解决 JPA2.1 支持 group by 多个字段

可以使用 Hibernate API 中的 @Formula 解决 group by 中多个字段的问题，代码如下：

maven 依赖

        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>5.0.12.Final</version>
            <exclusions>
                <exclusion>
                    <groupId>org.apache.geronimo.specs</groupId>
                    <artifactId>geronimo-jta_1.1_spec</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-entitymanager</artifactId>
            <version>5.0.12.Final</version>
            <exclusions>
                <exclusion>
                    <groupId>org.apache.geronimo.specs</groupId>
                    <artifactId>geronimo-jta_1.1_spec</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

entity 对象中添加 concat 属性

    @Formula("concat(date, receive_way)")
    private String concated;

repo 中基于 concated 字段进行分组

        JPAQuery<?> query = new JPAQuery<Void>(em);
        QSettleAccount settleAccount = QSettleAccount.settleAccount;

        return query.select(
                settleAccount.date,
                settleAccount.receiveWay,
                settleAccount.settleAmount.sum(),
                settleAccount.procedureFee.sum())
                .from(settleAccount)
                .groupBy(settleAccount.concated)
                .having(predicate)
                .offset(0)
                .limit(10)
                .fetchResults();

以上方式已经验证通过