java8 stream limit distinct map flatMap

package FanShe;

import java.util.List;

/**
* Created by meicai on 2017/11/29.
*/
public class Person {
private String name;
private Integer age;

private List<Child> childs;

public Person(String name, Integer age, List<Child> childs) {
this.name = name;
this.age = age;
this.childs = childs;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public Integer getAge() {
return age;
}

public void setAge(Integer age) {
this.age = age;
}

public List<Child> getChilds() {
return childs;
}

public void setChilds(List<Child> childs) {
this.childs = childs;
}
}