Native List在Jpa / hibernate + Spring中插入查询

Question

I want to insert a list of Objects in my db. In a special case I know that they primary key (not auto-generated) is not already there. Since I need to insert a big collection, the save(Iterable<Obj> objects) is to slow.

Therefore I consider using a native query. native insert query in hibernate + spring data

In the previous answer, it does not say how to insert a collection of objects. Is this possible?

@Query("insert into my_table (date, feature1, feature2, quantity) VALUES <I do not know what to add here>", nativeQuery = true)
void insert(List<Obj> objs);

Of course if you have a better solution overall, Its even better.

Answer 1

I ended up implementing my own repository. The performance of this is really good, 2s instead of 35s before to insert 50000 elements. The problem with this code is that it does not prevent sql injections.

I also tryed to build a query using setParameter(1, ...) but somehow JPA takes a long time to do that.

class ObjectRepositoryImpl implements DemandGroupSalesOfDayCustomRepository {

    private static final int INSERT_BATCH_SIZE = 50000;

    @Autowired
    private EntityManager entityManager;

    @Override
    public void blindInsert(List<SomeObject> objects) {
         partition(objects, INSERT_BATCH_SIZE).forEach(this::insertAll);
    }

    private void insertAll(List<SomeObject> objects) {
         String values = objects.stream().map(this::renderSqlForObj).collect(joining(","));
         String insertSQL = "INSERT INTO mytable (date, feature1, feature2, quantity) VALUES ";
         entityManager.createNativeQuery(insertSQL + values).executeUpdate();
         entityManager.flush();
         entityManager.clear();
    }

    private String renderSqlForObj(Object obj) {
        return "('" + obj.getDate() + "','" +
            obj.getFeature1() + "','" +
            obj.getFeature2() + "'," +
            obj.getQuantity() + ")";
    }
}