Java多线程并发中资源竞争问题实例

原创系统管理员 2024-11-22 07:24 18阅读 0赞

在Java多线程并发编程中，资源竞争问题是一个常见的例子。这里以一个简单的银行账户转账系统为例：

1. **账户类** (Account.java)
```java
import java.util.Random;

public class Account {
    private double balance;
    private final Random rand = new Random();

public Account(double initialBalance) {
        this.balance = initialBalance;
    }

public void deposit(double amount) {
        balance += amount;
    }

public void withdraw(double amount) {
        if (amount > balance)
            throw new IllegalArgumentException("Insufficient funds.");

balance -= amount;
    }

// Generating random transactions
    public void transfer(Account toAccount, double amount) {
        // Transaction validation
        if (amount <= 0 || toAccount == null)
            return;

// Calculate source account's change after transaction
        double sourceChange = withdraw(amount);

// Update destination account balance and print result
        toAccount.deposit(sourceChange);
        System.out.println("Transfer successful: " + amount);
    }
}
```

2. **主程序** (Main.java)
```java
public class Main {
    public static void main(String[] args) {
        Account sourceAccount = new Account(100);
        Account destinationAccount = new Account(50);

// Transfer 50 units from source to destination account
        sourceAccount.transfer(destinationAccount, 50));

// Print remaining balance in each account
        System.out.println("Source Account Balance: " + sourceAccount.balance);
        System.out.println("Destination Account Balance: " + destinationAccount.balance);
    }
}
```

在这个例子中，存在资源竞争问题。当两个线程同时尝试对一个账户进行转账时，可能会导致账户余额错误或系统崩溃。

为了避免这种问题，开发者通常会采用锁、信号量、原子变量等同步原语来保护共享资源。