java - Convert Page<Entity> to PageDTO<EntityDTO> -

i using spring data jpa.

my controller looks following

    @requestmapping(value = "/pages/{pagenumber}", method = requestmethod.get, consumes = mediatype.application_json_value, produces = mediatype.application_json_value)     public responseentity<page<user>> paginateduser(@pathvariable final integer pagenumber)     {         final pagerequest request = new pagerequest(pagenumber - 1, default_page_size, sort.direction.desc, "starttime");         return new responseentity<>(userrepository.findall(request), httpstatus.ok);     } 

now decided send instead of page object, pagedto object restrict things sending.is there way can convert page pagedto using java 8.

i saw page derived iterable guess can following not sure how put pagedto , userdto.

streamsupport.stream(userrepository.findall(request).spliterator(),false) 

is there effecient java 8 way this.

i came solution

     @requestmapping(value = "/pages/{pagenumber}", method = requestmethod.get, consumes = mediatype.application_json_value, produces = mediatype.application_json_value)      public responseentity<pagedto> paginateduser(@pathvariable final integer pagenumber)         {             final pagerequest request = new pagerequest(pagenumber - 1, default_page_size, sort.direction.desc, "starttime");             final page<user> page = userrepository.findall(request);             return new responseentity<>(new pagedto(page, streamsupport.stream(page.getcontent().spliterator(), true).map(userdto::new)                     .collect(collectors.tolist())), httpstatus.ok);         }   public class pagedto {      private int beginindex;      private int currentindex;      private int endindex;      private list<?> entities;      public pagedto(final page<?> page, final list<?> entities) {         this.entities = entities;         this.currentindex = page.getnumber() + 1;         this.beginindex = math.max(1, currentindex - 5);         this.endindex = math.min(beginindex + 10, page.gettotalpages());     } 

would know if there effecient way this?

i know old question, ran same problem , i'd provide possible solution whomever may interested. here found helped me code: https://github.com/pkainulainen/spring-data-jpa-examples/blob/master/query-methods/src/main/java/net/petrikainulainen/springdata/jpa/todo/todomapper.java

i used jparepository paginates data, dto page have same parameters (page number, size etc). here repository:

@repository public interface repository extends jparepository<entity, integer> {      /**      * name method according query need execute      * e.g. findall --> return rows satisfy following conditions,      * byusername --> username field in entity class,      * @param pageable: pagination applied on data.      * @return       */     public page<entity> findallbyusername(string username, pageable pageable);  } 

this method mapping:

public page<entitydto> findbyusername(string username, pageable pageable){     page<entity> entitypage = entityrepository.findallbyusername(username, pageable);     list<entitydto> dtos = mapper.entitytoentitydtos(entitypage.getcontent());     return new pageimpl<>(dtos, pageable, entitypage.gettotalelements()); } 

and mapstruct mapper:

import org.mapstruct.factory.mappers;  /**  * mapper converting entity dto.  */ @mapper(componentmodel = "spring", uses = {}) public interface mapper {      /**      * interface declares member instance, providing clients access mapper implementation,      * file target\generated-sources\com\company\springapp\dto\mappers\mapperimpl.java      * (automatically generated when compiling project).      */     auditmapper instance = mappers.getmapper( mapper.class );      /**      * convert entity dto.      * mappings used 'bind' entity fields dto fields (for mapper's implementation).      * @param entity      * @return       */     @mappings({         @mapping(source = "id", target = "id"),         @mapping(source = "username", target = "dtousername"),         @mapping(source = "action", target = "dtoaction")     })     public entitydto entitytoentitydto(entity entity);      /**      * convert entities' list dtos' list.      * @param entities      * @return       */     public list<entitydto> entitiestoentitydtos(list<entity> entities);  }