public class Student {

     private String name;

     private int age;

     public Student() {

        super();

    }

     public Student(String name, int age){

         super();

         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;

    }

}

===========================================

public class Dome1 {

    public static void main(String[] args) {

        Collection c = new ArrayList();

        Student s = new Student("张三",19);

        Student s1 = new Student("李四",29);

        c.add(s);

        c.add(s1);

        c.add(new Student("王五",18));

        c.add(new Student("赵六",28));

        //遍历方式1

        Object[] obj = c.toArray();

        for(int x=0;x<obj.length;x++){

            Student stu = (Student) obj[x];

            System.out.println(stu.getName()+":"+stu.getAge());

        }

        //便利方式2

        Iterator it = c.iterator();

        while(it.hasNext()){

            Student stu = (Student) it.next();

            System.out.println(stu.getName()+":"+stu.getAge());

        }

        //便利方式3

//        Student[] stu = (Student[]) c.toArray();

        for(Object st :obj){

            System.out.println(((Student) st).getName()+":"+((Student) st).getAge());

        }

    }

}