Java多线程：同步和死锁示例-蒲公英云

Java多线程：同步和死锁示例

原创迈不过友情╰ 2024-10-10 12:36 145阅读 0赞

在Java编程中，多线程可以通过synchronized关键字实现同步机制。同时，死锁是多线程中的一个严重问题。下面我们将通过两个示例来理解这些概念。

示例1：使用`synchronized`实现简单同步

public class Counter {
    private int count = 0;
    public synchronized void increment() {
        count++;
    }
    public synchronized int decrement() {
        if (count > 0) {
            count--;
            return count;
        } else {
            throw new RuntimeException("Cannot decrement from zero");
        }
    }
    // Getter for count
    public synchronized int getCount() {
        return count;
    }
}

在这个示例中，我们创建了一个Counter类，其中包含了共享的计数器。我们通过synchronized关键字确保同一时刻只有一个线程可以访问这些方法。

示例2：死锁的产生

public class BankAccount {
    private String accountNumber;
    private double balance;
    public synchronized void deposit(double amount) {
        if (amount > 0) {
            balance += amount;
        }
    }
    // Getter for balance
    public synchronized double getBalance() {
        return balance;
    }
    // Getter for account number
    public synchronized String getAccountNumber() {
        return accountNumber;
    }
    // Method to transfer money between accounts
    public synchronized void transferMoney(String recipientAccount, double amount) throws InsufficientFundsException {
        if (accountNumber != null && recipientAccount != null) {
            // Check sender's balance
            double senderBalance = getBalance();
            if (amount > senderBalance) {
                throw new InsufficientFundsException("Insufficient funds to transfer " + amount);
            }
            // Transfer money
            balance -= amount;
            System.out.println("Money transferred from account " + this.getAccountNumber() + " to account " + recipientAccount + ". Amount transferred: " + amount);
            // Check receiver's balance
            double receiverBalance = getRecipientBankAccount().getBalance();
            if (receiverBalance + amount < 0) {
                throw new InsufficientFundsException("Receiver's balance insufficient after transfer. Amount remaining: " + (-receiverBalance - amount)));
            }
        } else {
            throw new IllegalArgumentException("Invalid account number or recipient account");
        }
    }
}