java中两个list集合取并集、交集和差集&对list数据进行筛选

java中两个list集合取并集、交集和差集

List<String> list1 = new ArrayList<>();
List<String> list2 = new ArrayList<>();
list1.add("A");
list1.add("C");
list1.add("D");
list2.add("A");
list2.add("B");
 
 
//获取两个集合并集
List<String> strings = new ArrayList<>(CollectionUtils.union(list1, list2));
System.out.println(strings);
//[A, B, C, D]
 
//获取两个集合交集
List<String> strings1 = new ArrayList<>(CollectionUtils.intersection(list1, list2));
System.out.println(strings1);
//[A]
 
//获取两个集合交集的补集
List<String> strings12 = new ArrayList<>(CollectionUtils.subtract(list1, list2));
System.out.println(strings12);
//[C, D]
 
//获取两个集合差集的补集
List<String> strings2 = new ArrayList<>(CollectionUtils.disjunction(list1, list2));
System.out.println(strings2);
//[B, C, D]

对list数据进行筛选

//对相同内容的list进行去重
List<AppleNode> disList = appleList.stream().distinct().collect(Collectors.toList());
 
 
//取出name和code和apleNewList中的数据一致的内容
List<Apple> filterAppleList = appleNewList.stream().filter(apple-> name.equals(apple.getName()).
                                                    filter(apple -> code.equals(apple.getCode())).collect(Collectors.toList());
 
//根据list中的内容取出最大值对应的实体
Apple filterHs = filterHistoryList.stream().max(Comparator.comparing(Apple:getNumbet).get();