java集合类的应用

2017-12-09 16:26:15

集合类的应用

集合类的概念

  • 集合类是一些特殊的类,专门用来存放其它类对象的"容器".主要是完成一些数据库和数据结构的功能.
  • 集合类的出现,使我们的程序更加强大,更加简单.
  • 学好集合类很重要,在开发中起到至关重要的作用,大家一定要认真学习,认真体会,多复习,多练习.把集合类弄懂,学开会就容易多了.(集合类只是重点,不是难点)

集合类的分类

  • List结构集合类
    ArrayList,LinkedList,Vector,Stack
  • Map结构集合类
    HashMap,HashTable
  • Set结构集合类
    HastSet,TreeSet
  • Queue结构集合类和Queue接口

下面是简单的ArrayList增加,删除,查询相关代码

import java.util.ArrayList;

public class Main {

    public static void main(String[] args) {

        ArrayList arrayList1 = new ArrayList();
        System.out.println("大小为" + arrayList1.size());
        Xs xs1 = new Xs("张三",15,90);
        Xs xs2 = new Xs("李四",16,91);
        Xs xs3 = new Xs("王五",17,92);
        Xs xs4 = new Xs("朱六",18,93);
        arrayList1.add(xs1);
        arrayList1.add(xs2);
        arrayList1.add(xs3);

        System.out.println("大小为" + arrayList1.size());

        listAll(arrayList1);

        arrayList1.remove(0);
        System.out.println("大小为" + arrayList1.size());

        listAll(arrayList1);

        arrayList1.add(0,xs4);

        listAll(arrayList1);
    }

    private static void listAll(ArrayList arrayList1) {
        for (int i = 0; i < arrayList1.size(); i++) {
            Xs tv = (Xs) arrayList1.get(i);
            System.out.println(tv.getXingming());
        }
        System.out.println("---------");
    }
}

class Xs
{
    private String xingming;
    private int xuehao;
    private int chengji;

    public Xs(String xingming, int xuehao, int chengji) {
        this.xingming = xingming;
        this.xuehao = xuehao;
        this.chengji = chengji;
    }

    public String getXingming() {
        return xingming;
    }

    public void setXingming(String xingming) {
        this.xingming = xingming;
    }

    public int getXuehao() {
        return xuehao;
    }

    public void setXuehao(int xuehao) {
        this.xuehao = xuehao;
    }

    public int getChengji() {
        return chengji;
    }

    public void setChengji(int chengji) {
        this.chengji = chengji;
    }
}