1.创建对象
ArrayList list = new ArrayList<>();

2.添加
list.add(“ “);

3.删除
list.remove(“ “);
此处可以填具体存在的值或者是索引

4.修改
list.set( 索引, 要修改的值)

5.查询
list.get( 索引)

实例：
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Scanner;

public class Main {
public static void main(String[] args) {
//1.创建集合
ArrayList list = new ArrayList<>();
//2.创建学生对象
Student s1 = new Student(“日奈”,17);
Student s2 = new Student(“伊吹”,11);
//3.添加元素
list.add(s1);
list.add(s2);

    //键盘输入
    Student s3 = new Student();
    Scanner sc = new Scanner(System.in);
    System.out.println("输入姓名");
    String name = sc.next();
    System.out.println("输入年龄");
    int age = sc.nextInt();
    s3.setName(name);
    s3.setAge(age);
    list.add(s3);

    //5.遍历集合
    for (int i = 0; i < list.size(); i++) {
        Student stu = list.get(i);
        System.out.println(stu.getName() + "," + stu.getAge());
    }
}

}