springboot jpa---->总结一下遇到的问题

Native Query throw exception

dto code

import lombok.Value;

@Value

public class IdsOnly {

    Integer id;

    String otherId;

}

repository

public interface TestTableRepository extends JpaRepository<TestTable, Integer> {

    @Query(value = "select id, otherId from TestTable where CreationDate > ?1", nativeQuery = true)

    public Collection<IdsOnly> findEntriesAfterDate(Date creationDate);

}

service

List<IdsOnly> results = ttRepo.findEntriesAfterDate(theDate);

exception

org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type [org.springframework.data.jpa.repository.query.AbstractJpaQuery$TupleConverter$TupleBackedMap] to type [com.example.IdsOnly]

解决方法有两种

使用NativeQuery：将IdsOnly更换成接口，提供属性的get方法。

public interface IdsOnly {

    Integer getId();

    String getOtherId();

}

不使用NativeQuery

@Query("select new com.example.IdsOnly(t.id, t.otherId) from TestTable t where t.creationDate > ?1")

Jpa中没有update方法

jpa中只有save方法，如果你传递的对象的主键在数据库中存在，那么就是更新操作。否则就是插入操作。

Delete operation

JpaRepository Not supported for DML operations [delete query]

Repository: add @Modifying

@Modifying

void deleteByUserIdAndToolId(Integer userId, Integer toolId);

Service: add @Transactional

@Transactional

public void doDeleteUserTool(Integer userId, Integer toolId) {

    userToolMapper.deleteByUserIdAndToolId(userId, toolId);

}

To be continue

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