集合的概念

集合的概念

import java.util.ArrayList;

//数组和集合都可以存放对象类型

//集合：无限制大小

//list结构集合类：ArrayList;LinkedList;Vector;Stack

//Map结构集合类：HashMap;HashTable

//Set结构集合类：HashSet;TreeSet

//Queue（队列）结构集合类：Queue接口

public class集合 {

    public static void main(String[] args) {

        //定义ArrayList对象（存放Object类型数据）

        ArrayList al=new ArrayList();

        //显示大小

        System.out.println("集合大小："+al.size());

        Clerk cherk1=new Clerk("张三", 18, 1200);

        al.add(cherk1);

        Clerk cherk2=new Clerk("李四", 18, 1200);

        al.add(cherk2);

        System.out.println("集合大小："+al.size());

        //访问数据

//        Clerk temp=(Clerk)al.get(0);

//        System.out.println("第一个的名字是："+temp.getName());

        //遍历所有对象

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

            Clerk temp=(Clerk)al.get(i);

            System.out.println("名字是："+temp.getName());

        }

        System.out.println("删除后");

        //如何删除

        al.remove(1);

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

            Clerk temp=(Clerk)al.get(i);

            System.out.println("名字是："+temp.getName());

        }

    }

}

class Clerk{

    private String name;

    private int age;

    private float sal;

    public String getName() {

        return name;

    }

    public void setName(String name) {

        this.name = name;

    }

    public int getAge() {

        return age;

    }

    public void setAge(int age) {

        this.age = age;

    }

    public float getSal() {

        return sal;

    }

    public void setSal(float sal) {

        this.sal = sal;

    }

    public Clerk(String name, int age, float sal) {

        this.name = name;

        this.age = age;

        this.sal = sal;

    }

}