Java List集合多种情况处理方法

1.List集合交集（所有属于集合list1且属于集合list2的元素所组成的集合）

List intersection = list1.stream().filter(item -> list2.contains(item)).collect(toList());
System.out.println("---交集 intersection---");
intersection.parallelStream().forEach(System.out :: println);

2.List集合差集 (两个集合扣除共同部分后剩余的部分组成的集合)

List reduce1 = list1.stream().filter(item -> !list2.contains(item)).collect(toList());
System.out.println("---差集 reduce1 (list1 - list2)---");
reduce1.parallelStream().forEach(System.out :: println);

3.List集合并集

List listAll = list1.parallelStream().collect(toList());
List listAll2 = list2.parallelStream().collect(toList());
listAll.addAll(listAll2);
System.out.println("---并集 listAll---");
listAll.parallelStream().forEachOrdered(System.out :: println);

4.List集合去重并集

List listAllDistinct = listAll.stream().distinct().collect(toList());
System.out.println("---得到去重并集 listAllDistinct---");
listAllDistinct.parallelStream().forEachOrdered(System.out :: println);

5.获取List集合某个字段生成新集合

List custIds = list.stream().map(p -> p.getCust_id()).collect(toList());

6.将List集合分批新增

List> partitionList = Lists.partition(levelInfoVoList, 1000);
for (List list : partitionList) {
	mtclubMemberLevelInfoDao.insertMemberLevelData(list);
}

7.List集合按照字段排序

list.sort((x, y) -> Double.compare(Double.valueOf(x.getPrice()), Double.valueOf(y.getPrice())));

8.抽取List集合的单个字段，并且去重

List storeNameList = groupTotalVoList_tmp.stream().map(p -> p.getStore_name()).distinct().collect(Collectors.toList());

9.Java中List转换为数组Array

ArrayList list=new ArrayList();
String[] array = new String[list.size()];
list.toArray(array);

10.Java中Array转换为数组List

String[] s = {"a","b","c"};
List list = java.util.Arrays.asList(s);(查询操作)
List list = new ArrayList<>(Arrays.asList(s))(可进行增加和删除操作)

11.标准json数据，将Object转换为List

List list = JSON.parseArray(JSON.toJSONString(objects), T.class);

12.List集合就某一个字段去重

List arrays = list.stream().collect(Collectors.collectingAndThen(Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(OutStockLogisticsVo::getLogistic_number))), ArrayList::new));

13.List集合的删除操作

Iterator iterator = list.iterator();
while (iterator.hasNext()) {
   iterator.remove();      
}

所谓的人生开挂，不过是厚积薄发！ 欢迎评论和转载！