下面是一个简单的Java代码示例,演示了如何使用Saga模式实现柔性事务:
// 定义一个Saga事务
public class SagaTransaction {
private List<TransactionStep> steps;
public SagaTransaction() {
this.steps = new ArrayList<>();
}
public void addStep(TransactionStep step) {
steps.add(step);
}
public void execute() {
for (TransactionStep step : steps) {
try {
step.execute();
} catch (Exception e) {
// 发生异常时执行回滚操作
rollback();
throw e;
}
}
}
private void rollback() {
// 逆序执行每个步骤的回滚操作
for (int i = steps.size() - 1; i >= 0; i--) {
TransactionStep step = steps.get(i);
try {
step.rollback();
} catch (Exception e) {
// 处理回滚异常,可以记录日志或采取其他措施
}
}
}
}
// 定义一个Saga事务步骤
public interface TransactionStep {
void execute();
void rollback();
}
// 示例:转账操作的Saga事务步骤
public class TransferStep implements TransactionStep {
private Account fromAccount;
private Account toAccount;
private BigDecimal amount;
public TransferStep(Account fromAccount, Account toAccount, BigDecimal amount) {
this.fromAccount = fromAccount;
this.toAccount = toAccount;
this.amount = amount;
}
@Override
public void execute() {
fromAccount.withdraw(amount);
toAccount.deposit(amount);
}
@Override
public void rollback() {
toAccount.withdraw(amount);
fromAccount.deposit(amount);
}
}
// 示例:账户类
public class Account {
private String accountId;
private BigDecimal balance;
// 省略构造函数和其他方法
public void withdraw(BigDecimal amount) {
// 执行提款操作
// ...
}
public void deposit(BigDecimal amount) {
// 执行存款操作
// ...
}
}
// 在应用程序中创建Saga事务并执行
public class Application {
public static void main(String[] args) {
// 创建账户对象
Account fromAccount = new Account("A001", new BigDecimal("1000.00"));
Account toAccount = new Account("A002", new BigDecimal("500.00"));
// 创建Saga事务并添加步骤
SagaTransaction sagaTransaction = new SagaTransaction();
sagaTransaction.addStep(new TransferStep(fromAccount, toAccount, new BigDecimal("200.00")));
sagaTransaction.addStep(new TransferStep(toAccount, fromAccount, new BigDecimal("100.00")));
// 执行Saga事务
try {
sagaTransaction.execute();
System.out.println("事务执行成功");
} catch (Exception e) {
System.out.println("事务执行失败");
// 处理事务执行失败的情况
}
}
}