java 内存分页 java8

java8 内存分页工具 （记录一下）

package com.barton;

import java.util.ArrayList;
import java.util.List;
import java.util.function.Consumer;

/**
 * create by barton on 2020-6-30
 */
public class MemPageHelper {
    public static  void pageHelper(Integer pageSize,
                                      List list,
                                      Consumer> consumer){
        //默认 100 分页
        if(pageSize == null || pageSize == 0){
            pageSize = 100;
        }
        Integer totalSize = list.size();
        Integer totalPage = totalSize / pageSize;
        if (totalSize % pageSize != 0) {
            totalPage += 1;
            if (totalSize < pageSize) {
                pageSize = totalSize;
            }
        }
        
        for (int pageNum = 1; pageNum < totalPage + 1; pageNum++) {
            int starNum = (pageNum - 1) * pageSize;
            int endNum = pageNum * pageSize > totalSize ? (totalSize) : pageNum * pageSize;
            consumer.accept(list.subList(starNum,endNum));
        }

    }
    public static void main(String[] args) {
        List list = new ArrayList<>();
        for(int i=0;i<100;i++){
            list.add(i);
        }

        pageHelper(25,list, pageList->{
            System.out.println(pageList);
            }

        );
    }
}