1 package cn.itcast.p3.arraylist.test;

 2

 3 import java.util.ArrayList;

 4 import java.util.Iterator;

 5

 6 import com.sun.org.apache.bcel.internal.generic.NEW;

 7

 8 import cn.itcast.p.bean.Person;

 9 import sun.jvm.hotspot.ui.action.ShowAction;

10

11 public class ArrayListTest {

12

13     public static void main(String[] args) {

14         // TODO Auto-generated method stub

15         ArrayList al = new ArrayList();

16         al.add(new Person("list1",21));

17         al.add(new Person("list2",22));

18         al.add(new Person("list3",23));

19         al.add(new Person("list4",24));

20

21

22         Iterator it = al.iterator();

23         while (it.hasNext()) {

24             //System.out.println(((Person)it.next()).getName()+"::"+((Person) it.next()).getAge());

25             //list1::22

26             //list2::24 会多次调用it.next()会出错

27             Person person = (Person)it.next();

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

29         }

30

31         al.add(5);//al.add(new Integer(5)) ，jdk1.5以后可以直接用因为自动装箱

32         show(6);

33     }

34

35     private static void show(Integer num) {//Object num = 6 //new Integer(6) 只要觉得类型符合就装箱，当基本数据类型给引用数据类型时就是装箱

36         // TODO Auto-generated method stub

37         int x = num + 8;//当引用数据类型和基本数据类型作运算 拆箱

38     }

39

40 }

 1 package cn.itcast.p.bean;

 2

 3 public class Person {

 4     private String name;

 5     private int age;

 6

 7

 8     public Person() {

 9         super();

10         // TODO Auto-generated constructor stub

11     }

12     public Person(String name, int age) {

13         super();

14         this.name = name;

15         this.age = age;

16     }

17     public String getName() {

18         return name;

19     }

20     public void setName(String name) {

21         this.name = name;

22     }

23     public int getAge() {

24         return age;

25     }

26     public void setAge(int age) {

27         this.age = age;

28     }

29     //ctrl+alt+s 快捷构造set，get方法 初始化等

30 }