Java多线程同步问题：synchronized关键字应用案例

原创你的名字 2024-09-13 06:18 88阅读 0赞

在Java中，`synchronized`关键字用于实现多线程的互斥访问。以下是一些典型的`synchronized`应用案例：

1. 同一对象上的方法：
```java
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 IllegalArgumentException("Counter is already zero.");
        }
    }

// Getter method for read-only access
    public synchronized int getCount() {
        return count;
    }
}
```
2. 同一锁对象下的方法：
```java
public class BankAccount {
    private String accountNumber;
    private double balance;

private Lock lock = new ReentrantLock();

// Public methods with synchronized blocks
    public synchronized void deposit(double amount) {
        lock.lock();
        try {
            balance += amount;
        } finally {
            lock.unlock();
        }
    }

public synchronized void withdraw(double amount) throws InsufficientFundsException {
        lock.lock();
        try {
            if (balance >= amount) {
                balance -= amount;
            } else {
                throw new InsufficientFundsException("Insufficient funds to make withdrawal.");
            }
        } finally {
            lock.unlock();
        }
    }

// Getter methods
    public synchronized String getAccountNumber() {
        return accountNumber;
    }

public synchronized double getBalance() {
        return balance;
    }
}
```
以上案例展示了如何使用`synchronized`关键字来保证同一时间内只有一个线程访问共享资源。