/**
     * 获取年龄是22岁的员工
     */
    @Test
    public void testFilter() {
       list.stream()
               .filter(employee -> employee.getAge() == 22)
               .forEach(System.out::println);
    }

    /**
     *  获取所有员工的姓名，并用"，"连接
     */
    @Test
    public void testMap() {
        String str = list.stream()
                .map(Employee::getName)
                .collect(Collectors.joining(","));
        System.out.println(str);
    }

    /**
     * 按照工资倒序排列，并获取第一个
     */
    @Test
    public void testSort() {
        Optional<Employee> optional = list.stream().sorted((e1, e2) -> {
            if (e1.getSlary() > e2.getSlary()) {
                return -1;
            } else if (e1.getSlary() == e2.getSlary()) {
                return 0;
            } else {
                return 1;
            }
        }).findFirst();

        System.out.println(optional.get());
    }

    /**
     * 最少工资
     */
    @Test
    public void testMin() {
        Double slary = list.stream()
                .map(Employee::getSlary)
                .min(Double::compareTo)
                .get();

        System.out.println(slary);
    }

    /**
     * 根据年龄进行分组
     */
    @Test
    public void testGroup() {
        Map<Integer, List<Employee>> map = list.stream().collect(Collectors.groupingBy(Employee::getAge));
        System.out.println(map);
    }

    /**
     * 工资大于5000的个数
     */
    @Test
    public void testCount() {
        Long count = list.stream().filter(employee -> employee.getSlary() > 8000)
                .count();

        System.out.println(count);
    }

    @Test
    public void testA() {

        BiPredicate<String, String> predicate2 = (s1, s2) -> s1.equals(s2);

        BiPredicate<String, String> predicate = String::equals;
        BiConsumer<List, String> bf = List::add;
        Function<Employee, String> f = Employee::getName;
        Supplier<String> s = String::new;

    }

    /**
     * 总薪水
     */
    @Test
    public void testStatistic() {
        DoubleSummaryStatistics statistics = list.stream().collect(Collectors.summarizingDouble(Employee::getSlary));
        System.out.println(statistics.getSum());
    }