- _nosay
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;
}
}