Java集合分页工具类

此工具类支持List、Set集合分页

如有疑问，欢迎留言！

package xxx;

import com.google.common.collect.Lists;
import com.google.common.collect.Sets;
import org.apache.commons.collections.CollectionUtils;

import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
import java.util.Set;

import static java.util.stream.Collectors.toList;
import static java.util.stream.Collectors.toSet;


public class CollectionUtil {

    
    public static  List subList(Integer pageNumber, Integer pageSize, List list){
        if(CollectionUtils.isEmpty(list)) return Lists.newArrayList();
        int page = (pageNumber - 1) * pageSize;
        List nowCollect = list.stream().skip(page).limit(pageSize).collect(toList());
        return Optional.ofNullable(nowCollect).orElse(Lists.newArrayList());
    }

    
    public static  Set subSet(Integer pageNumber, Integer pageSize, Set set){
        if(CollectionUtils.isEmpty(set)) return Sets.newHashSet();
        int page = (pageNumber - 1) * pageSize;
        Set nowCollect = set.stream().skip(page).limit(pageSize).collect(toSet());
        return Optional.ofNullable(nowCollect).orElse(Sets.newHashSet());
    }

    
    public static  List subSetToList(Integer pageNumber, Integer pageSize, Set set){
        if(CollectionUtils.isEmpty(set)) return Lists.newArrayList();
        List list = new ArrayList<>(set);
        return subList(pageNumber, pageSize, list);
    }

}