对list 分段截取方法是一个常见的操作，通常用于对list数据批量操作，常见的场景有返回分页展示数据，对大数据进行分批次插入数据库等

package com.hmdp.dto;import org.apache.commons.collections4.ListUtils;
import org.springframework.util.StringUtils;import java.text.ParseException;
import java.util.Arrays;
import java.util.List;/*** @Author: ldj* @Date: 2023/06/19/16:34* @Description: 对list分段截取*/
public class Tr {public static void main(String[] args) throws ParseException {List<String> list = Arrays.asList("a", "b", "c", "d", "e", "f", "g", "h", "i");Tr.subList1(list);Tr.subList2(list);Tr.subList3(list);Tr.subList4(list); //推荐System.out.println(Math.min(3, 2));}public static void subList1(List<String> list) {long beginTime = System.currentTimeMillis();if (StringUtils.isEmpty(list)) {return;}int beginIndex = 0;int subSize = 2;List<String> arrayList = null;while (beginIndex < list.size()) {if (beginIndex + subSize < list.size()) {arrayList = list.subList(beginIndex, beginIndex + subSize);} else {arrayList = list.subList(beginIndex, list.size());}beginIndex += subSize;System.out.println(arrayList);}long endTime = System.currentTimeMillis();System.out.println("subList1 cost time:" + (endTime - beginTime));}//方法2快一丢丢public static void subList2(List<String> list) {long beginTime = System.currentTimeMillis();if (StringUtils.isEmpty(list)) {return;}int beginIndex = 0;int subSize = 2;List<String> arrayList = null;if (list.size() % subSize == 0) {int size = list.size() / subSize;for (int i = 0; i < size; i++) {arrayList = list.subList(beginIndex, beginIndex + subSize);beginIndex = beginIndex + subSize;System.out.println(arrayList);}}if (list.size() % subSize > 0) {int size = list.size() / subSize;for (int i = 0; i < size; i++) {arrayList = list.subList(beginIndex, beginIndex + subSize);beginIndex = beginIndex + subSize;System.out.println(arrayList);}arrayList = list.subList(beginIndex, list.size());System.out.println(arrayList);}long endTime = System.currentTimeMillis();System.out.println("subList2 cost time:" + (endTime - beginTime));}/*** <dependency>* <groupId>org.apache.commons</groupId>* <artifactId>commons-collections4</artifactId>* <version>4.4</version>* </dependency>*/public static void subList3(List<String> list) {long beginTime = System.currentTimeMillis();List<List<String>> partitions = ListUtils.partition(list, 2);partitions.forEach(partition -> {System.out.println(partition);});long endTime = System.currentTimeMillis();System.out.println("subList3 cost time:" + (endTime - beginTime));}public static void subList4(List<String> list) {long beginTime = System.currentTimeMillis();List<String> arrayList = null;int subSize = 2;for (int beginIndex = 0; beginIndex < list.size(); beginIndex += subSize) {int endIndex = Math.min(beginIndex + subSize, list.size());arrayList = list.subList(beginIndex, endIndex);System.out.println(arrayList);}long endTime = System.currentTimeMillis();System.out.println("subList4 cost time:" + (endTime - beginTime));}}