java - NativeQuery Spring Data 返回对象

Question

我需要像这样在 Spring Data 中实现一个查询:-

Select User.name, sum(Activity.minutes) 
From User, Activity, ActivityStatus
Where User.id = ActivityStatus.userId
And Activity.id = ActivityStatus.activityId
AND ActivityStatus = "COMPLETED"
GROUP BY user.name;

所以我需要加入 3 个表，因此我必须使用 @Query 和 nativeQuery = true(如果我在这里错了请纠正我)

所以我的 Repository 方法看起来像这样:-

@Query(value = "Select User.name, sum(Activity.minutes) as total_minutes
    From User, Activity, ActivityStatus
    Where User.id = ActivityStatus.userId
    And Activity.id = ActivityStatus.activityId
    AND ActivityStatus = "COMPLETED"
    AND User.Type = ?1
    GROUP BY user.name;",
    nativeQuery = true
    )
List<MyObj> getTotalActivityMinutesByUserType(String userType);

MyObj 类如下所示:-

public class MyObj {
    String name;
    long total_minutes;

// getter and setter methods

    public MyObj(String name, long total_minutes) {
        this.name = name;
        this.total_minutes = total_minutes;
    }
}

我的测试方法:-

@Test
public void TotalActivityTest() throws Exception {
    List<MyObj> objA = myRepository.getTotalActivityMinutesByUser("TEST");

}

我得到以下异常:-

org.springframework.core.convert.ConversionFailedException: Failed to convert from type [java.lang.Object[]] to type [com.mycomp.MyObj] for value '{TEST, 5.0}'; nested exception is org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type [java.lang.String] to type [com.mycomp.dto.MyObj]

我需要一种方法将结果作为 MyObj 返回。 (或者至少是一种将其转换为 MyObj 的方法)这可能吗？

编辑:

根据@Cepr0 的回答构建我的实体类如下所示:-

@Entity
public class ActivityStatus extends Base {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @ManyToOne(cascade = {CascadeType.PERSIST, CascadeType.MERGE, CascadeType.REFRESH, CascadeType.DETACH})
    private Activity activity;

    @ManyToOne(cascade = {CascadeType.PERSIST, CascadeType.MERGE, CascadeType.REFRESH, CascadeType.DETACH})
    private User user;

}

我不确定 JPQL 中的 JOIN 查询应该是什么样子...

Answer 1

只需使用 Projection和 JPQL查询:

public interface NameAndDuration {
    String getName();
    Long getDuaration();
}

@Query("select u.name as name, sum(a.minutes) as duration from User u join u.activityStatus st join st.activity a where st.status = "COMPLETED" and u.type = ?1 group by u.name")
List<NameAndDuration> getNameAndDurationByUserType(String userType);

List<NameAndDuration> list = getNameAndDurationByUserType("TEST");
String userName = list.get(0).getName();

此查询可能不完全符合您的需要，因为我不知道您的实体类的结构。但是如果你给他们看我会更正查询...