就记录在这吧，尽管这个名字叫JAVA8新办法，然而实际上JAVA8一点也不新啦，次要是咱们老了
list的removeIf办法

List<String> list1 = Arrays.asList("one","two","three","four","five","six","seven");List<String> list2 = new ArrayList<>(list1);//删除boolean result = list2.removeIf(s -> s.length() > 4);System.out.println(result);System.out.println(list2.stream().collect(Collectors.joining(",")));//输入trueone,two,four,five,six//替换list2.replaceAll(s->s.toUpperCase());System.out.println(list2.stream().collect(Collectors.joining(",")));//输入ONE,TWO,FOUR,FIVE,SIX//排序list2.sort(Comparator.naturalOrder());System.out.println(list2.stream().collect(Collectors.joining(",")));//输入FIVE,FOUR,ONE,SIX,TWO

比拟

Comparator<Person> comparator = Comparator.comparing(Person::getName).thenComparing(Person::getAge);//反向比拟Comparator<Person> comparatorReversed = comparator.reversed();//默认字母程序Comparator<String> comparator1 = Comparator.naturalOrder();//先按空后再依照字母程序Comparator<String> comparator2 = Comparator.nullsFirst(Comparator.naturalOrder());//先依照字母程序，最初排空Comparator<String> comparator3 = Comparator.nullsLast(Comparator.naturalOrder());//比拟Long max = Long.max(1L,2L);BinaryOperator<Long> sum = (s1,s2) -> s1 + s2;sum = Long::sum;

hashCode

Long l = 2234324234234324L;int hash = l.hashCode();System.out.println(hash);hash = Long.hashCode(l);System.out.println(hash);//输入642554319642554319

Map forEach，getOrDefault,putIfAbsent

Map<String,Object> map =new HashMap<>();map.put("key","value");map.forEach((key,value)-> System.out.println(key+" "+value));//输入key value//getOrDefaultPerson deafulPerson = new Person();deafulPerson.setName("Test");Person p = (Person) map.getOrDefault("p",deafulPerson);System.out.println(p.getName());//输入TestPerson p1 = new Person();p1.setName("Test11");//putIfAbsentmap.putIfAbsent("p", p);System.out.println("putIfAbsent=="+map.get("p"));//替换key为p的值为p1map.replace("p", p1);System.out.println("replace=="+map.get("p"));//替换key值为p的为defaultPeronmap.replace("p", p1,deafulPerson);System.out.println("replaceNew=="+map.get("p"));//lambda替换map.replaceAll((key,oldPerson) -> p1);System.out.println("replaceAll=="+map.get("p"));//输入putIfAbsent==Person{name='Test', age=0}replace==Person{name='Test11', age=0}replaceNew==Person{name='Test', age=0}replaceAll==Person{name='Test11', age=0}