RowMapper奇怪的结果

Question

我正在使用JdbcTemplate查询数据库的Spring应用程序，并且rowmapper的结果与查询的结果不同。

我的查询返回：

+--------------------+---------+------+------+----------+----------+----------+----------+---------+----------------+-----------------+
| ORIGINATING_SYSTEM | SYS_REF | CUR1 | CUR2 | TRADE_DT | START_DT |  END_DT  | BOOK_REF | BOOK_ID |    NOMINAL     | ORIGIN_VALUE_DT |
+--------------------+---------+------+------+----------+----------+----------+----------+---------+----------------+-----------------+
| CC                 | 4000000 | USD  |      | 01/04/19 | 01/04/19 | 01/04/19 | TDCZK    |     317 | -8245872154,55 | 29/03/19        |
| GPS                | 4000000 | EUR  |      | 01/04/19 | 28/03/19 | 28/03/19 | TDCZK    |     317 |       55555550 |                 |
+--------------------+---------+------+------+----------+----------+----------+----------+---------+----------------+-----------------+

此结果由rowmapper处理以获取列表：

public List<Trade> findBackValueTrades() {
    List<Trade> trades = getJdbcTemplate().query(FIND_BACK_VALUE_TRADES, new BackValueTradeMapper());
}

class BackValueTradeMapper implements RowMapper<Trade> {

    public BackValueTradeMapper() {
    }

    @Override
    public Trade mapRow(final ResultSet rs, final int rowNum) throws SQLException {

        Trade trade = new Trade();

        trade.setOriginatingSystem(rs.getString("ORIGINATING_SYSTEM"));
        trade.setSystemRef(rs.getString("SYS_REF"));
        trade.setNominal(rs.getDouble("NOMINAL"));
        Currency cur1 = new Currency();
        cur1.setId(rs.getString("CUR1"));
        trade.setCurrency1(cur1);
        Currency cur2 = new Currency();
        cur2.setId(rs.getString("CUR2"));
        trade.setCurrency2(cur2);
        trade.setTradeDate(rs.getDate("TRADE_DT"));
        trade.setStartDate(rs.getDate("START_DT"));
        trade.setEndDate(rs.getDate("END_DT"));
        Book book = new Book();
        book.setBookRef(rs.getString("BOOK_REF"));
        book.setId(rs.getLong("BOOK_ID"));
        trade.setBook(book);
        trade.setNominal(rs.getDouble("NOMINAL"));
        trade.setEnteredDate(rs.getDate("ORIGIN_VALUE_DT"));
        return trade;
    }
}

其中贸易只是@Entity，仅包含字段，获取器和设置器：

@Table(name = "TRADES")
@Entity
public class Trade implements Serializable {

    private static final long serialVersionUID = 2143115773381859155L;

    @Column(name = "ID")
    @Id
    private Long id;

    @Column(name = "SYS_REF")
    private String systemRef;

    @Column(name = "ORIGINATING_SYSTEM")
    private String originatingSystem;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "CUR1")
    private Currency cur1;

    // remaining fields + getters/setters
}

问题出在结果列表中，似乎CC的交易被覆盖了：

+--------------------+---------+------+------+----------+----------+----------+----------+---------+-----------+-----------------+
| ORIGINATING_SYSTEM | SYS_REF | CUR1 | CUR2 | TRADE_DT | START_DT |  END_DT  | BOOK_REF | BOOK_ID |  NOMINAL  | ORIGIN_VALUE_DT |
+--------------------+---------+------+------+----------+----------+----------+----------+---------+-----------+-----------------+
| GPS                | 4000000 | EUR  |      | 01/04/19 | 28/03/19 | 28/03/19 | TDCZK    |     317 |  55555550 | 29/03/19        |
| GPS                | 4000000 | EUR  |      | 01/04/19 | 28/03/19 | 28/03/19 | TDCZK    |     317 |  55555550 | 28/03/19        |
+--------------------+---------+------+------+----------+----------+----------+----------+---------+-----------+-----------------+

那是为什么？

顺便说一句，我能够通过扩展Trade类并覆盖equals和hashCode来解决此问题，但是我想知道它为什么起作用。