java list 分页,方便分批处理整个list的数据

java list 分页,方便分批处理整个list的数据
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

public class ListPageUtil<T> {
	
    /**
     * 每页显示条数
     */
    private int pageSize;
    
    /**
     * 总页数
     */
    private int pageCount;
    
    /**
     * 原集合
     */
    private List<T> data;

    public ListPageUtil(List<T> data, int pageSize) {
        if (data == null || data.isEmpty()) {
            throw new IllegalArgumentException("data must be not empty!");
        }

        this.data = data;
        this.pageSize = pageSize;
        this.pageCount = data.size()/pageSize;
        if(data.size()%pageSize!=0){
        	this.pageCount++;
        }
    }

    /**
     * 得到分页后的数据
     *
     * @param pageNum 页码
     * @return 分页后结果
     */
    public List<T> getPagedList(int pageNum) {
        int fromIndex = (pageNum - 1) * pageSize;
        if (fromIndex >= data.size()) {
            return Collections.emptyList();
        }

        int toIndex = pageNum * pageSize;
        if (toIndex >= data.size()) {
            toIndex = data.size();
        }
        return data.subList(fromIndex, toIndex);
    }

    public int getPageSize() {
        return pageSize;
    }

    public List<T> getData() {
        return data;
    }

    public int getPageCount() {
		return pageCount;
	}

	public static void main(String[] args) {
        Integer[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12};
        List<Integer> list = Arrays.asList(array);

        ListPageUtil<Integer> pager = new ListPageUtil<Integer>(list, 10);
       
        System.out.println(pager.getPageCount());

        List<Integer> page1 = pager.getPagedList(1);
        System.out.println(page1);

        List<Integer> page2 = pager.getPagedList(2);
        System.out.println(page2);

        List<Integer> page3 = pager.getPagedList(3);
        System.out.println(page3);
    }
}

代码技巧