Person p1 = new Person();

        p1.setName("P1");

        p1.setAge(10);

        Person p2 = new Person();

        p2.setName("pp2");

        p2.setAge(9);

        Person p3 = new Person();

        p3.setName("p3");

        p3.setAge(5);

        List<Person> list = new ArrayList<>();

        list.add(p1);

        list.add(p2);
//若最后不添加collect方法，则返回类型是stream

        list = list.stream().filter(person ->   person.getAge()>5).collect(Collectors.toList());

        System.out.println(list);

输出结果：

[Person{name='P1', age=10}, Person{name='pp2', age=9}]

List<String> list = Stream.of("a","b","wo").map(string -> string.toUpperCase()).collect(Collectors.toList());

System.out.print(list);

输出结果：

[A, B, WO]

List<Integer> list = Stream.of("1","2").mapToInt(e ->Integer.parseInt(e)).boxed().collect(Collectors.toList());

//maptoInt之后是IntStream类型，需要用boxed转换为Stream