strm().filter().collect()和stream().map().collect()的作用

public class People { 
   
    private Integer id;
    private String name;
    private Boolean sex;
//省略
}

public class Filter { 

public static void main(String[] args) { 

People people1 = new People(1, "Ligs", true);
People people2 = new People(2, "Songzx", false);
People people3 = new People(3, "Jinzg", true);
People people4 = new People(4, "Liuzx", false);
People people5 = new People(5, "Hedx", true);
People people6 = new People(6, "Quansm", false);
People people7 = new People(7, "Liangsz", true);
People people8 = new People(8, "Chisz", true);
ArrayList<People> list = new ArrayList<People>() { 
{ 

add(people1);
add(people2);
add(people3);
add(people4);
add(people5);
add(people6);
add(people7);
add(people8);
}};
System.out.println(list.stream().filter(People::getSex).collect(Collectors.toList()));
//[People{id=1, name='Ligs', sex=true}, People{id=3, name='Jinzg', sex=true}, People{id=5, name='Hedx', sex=true}, People{id=7, name='Liangsz', sex=true}, People{id=8, name='Chisz', sex=true}]
//过滤掉sex为false值的对象
System.out.println(list.stream().map(People::getSex).collect(Collectors.toList()));
//[true, false, true, false, true, false, true, true]
//获取list中sex属性的集合
}
}