集合方法

正常输入对象到集合里面，运用public使用类方法

import java.util.ArrayList;


public class test {
    public static void main(String[] args) {
        ArrayList<Student> list=new ArrayList<>();
        //2.创建学生对象
        Student s1=new Student("yanxiao1",1999);
        Student s2=new Student("xiaoyan2",1000);
        Student s3=new Student("yanxiao3",3999);
        //3.添加对象到集合里面
        list.add(s1);
        list.add(s2);
        list.add(s3);


        ArrayList<Student> fff1=ff(list);
        for (int i = 0; i < fff1.size(); i++) {
            Student stuu=fff1.get(i);
            System.out.println(stuu.getName()+" "+stuu.getXhao());


        }

    }


        public static ArrayList<Student> ff(ArrayList<Student> list){
            ArrayList<Student> list2=new ArrayList<>();

        for (int i = 0; i < list.size(); i++) {


            Student stu = list.get(i);
            int p=stu.getXhao();
            if(p<3000){
                list2.add(stu);
            }




        }
            return list2;


    }

}
/*
yanxiao1 1999
xiaoyan2 1000
 */