public class Java8Test {
public
static
void
main(String[] args) {
Person p1 =
new
Person(
"麻子"
,
31
);
Person p2 =
new
Person(
"李四"
,
20
);
Person p3 =
new
Person(
"王五"
,
26
);
List<Person> personList =
new
ArrayList<Person>();
personList.add(p1);
personList.add(p2);
personList.add(p3);
//java8遍歷
personList.forEach(p -> System.out.println(p.getAge()));
//按照person的 age進行排序
//方法一
personList.sort((o1, o2) -> o1.getAge().compareTo(o2.getAge()));
//正序
personList.sort((o1, o2) -> o2.getAge().compareTo(o1.getAge()));
//倒序
//方法二
personList.sort(Comparator.comparing(Person::getAge));
// 正序
personList.sort(Comparator.comparing(Person::getAge).reversed());
// 倒序
//遍歷
personList.forEach(p -> System.out.println(p.getAge()));
System.out.println(
"========================================"
);
//獲取年齡最大的Person
Person maxAgePerson = personList.stream().max(Comparator.comparing(Person::getAge)).get();
System.out.println(maxAgePerson.getAge());
System.out.println(
"========================================"
);
//獲取年齡最小的Person
Person minAgePerson = personList.stream().min(Comparator.comparing(Person::getAge)).get();
System.out.println(minAgePerson.getAge());
//過濾出年齡是20的person，想過濾出什么條件的都可以
List<Person> personList1 = personList.stream().filter(person -> person.getAge() ==
20
).collect(Collectors.toList());
//統計出年齡等於20的個數
long
count = personList.stream().filter(person -> person.getAge() ==
20
).count();
//獲得年齡的平均值
double
asDouble = personList.stream().mapToInt(person -> person.getAge()).average().getAsDouble();
//獲得年齡的求和
int
sum = personList.stream().mapToInt(person -> person.getAge()).sum();
}
}