集合框架03：Collection使用（2）

视频链接：13.06 Collection使用（2）_哔哩哔哩_bilibilihttps://www.bilibili.com/video/BV1zD4y1Q7Fw?p=6&vd_source=b5775c3a4ea16a5306db9c7c1c1486b5

1.创建Student类

package com.yundait.Demo01;/****学生类* @author zhang*/
public class Student {private String name;private int age;public Student() {}public Student(String name, int age) {this.name = name;this.age = age;}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;}@Overridepublic String toString() {return "Student{" +"name='" + name + '\'' +", age=" + age +'}';}
}

2.创建CollectionDemo02类，实例化Student对象，演示如何在集合中添加、删除、清空、遍历、判断。

package com.yundait.Demo01;import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;public class CollectionDemo02 {public static void main(String[] args) {//新建Collection对象Collection collection = new ArrayList();Student s1 = new Student("张三", 18);Student s2 = new Student("李四", 18);Student s3 = new Student("王五", 18);Student s4 = new Student("赵六", 18);Student s5 = new Student("钱七", 18);//(1)添加数据System.out.println("--------------添加元素-----------");collection.add(s1);collection.add(s2);collection.add(s3);collection.add(s4);collection.add(s5);System.out.println("元素个数" + collection.size());System.out.println(collection.toString());//(2)删除System.out.println("--------------删除元素-----------");collection.remove(s1);System.out.println("删除后元素个数" + collection.size());System.out.println(collection.toString());//(3)清空  注意：删除或清空集合后集合对象并不会消失，因为仅仅删除对象在集合中的地址，真实的对象还在堆中；
//        collection.clear();
//        System.out.println("清空集合后元素个数" + collection.size());//（4）遍历-增强for循环方式System.out.println("--------使用增强for循环遍历---------");for (Object object : collection) {Student s = (Student) object;System.out.println(s);}//（5）遍历-iterator(迭代器)方式：hasNext();  next();  remove()//迭代过程中不能使用Collection的删除方式System.out.println("---------使用迭代器方式遍历---------");Iterator iterator = collection.iterator();while (iterator.hasNext()){Student s = (Student) iterator.next();System.out.println(s);}//（6）判断System.out.println("---------判断集合中元素---------");System.out.println(collection.contains(s2));}
}