Java8 Stream分割list集合

谁借莪１个温暖的怀抱￠ 2023-07-11 08:53 23阅读 0赞

使用Java8 Stream分割list集合，写好的工具类，可以直接用

package com.example.java8;
    
    import com.example.excel.Student;
    import org.apache.commons.collections4.CollectionUtils;
    
    import java.util.ArrayList;
    import java.util.Collections;
    import java.util.List;
    import java.util.stream.Collectors;
    import java.util.stream.Stream;
    
    public class StreamUtil { 
    
        /** * Description: Java8 Stream分割list集合 * @param list 集合数据 * @param splitSize 几个分割一组 * @return 集合分割后的集合 */
        public static <T> List<List<T>> splitList(List<T> list, int splitSize) { 
            //判断集合是否为空
            if (CollectionUtils.isEmpty(list))
                return Collections.emptyList();
            //计算分割后的大小
            int maxSize = (list.size() + splitSize - 1) / splitSize;
            //开始分割
            return Stream.iterate(0, n -> n + 1)
                    .limit(maxSize)
                    .parallel()
                    .map(a -> list.parallelStream().skip(a * splitSize).limit(splitSize).collect(Collectors.toList()))
                    .filter(b -> !b.isEmpty())
                    .collect(Collectors.toList());
        }
    
        public static void main(String[] args) { 
    
            List<Integer> list = new ArrayList<>(1001);
            for (int i = 0; i < 900; i++) { 
                list.add(i);
            }
            int splitSize = 100;
    
            List<List<Integer>> splitList = splitList(list, splitSize);
            for (List<Integer> integers : splitList) { 
                integers.forEach(System.out::println);
            }
    
    
            List<Student> list1 = new ArrayList<>();
            for (int i = 0; i < 10; i++) { 
                list1.add(new Student(111, "张三asdf", "男"));
                list1.add(new Student(111, "李四asd", "男"));
                list1.add(new Student(111, "王五", "女"));
            }
    
            List<List<Student>> splitList1 = splitList(list1, splitSize);
            for (List<Student> students : splitList1) { 
                students.forEach(e -> System.out.println(e.toString()));
            }
        }
    }