Question

我正在将SQL视图映射到带有休眠@Subselect注释的实体类。基本上，它看起来像这样：

@Subselect(
    "SELECT table1.*, table2.id as tid FROM " 
   + "table1 INNER JOIN table2 on table2.field = table1.field"
)
@Entity
@Immutable
class Entity {
    // fields
}

加入后，我可能会收到类似以下的内容

========================================
| table1.id | table1.field | table2.id |
========================================
|         1 |            1 |         1 |
========================================
|         1 |            1 |         2 |
========================================

因此table2中的几条记录可以连接到table1中的一行。很好，但是在Java实体中，我想将其映射为一对多关系（一个实体映射到多个table2实体），这是我写的，适用于其他类型的关系：

@Subselect(
    "SELECT table1.*, table2.id as tid FROM " 
   + "table1 INNER JOIN table2 on table2.field = table1.field"
)
@Entity
@Immutable
class Entity {
    @OneToMany
    @JoinColumn(name = "tid", updatable = false, insertable = false)
    private Set<Table2Entity> elements = new HashSet<>();
}

但是，实体中的集合始终为空，为什么呢？上述方法适用于一对一和多对一关系。

Answer 1

转起来，不需要与sql联接即可为视图实体带来一对多的关系。我是这样解决的：

Invocation.Builder invocationBuilder3 = targetWithParams.request(new String[] { "application/hal+json" });
        invocationBuilder3.header("Authorization", "Bearer " + accessToken);
        invocationBuilder3.header("accept", "application/json");
        invocationBuilder3.header("content-type", "multipart/form-data");
        Form form = new Form().param("sip", "0801752b800ee8a6_864deeb87909431896d7a861eecdda98.zip")
                .param("format", "sip_zip");

        final FileDataBodyPart filePart = new FileDataBodyPart("sip", new File("0801752b800ee8a6_864deeb87909431896d7a861eecdda98.zip"));
        System.out.println("name:"+filePart.getName());
        FormDataMultiPart formDataMultiPart = new FormDataMultiPart();
        final FormDataMultiPart multipart = (FormDataMultiPart) formDataMultiPart.field("format", "sip_zip").bodyPart(filePart);

        Response response = invocationBuilder3.post(Entity.entity(multipart.toString().getBytes(), MediaType.MULTIPART_FORM_DATA_TYPE));

我只需要在需要连接的表上放置列名。

具有一对多关系的休眠地图视图

1 个答案: