Category checking to particular DLFile in liferay

This blog will help you to check the particular categorie assigned to DLFile or not, and also helps to fectch all the categories from database,

import com.liferay.portlet.asset.model.AssetCategory;
import com.liferay.portal.kernel.dao.orm.DynamicQuery;
import com.liferay.portal.kernel.dao.orm.DynamicQueryFactoryUtil;
import com.liferay.portal.kernel.dao.orm.PropertyFactoryUtil;

 List categoryList = null;
//Using dynamic query to fetch all the categories with the name "IMTHIYAZ"
DynamicQuery query = DynamicQueryFactoryUtil.forClass(AssetCategory.class).add(PropertyFactoryUtil.forName("name").eq("IMTHIYAZ"));
               categoryList = AssetCategoryLocalServiceUtil.dynamicQuery(query, 0,1);
//Result list contains all the list of AssetCategory Objects with the Name "IMTHIYAZ"

import com.liferay.portlet.documentlibrary.model.DLFileEntry;
import com.liferay.portlet.asset.model.AssetEntry;

AssetEntry assetentry = null;
DLFileEntry fileEntryObj ; Assuming this object conatins file
//getting assetentry of particular file
 assetentry = AssetEntryLocalServiceUtil.getEntry( DLFileEntry.class.getName(), fileEntryObj.getPrimaryKey());
//fetching all categories of particular assetentry
long assetCategoryId[] = assetentry.getCategoryIds();
List assetCategories = assetentry.getCategories();
 if(assetCategories.contains(categoryList.get(0))){
//This file contains IMTHIYAZ category
}