Java新特性解读JDK8之收集器summarizing集合统计

package com.example.streamdemo;


import java.util.Arrays;
import java.util.IntSummaryStatistics;
import java.util.List;
import java.util.stream.Collectors;


public class SummarizingDemo {


  public static void main(String[] args) {
    List<Boss> asList = Arrays.asList(new Boss(20, "jack"), new Boss(20, "tony"), new Boss(22, "jerry"),
        new Boss(22, "marry"), new Boss(25, "jony"), new Boss(25, "bob"), new Boss(27, "james"));
    IntSummaryStatistics intSummaryStatistics = asList.stream().collect(Collectors.summarizingInt(Boss::getAge));
    System.out.println("平均值: " + intSummaryStatistics.getAverage());
    System.out.println("统计个数: " + intSummaryStatistics.getCount());
    System.out.println("最大值: " + intSummaryStatistics.getMax());
    System.out.println("最小值: " + intSummaryStatistics.getMin());
    System.out.println("总和: " + intSummaryStatistics.getSum());
  }
}


class Boss {


  private int age;
  private String name;


  public Boss() {
    super();
  }


  public Boss(int age, String name) {
    super();
    this.age = age;
    this.name = name;
  }


  public int getAge() {
    return age;
  }


  public void setAge(int age) {
    this.age = age;
  }


  public String getName() {
    return name;
  }


  public void setName(String name) {
    this.name = name;
  }


}