x
60
60
1
import java.util.ArrayList;2
import java.util.List;3
4
public class IntStreamTest1 {5
6
public static void main(String[] args) {7
8
List<Person> people = new ArrayList<>();9
people.add(new Person("Alice", 30));10
people.add(new Person("Bob", 19));11
people.add(new Person("Ronald", 40));12
people.add(new Person("Jimi", 27));13
people.add(new Person("Suzan", 60));14
people.add(new Person("Jeff", 80));15
people.add(new Person("Maria", 52));16
17
// min18
int min = people.stream().mapToInt(p -> p.getAge()).min().orElse(0);19
System.out.println(min);20
// 1921
22
// max23
int max = people.stream().mapToInt(p -> p.getAge()).max().orElse(0);24
System.out.println(max);25
// 8026
27
// sum28
int sum = people.stream().mapToInt(p -> p.getAge()).sum();29
System.out.println(sum);30
// 30831
32
// average33
double ave = people.stream().mapToInt(p -> p.getAge()).average().orElse(0.0);34
System.out.println(ave);35
// 44.036
}37
}38
39
class Person {40
41
private String name;42
private Integer age;43
44
public Person(String name, Integer age) {45
this.name = name;46
this.age = age;47
}48
49
public Integer getAge() {50
return age;51
}52
53
public String getName() {54
return name;55
}56
57
public String toString() {58
return "name:" + name + " age:" + age;59
}60
}