泛型集合

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

public  class Demo01 {
    public static void main(String[] args) {
        //泛型的好处：1.提高代码的重用性  2.防止类型转换异常，提高代码的安全性
        
        //泛型集合
        ArrayList<String> arrayList = new ArrayList<>();//不能再添加String类型之外的其他引用类型
        arrayList.add("123");
        arrayList.add("456");
        for (String s:
             arrayList) {
            System.out.println(s);
        }

        ArrayList<Student> arrayList1 = new ArrayList<>();
        Student s1 = new Student("张三", 16);
        Student s2 = new Student("李四", 16);
        Student s3 = new Student("王五", 16);
        arrayList1.add(s1);
        arrayList1.add(s2);
        arrayList1.add(s3);

        Iterator<Student> iterator = arrayList1.iterator();
        while (iterator.hasNext()){
            Student next = iterator.next();
            System.out.println(next);
        }
    }
}