Spring Boot + Java 11 + Mybatis: @Many 在注解方法中被忽略

Question

我是Mybatis新手，使用@Many获取数据时遇到问题

我有两个 class，第二个 class 的对象是第一个 class 对象的值 Set<>;

类是：

public class InformationObjectMergedWithCopyrights {

    private Long id;
    private String titleLt;
    private String accountingNumber;
    private String inventoryNumber;
    private Long referenceYear;
    private Long duration;
    private String propertyRights;

    private Set<BavicCredit> creditsList = new HashSet<>();
    
    getters/setters, constructor, toString...
}

public class BavicCredit {

    private Long id;
    private Long informationObjectId;
    private String bavicLabel;
    private String bavicRole;
    
        getters/setters, constructor, toString...
}

我有 sql 提供程序，它生成查询字符串：

public class InformationObjectSqlProvider {
    public String selectByInventoryNumberConditionAccountingNumber(InventoryNumberReportParamsDao reportParamsDao) {
        
        StringBuilder sql = new StringBuilder("SELECT " +
            "io.ID AS id, " +
            "io.TITLE_LT AS titleLt, " +
            "io.ACCOUNTING_NUMBER AS accountingNumber, " +
            "io.INVENTORY_NUMBER AS inventoryNumber, " +
            "io.REFERENCE_YEAR AS referenceYear, " +
            "io.DURATION AS duration, " +
            "cvt.NAME AS propertyRights  " +
            "FROM SCHEMA_ONE.INFORMATION_OBJECT io " +
            "INNER JOIN SCHEMA_ONE.COPYRIGHTS c ON c.INFORMATION_OBJECT_ID = io.ID " +
            "INNER JOIN SCHEMA_TWO.CLASSIFIER_VALUES cv2 ON c.PROPERTY_RIGHTS = cv2.CODE " +
            "INNER JOIN SCHEMA_TWO.CLASSIFIER_VALUE_TRANSLATIONS cvt ON cv2.ID = cvt.CLASSIFIER_VALUE_ID AND cvt.LANGUAGE_ID = 1 " +
            "WHERE io.INVENTORY_NUMBER = #{reportParamsDao.inventoryNumberCode} ORDER BY accountingNumber ASC");

        return sql.toString();
    }
}

最后，我创建了一个映射器：

@Mapper
public interface InformationObjectMapper {

    InformationObjectSqlProvider provider = new InformationObjectSqlProvider();


    @SelectProvider(type = InformationObjectSqlProvider.class, method = "selectByInventoryNumberConditionAccountingNumber")
    @Results(value = {
        @Result(property = "creditsList",
            column = "SCHEMA_ONE.INF_OBJ_CLASIFFIER.INFORMATION_OBJECT_ID",
            javaType = Set.class, many = @Many(select = "selectCredits"))
    })
    List<InformationObjectMergedWithCopyrights> selectByInventoryNumberConditionAccountingNumber(@Param("reportParamsDao") InventoryNumberReportParamsDao reportParamsDao);

    @Select("SELECT * FROM SCHEMA_ONE.INF_OBJ_CLASSIFIER ioc WHERE ioc.INFORMATION_OBJECT_ID = #{informationObjetId} AND ioc.\"TYPE\" = 'CREDIT' ")
    @Results(value = {
        @Result(property = "bavicLabel", column = "BAVIC_LABEL"),
        @Result(property = "bavicRole", column = "ROLE")
    })
    Set<BavicCredit> selectCredits(@Param("informationObjetId") Long informationObjetId);
}

我的问题是此代码没有 return BavicCredit class 集。 Set 总是空的，就像第一个 class 中定义的那样。似乎根本没有调用方法 selectCredits。外键存在于数据库中。我相信，我遗漏了一些小代码或属性映射。

Java11,Springboot 2.5.0,Mybatis mybatis-spring-boot-starter 2.2.0,数据库Oraclecom.oracle.database.jdbcojdbc8

提前致谢。

PS 我已经尝试了 One to many relationship in MyBatis 但仍然缺少一些东西

Answer 1

当使用嵌套 select [1] 时，column 属性的值应该是第一个查询结果集中的列名。
在您的第一个查询的结果集中，嵌套查询的参数是 id，因此 @Result 应该如下所示。

@Result(
  property = "creditsList",
  column = "id",
  javaType = Set.class,
  many = @Many(select = "selectCredits"))

[1] 有关基础知识，请阅读此 section 文档。

Spring Boot + Java 11 + Mybatis: @Many 在注解方法中被忽略

Spring Boot + Java 11 + Mybatis: @Many is ignored in Annotations approach

java

oracle

mybatis

spring-boot