分表时保留多基因

比如需要分片的表：
public class Transaction {

@Id
@Column(name = "transaction_id")
private String transactionId;

@Column(name = "source_account")
private String sourceAccount;

@Column(name = "target_account")
private String targetAccount;
private BigDecimal amount;
private OffsetDateTime timestamp;

}

现在希望根据sourceAccount+targetAccount+timestamp 生成唯一不重复的transactionId，然后根据transactionId取模进行分片，并且根据sourceAccount或者targetAccount能快速找到分片

import java.time.Instant;
import java.time.OffsetDateTime;
import java.time.ZoneOffset;
import java.util.UUID;

public class TransactionIdGenerator {
    private static final int SHARD_COUNT = 16; // 假设 16 个分片

    public static String generateId(String sourceAccount, String targetAccount, OffsetDateTime timestamp) {
        long ts = timestamp.toInstant().toEpochMilli();
        int sourceHash = Math.abs(sourceAccount.hashCode()) & 0xFFFF;
        int targetHash = Math.abs(targetAccount.hashCode()) & 0xFFFF;
        long uniquePart = UUID.randomUUID().getMostSignificantBits() & 0xFFFFFFFFFFFFL; //序列号可以用数据库来生成

        long id = ((ts << 48) |
                ((long) sourceHash << 32) |
                ((long) targetHash << 16) |
                uniquePart);

        return Long.toUnsignedString(id);
    }

    public static int getShardFromTransactionId(String transactionId) {
        long id = Long.parseUnsignedLong(transactionId);
        int sourceHash = (int) ((id >> 32) & 0xFFFF);
        int targetHash = (int) ((id >> 16) & 0xFFFF);
        // 合并 sourceHash 和 targetHash
        int combinedHash = sourceHash ^ targetHash;
        return combinedHash % SHARD_COUNT;
    }

public static int getShardFromSourceAccount(String sourceAccount) {
        int sourceHash = Math.abs(sourceAccount.hashCode()) & 0xFFFF;
        return sourceHash % SHARD_COUNT;
    }
}