コレクションの使用（2）：学生情報を保存する

package collectionStudy;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;

/**
 * Collection的使用：保存学生信息
 * @create 2021-02-25 9:21
 */
public class Demo02 {
    
    
    public static void main(String[] args) {
    
    
        //新建Collection对象
        Collection collection=new ArrayList();
        Student s1 = new Student("张三",20);
        Student s2 = new Student("罗斯",22);
        Student s3 = new Student("王二",10);
        //1添加数据
        collection.add(s1);
        collection.add(s2);
        collection.add(s3);
        System.out.println("元素个数："+collection.size());
        System.out.println(collection.toString());
        //2删除
        collection.remove(s1);
        System.out.println("删除之后："+collection.size());
        //3遍历
        //3.1增强for
        System.out.println("-------增强for-------");
        for (Object object:collection
             ) {
    
    Student s=(Student) object;
            System.out.println(s.toString());

        }
        //3.2迭代器：hasNext();next();remove();迭代过程中不能使用collection的删除方法
        System.out.println("-------迭代器-------");
        Iterator it =collection.iterator();
        while (it.hasNext()){
    
    
            Student s=(Student)it.next();
            System.out.println(s.toString());
        }
        //4判断
        System.out.println(collection.contains(s2));
        System.out.println(collection.isEmpty());
    }
}

学生クラス

package collectionStudy;

/**
 * 学生类
 * @create 2021-02-25 9:21
 */
public class Student {
    
    
    private  String name;
    private  int age;

    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;
    }

    @Override
    public String toString() {
    
    
        return "Student{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}