使用ProjectionFactoryUtil时出现Liferay异常

Question

Am using ProjectionFactoryUtil to get specific columns eg : i want to gett ID and Name from table DETAIL_TABLE

am using Dynamic query

DynamicQuery dynQuery = DynamicQueryFactoryUtil.forClass(DetailTable.class);

ProjectionList projectionList = ProjectionFactoryUtil.projectionList();

projectionList.add(ProjectionFactoryUtil.property("ID"));
projectionList.add(ProjectionFactoryUtil.property("NAME"));

dynQuery.setProjection(projectionList);

after that am retriving the query using

List<DetailTable> detailList = DetailTableLocalServiceUtil.dynamicQuery(dynQuery);

but when am trying to iterate it am getting class cast exception at the following line

for(DetailTable dt : detailList){
}

the exception is " Ljava.lang.Object; cannot be cast to com.detail.model.DetailTable "

the Service util class returns the same DetailTable List ,i don't know why its giving me the class cast exception

The exception is not coming when am not using the Projections

Answer 1

When you add projections in DynamicQuery , it returns you list of array of Object type.

Here you are trying to cast that result with List<DetailTable> , thats why its throwing exception.

Instead use List<Object[]> and then cast array items according to its type(db type).