java8 stream获取最大、最小值

  static List<User> list = new ArrayList<User>();

    static void init() {
        list.add(new User("1号", 1));
        list.add(new User("2号", 5));
        list.add(new User("3号", 7));

    }
       
    public static void main(String[] args) {
        init();   //orElse(); 给默认值,让代码更加友好                             
        int max = list.stream().mapToInt(value -> value.age).max().orElse(0);
        int min = list.stream().mapToInt(value -> value.age).min().orElse(0);
        int sum = list.stream().mapToInt(value -> value.age).sum();
        double average = list.stream().mapToInt(value -> value.age).average().getAsDouble();
        System.out.println("最大值：" + max + "最小值：" + min + "平均值" + average + "总值" + sum);