Java Stream - 如何从收集器创建IntSummaryStatistics

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import java.util.Arrays;
import java.util.IntSummaryStatistics;
import java.util.List;
import java.util.stream.Collectors;
public class Main {
  public static void main(String[] args) throws Exception {
    List<Person> persons =
        Arrays.asList(
            new Person("Max", 18),
            new Person("Peter", 23),
            new Person("Pamela", 23),
            new Person("David", 12));   
    
    IntSummaryStatistics ageSummary =
        persons
            .stream()
            .collect(Collectors.summarizingInt(p -> p.age));
    System.out.println(ageSummary);
  }
}
class Person {
  String name;
  int age;
  Person(String name, int age) {
      this.name = name;
      this.age = age;
  }
 
 
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