这里记录一下，虽然这个名字叫JAVA8新方法，但实际上JAVA8一点都不新，主要是我们的老removeIf方法Listlist1=Arrays.asList("one","two","three","four","five","six","seven");Listlist2=newArrayList<>(list1);//删除booleanresult=list2.removeIf(s->s.length()>4);System.out.println(结果);System.out.println(list2.stream().collect(Collectors.joining(",")));//输出trueone,two,four,five,six//替换list2.replaceAll(s->s.toUpperCase());System.out.println(list2.stream().collect(Collectors.joining(",")));//输出ONE,TWO,FOUR,FIVE,SIX//排序list2.sort(Comparator.naturalOrder());System.out.println(list2.stream().collect(Collectors.joining(",")));//输出五、四、一、六、二比较Comparatorcomparator=Comparator.comparing(Person::getName).thenComparing(Person::getAge);//反向比较ComparatorcomparatorReversed=comparator.reversed();//默认字母顺序Comparatorcomparator1=Comparator.naturalOrder();//先按空，然后按字母顺序排序Comparatorcomparator2=Comparator.nullsFirst(Comparator.naturalOrder());//按照字母顺序在前，最后为空Comparatorcomparator3=Comparator.nullsLast(Comparator.naturalOrder());//比较Longmax=Long.max(1L,2L);BinaryOperatorsum=(s1,s2)->s1+s2;sum=Long::sum;hashCodeLongl=2234324234234324L;inthash=l.hashCode();System.out.println(hash);hash=Long.hashCode(l);System.out.println(hash);//输出642554319642554319MapforEach,getOrDefault,putIfAbsentMapmap=newHashMap<>();map.put("key","value");map.forEach((key,value)->System.out.println(key+""+value));//输出键值//getOrDefaultPersondeafulPerson=newPerson();deafulPerson.setName("Test");Personp=(Person)map.getOrDefault("p",deafulPerson);System.out.println(p.getName());//输出TestPersonp1=newPerson();p1.setName("Test11");//putIfAbsentmap.putIfAbsent("p",p);System.out.println("putIfAbsent="+map.get("p"));//将key的值替换为p作为p1map.replace("p",p1);系统输出。println("replace=="+map.get("p"));//将键值p替换为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"));//输出putIfAbsent==Person{name='Test',age=0}replace==Person{name='Test11',age=0}replaceNew==Person{name='Test',age=0}replaceAll==Person{name='Test11',age=0}
