如何使用 Spring Data JPA 正确外部化本机 SQL 查询

Question

我正试图摆脱我的 jpa-named-queries.properties，因为我觉得必须明确说明换行符很烦人。

因此，我想外部化我的原生 SQL 查询，但我无法做到，需要帮助。

GenericRecordRepository.java

public interface GenericRecordRepository extends JpaRepository<GenericRecord, Long> {

    ...

    @Query(nativeQuery = true)
    List<TransactionView> getTransactionListIncludingNull();

    ...

}

orm.xml

<named-query name="GenericRecord.getTransactionListIncludingNull">
    <query>
        SELECT ALL_DATES_CATEGORIES_MATRIX.CATEGORY, ALL_DATES_CATEGORIES_MATRIX.DATE, EXPENSES_BY_CATEGORY.AMOUNT
        FROM
        (
        -- Transaction list with expenses in € grouped by month and category
        SELECT CATEGORY, DATE_FORMAT(CAST(local_date as DATE), '%m-%Y') AS DATE, SUM(AMOUNT) AS AMOUNT
        FROM GENERIC_RECORD
        GROUP BY CATEGORY, DATE
        ) AS EXPENSES_BY_CATEGORY
        RIGHT JOIN
        (
        -- Categories and dates matrix
        SELECT *
        FROM
        (
        -- Dates where there was at least one expense
        SELECT DISTINCT DATE_FORMAT(CAST(local_date as DATE), '%m-%Y') AS DATE
        FROM GENERIC_RECORD
        ) AS DISTINCT_DATES
        CROSS JOIN
        (
        -- All categories
        SELECT DISTINCT CATEGORY
        FROM GENERIC_RECORD
        ) AS DISTINCT_CATEGORIES
        ) AS ALL_DATES_CATEGORIES_MATRIX
        ON
        EXPENSES_BY_CATEGORY.DATE = ALL_DATES_CATEGORIES_MATRIX.DATE AND
        EXPENSES_BY_CATEGORY.CATEGORY = ALL_DATES_CATEGORIES_MATRIX.CATEGORY
        ORDER BY CATEGORY, DATE ASC
    </query>
</named-query>

org.springframework.data.mapping.PropertyReferenceException: No property getTransactionListIncluding found for type GenericRecord! 时我收到此错误

我也尝试更改方法的名称，因为名称中的“Null”部分似乎被切断了，但没有任何区别

Answer 1

您应该修复一些时间：

• 文件orm.xml应该位于META-INF文件夹，你可以通过链接https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#jpa.query-methods.named-queries阅读
• 改变那个文件的内容，内容应该从entity-mappings标签开始：

<?xml version="1.0" encoding="UTF-8"?>
<entity-mappings xmlns="http://xmlns.jcp.org/xml/ns/persistence/orm" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                 xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence/orm http://xmlns.jcp.org/xml/ns/persistence/orm_2_1.xsd"
                 version="2.1">
                 ...
</entity-mappings>

• 检查查询类型：named-query标签用于HQL，named-native-query标签用于本地sql，第二个应提供result-class属性：

例子：

对于 HQL 查询：

<?xml version="1.0" encoding="UTF-8"?>
<entity-mappings xmlns="http://xmlns.jcp.org/xml/ns/persistence/orm" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                 xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence/orm http://xmlns.jcp.org/xml/ns/persistence/orm_2_1.xsd"
                 version="2.1">
    <named-query name="Customer.bauerUsers">
        <query>
            <![CDATA[
            select u from Customer u where u.lastName = 'Bauer'
            ]]>
        </query>
    </named-query>
</entity-mappings>

对于原生查询：

<?xml version="1.0" encoding="UTF-8"?>
<entity-mappings xmlns="http://xmlns.jcp.org/xml/ns/persistence/orm" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                 xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence/orm http://xmlns.jcp.org/xml/ns/persistence/orm_2_1.xsd"
                 version="2.1">
    <named-native-query name="Customer.bauerUsers" result-class="com.datajpa.entity.Customer">
        <query>
            <![CDATA[
            SELECT * FROM CUSTOMER WHERE LAST_NAME = 'Bauer'
            ]]>
        </query>
    </named-native-query>
</entity-mappings>

• repository方法的名字应该和orm.xml中的一样，@Query注解不是必须的：

public interface CustomerRepository extends CrudRepository<Customer, Long> {

    List<Customer> bauerUsers();
}

您的工作版本应如下所示：

---

public interface GenericRecordRepository extends JpaRepository<GenericRecord, Long> {

    List<TransactionView> getTransactionListIncludingNull();

}

文件orm.xml：

<?xml version="1.0" encoding="UTF-8"?>
<entity-mappings xmlns="http://xmlns.jcp.org/xml/ns/persistence/orm" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                 xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence/orm http://xmlns.jcp.org/xml/ns/persistence/orm_2_1.xsd"
                 version="2.1">
    <named-native-query name="GenericRecord.getTransactionListIncludingNull" result-class="<path_to_your_class>.TransactionView">
        <query>
            <![CDATA[
            SELECT ALL_DATES_CATEGORIES_MATRIX.CATEGORY, ALL_DATES_CATEGORIES_MATRIX.DATE, EXPENSES_BY_CATEGORY.AMOUNT
        FROM
        (
        -- Transaction list with expenses in € grouped by month and category
        SELECT CATEGORY, DATE_FORMAT(CAST(local_date as DATE), '%m-%Y') AS DATE, SUM(AMOUNT) AS AMOUNT
        FROM GENERIC_RECORD
        GROUP BY CATEGORY, DATE
        ) AS EXPENSES_BY_CATEGORY
        RIGHT JOIN
        (
        -- Categories and dates matrix
        SELECT *
        FROM
        (
        -- Dates where there was at least one expense
        SELECT DISTINCT DATE_FORMAT(CAST(local_date as DATE), '%m-%Y') AS DATE
        FROM GENERIC_RECORD
        ) AS DISTINCT_DATES
        CROSS JOIN
        (
        -- All categories
        SELECT DISTINCT CATEGORY
        FROM GENERIC_RECORD
        ) AS DISTINCT_CATEGORIES
        ) AS ALL_DATES_CATEGORIES_MATRIX
        ON
        EXPENSES_BY_CATEGORY.DATE = ALL_DATES_CATEGORIES_MATRIX.DATE AND
        EXPENSES_BY_CATEGORY.CATEGORY = ALL_DATES_CATEGORIES_MATRIX.CATEGORY
        ORDER BY CATEGORY, DATE ASC
            ]]>
        </query>
    </named-native-query>
</entity-mappings>

Answer 2

您没有在 JpaRepository 中使用标准 Spring Data 方法，例如 findById 或 deleteByName。 （在这些情况下，id 和 name 必须是 GenericRecord 类型中的属性。）

在您的情况下，getTransactionListIncludingNull() 方法是您在 JpaRepository 中定义的自定义方法。要在 JpaRepository 中使用自定义方法，您应该定义一个新接口和它的实现。我想你没有考虑到这一点。

有很多关于它的文章可以帮助你。 （例如。， https://www.baeldung.com/spring-data-jpa-method-in-all-repositories, Add Custom Method to JPARepository with Generics)