集合框架-ArrayList集合儲存自定義物件
阿新 • • 發佈:2021-10-20
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 publicView Codestatic 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 2122 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 會多次呼叫it.next()會出錯 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以後可以直接用因為自動裝箱 32 show(6); 33 } 34 35 private static void show(Integer num) {//Object num = 6 //new Integer(6) 只要覺得型別符合就裝箱,當基本資料型別給引用資料型別時就是裝箱 36 // TODO Auto-generated method stub 37 int x = num + 8;//當引用資料型別和基本資料型別作運算 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 快捷構造set,get方法 初始化等 30 }View Code