Java8 使用 stream().map().collect提取对象的某一列值

        List list = new ArrayList<>();
        Person p1 = new Person("张三", 20, "江西");
        Person p2 = new Person("李四", 22, "北京");
        Person p3 = new Person("赵六", 26, "广东");
        list.add(p1);
        list.add(p2);
        list.add(p3);

        String str = list.stream().map(Person::getName).collect(Collectors.joining(","));
        System.out.println(str);//张三,李四,赵六

        //转list集合
        List list2 = list.stream().map(Person::getName).collect(Collectors.toList());

        
        list2.forEach(s -> System.out.println(s.toString()));

        //2、条件遍历
        list2.forEach(c->{
            if(c.equals("张三")){
                System.out.println(c);
            }
        });

       //set集合
        Set set = list.stream().map(Person::getName).collect(Collectors.toCollection(TreeSet::new));