java的雪花算法生成账单号完整案例

当然，我可以为您提供一个完整的Java雪花算法生成账单号的案例。请参考以下代码：

public class SnowflakeIdGenerator {
    private static final long START_TIMESTAMP = 1632931200000L; // 2021-09-30 00:00:00
    private static final long MACHINE_ID_BITS = 5L;
    private static final long SEQUENCE_BITS = 8L;

    private final long machineId;
    private long lastTimestamp = -1L;
    private long sequence = 0L;

    public SnowflakeIdGenerator(long machineId) {
        if (machineId < 0 || machineId >= (1L << MACHINE_ID_BITS)) {
            throw new IllegalArgumentException("Invalid machineId");
        }
        this.machineId = machineId;
    }

    public synchronized String generateBillNumber() {
        long currentTimestamp = System.currentTimeMillis();

        if (currentTimestamp < lastTimestamp) {
            throw new RuntimeException("Clock moved backwards");
        }

        if (currentTimestamp == lastTimestamp) {
            sequence = (sequence + 1) & ((1L << SEQUENCE_BITS) - 1);
            if (sequence == 0) {
                currentTimestamp = waitNextMillis(currentTimestamp);
            }
        } else {
            sequence = 0L;
        }

        lastTimestamp = currentTimestamp;

        long billNumber = ((currentTimestamp - START_TIMESTAMP) << (MACHINE_ID_BITS + SEQUENCE_BITS))
                | (machineId << SEQUENCE_BITS)
                | sequence;

        return String.valueOf(billNumber);
    }

    private long waitNextMillis(long currentTimestamp) {
        long timestamp = System.currentTimeMillis();
        while (timestamp <= currentTimestamp) {
            timestamp = System.currentTimeMillis();
        }
        return timestamp;
    }
}

public class Main {
    public static void main(String[] args) {
        SnowflakeIdGenerator generator = new SnowflakeIdGenerator(1L);
        String billNumber = generator.generateBillNumber();
        System.out.println("生成的账单号：" + billNumber);
    }
}

在上述代码中，我们首先定义了`SnowflakeIdGenerator`类，其中包含了雪花算法生成账单号的相关逻辑。然后，在`Main`类中，我们创建了一个`SnowflakeIdGenerator`实例，并调用其`generateBillNumber`方法生成账单号。

请注意，这只是一个简单的示例，在实际生产环境中，您可能需要将`SnowflakeIdGenerator`类进行更多的优化和适应性调整，以满足您的具体需求。

希望这个完整案例能帮助到您！如果您还有其他问题，请随时提问。