迭代器模式

public class Employee {
    public String name;
    public int age;

    public Employee(String name, int age) {
        this.name = name;
        this.age = age;
    }

    @Override
    public String toString() {
        return "Employee [name=" + name + ", age=" + age + "]";
    }
}

/**
 * 迭代器接口
 */
public interface Iterator {
    boolean hasNext();
    Object next();
}

/**
 * 遍历员工的迭代器
 */
public class EmployeeIterator implements Iterator {
    private ArrayList<Employee> list;
    private int position = 0;

    public EmployeeIterator(ArrayList<Employee> list) {
        this.list = list;
    }

    @Override
    public boolean hasNext() {
        return position + 1 > list.size() ? false : true;
    }

    @Override
    public Object next() {
        return list.get(position++);
    }

}

/**
 * 要遍历的数据
 */
class Data{
    private ArrayList<Employee> employees = new ArrayList<Employee>();

    public Data() {
        employees.add(new Employee("1111", 12));
        employees.add(new Employee("2222", 123));
        employees.add(new Employee("3333", 127));
    }

    public Iterator iterator(){
        return new EmployeeIterator(employees);
    }
}

测试代码
        Data data = new Data();
        Iterator iterator = data.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next());
        }