 = new Thread(transferTask1);

　　Thread thread2 = new Thread(transferTask2);

　　thread1.start();

　　thread2.start();

　　try {

　　thread1.join();

　　thread2.join();

　　} catch (InterruptedException e) {

　　e.printStackTrace();

　　}

　　System.out.println("Account 1 balance: " + account1.getBalance());

　　System.out.println("Account 2 balance: " + account2.getBalance());

　　}

　　}