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遍历
personList.forEach(p -> System.out.println(p.getAge()));
//按照person的 age进行排序
//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
//遍历
personList.forEach(p -> System.out.println(p.getAge()));
System.out.println( "========================================" );
//获取年龄最大的Person
Person maxAgePerson = personList.stream().max(Comparator.comparing(Person::getAge)).get();
System.out.println(maxAgePerson.getAge());
System.out.println( "========================================" );
//获取年龄最小的Person
Person minAgePerson = personList.stream().min(Comparator.comparing(Person::getAge)).get();
System.out.println(minAgePerson.getAge());
//过滤出年龄是20的person，想过滤出什么条件的都可以
List<Person> personList1 = personList.stream().filter(person -> person.getAge() == 20 ).collect(Collectors.toList());
//统计出年龄等于20的个数
long count = personList.stream().filter(person -> person.getAge() == 20 ).count();
//获得年龄的平均值
double asDouble = personList.stream().mapToInt(person -> person.getAge()).average().getAsDouble();
//获得年龄的求和
int sum = personList.stream().mapToInt(person -> person.getAge()).sum();
}
}