java - 在java中实现事务而不使用任何库(如@Transactional)

Question

我有一个简单的应用程序，它执行以下操作:-

1. 从一个账户提款
2. 存入另一个帐户

private void transfer(fromAccount,toAccount, amount){
    fromAccount.withdraw(amount);
    toAccount.deposit(amount);
}

如果不在事务上下文中运行，上述实现是相当危险的。如何在不使用任何库或@Transactional的情况下实现事务。

Answer 1

public class YourClass() { 

   private void transfer(fromAccount,toAccount, amount) {
       Account fromAccountObj = new Account(fromAccount);
       Account toAccountObj = new Account(toAccount);
       synchronized(fromAccountObj) { 
          fromAccount.withdraw(amount);
       }
       synchronized(toAccountObj) { 
          toAccount.deposit(amount);
       }
   }
}

public class Account {
   private String accountNumber;
   public Account(String accountNumber) {
       this.accountNumber = accountNumber;
   }

   @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Account account = (Account) o;
        return accountNumber.equals(account.accountNumber);
    }

    @Override
    public int hashCode() {
        return Objects.hash(accountNumber);
    }
}

确保您的 equals 和 hashcode 对于相同帐号的 n 个对象返回相同的值