Foreword
java8 the biggest bright spot is lambda, let us use the syntax C # linq habits, but also themselves. But compared to C # syntactic sugar is still far worse.
Difference, union, intersection
@Test public void test1(){ List<Integer> list1=new ArrayList<>(); list1.add(1); list1.add(2); list1.add(3); List<Integer> list2=new ArrayList<>(); list2.add(3); list2.add(4); list2.add(5); System.out.println("====求交集==="); List<Integer> list=list1.stream().filter(t->list2.contains(t)).collect(Collectors.toList()); list.stream().forEach(System.out::println); System.out.println("====求差集==="); list=list1.stream().filter(t-> !list2.contains(t)).collect(Collectors.toList()); list.stream().forEach(System.out::println); System.out.println("====求并集==="); list.addAll(list1); list.addAll(list2); list=list.stream().distinct().collect(Collectors.toList()); list.stream().forEach(System.out::println); }