java基础

关于java的集合类,以及HashMap中Set的用法!2007-08-07 16:17关于java的集合类,以及HashMap中Set的用法!  
 
2005-10-22 14:47:43 Sat | 阅读(547)次  
 
 
package com.tiantian;

import java.util.*;

public class JAVAContainer {

     
public static void main(String[] args) throws Exception {
         
//     ArrayList
         {
             ArrayList arraylist 
= new ArrayList();
             arraylist.add(
0"end");//指定索引加入值
             
//     需注意的是,如果现有2个值,我加入索引为5的那么就会出现异常
             for (int i = 0; i < 2; i++{
                 arraylist.add(i, String.valueOf(i));
             }

             System.out.println(
"ArrayList:");
             
for (int i = 0; i < arraylist.size(); i++{
                 System.out.print(arraylist.get(i) 
+ ";");
             }

             arraylist.add(
"0");//直接加入值到ArrayList的最后
             arraylist.add("0");
             System.out.print(
" ArrayList's lastIndexOf("0") is "
                     
+ arraylist.lastIndexOf("0"));
         }

         
//     Arrays
         {
             String[] array 
= new String[] "a""b""c" };
             List list 
= Arrays.asList(array);
             System.out.println(
" Arrays:");
             
for (int i = 0; i < list.size(); i++{
                 System.out.print(list.get(i) 
+ ";");
             }

             System.out.print(
" Arrays's length is " + array.length);//打印数组的长度
         }

         
//     Collections
         {
             String[] array 
= new String[] "a""b""c" };
             List list 
= Arrays.asList(array);
             Collections.fill(list, 
"Fill");//用Fill填充全部元素
             System.out.println(" Collections:");
             
for (int i = 0; i < list.size(); i++{
                 System.out.print(list.get(i) 
+ ";");
             }

             array 
= new String[] "1""2""3" };
             List list2 
= Arrays.asList(array);
             Collections.copy(list, list2);
//拷贝list2的数据进list
             System.out.println(" " + list);
             Collections.swap(list, 
21);//调换索引为1和2的元素的位置
             System.out.println(list);
         }

         
//     EventObject
         {
             String s 
= "hello";
             String s2 
= s;
             EventObject eventobject 
= new EventObject(s);//一个准容器类型,确切的归类它不是容器
             System.out.println("EventObject:");
             System.out.println(eventobject.getSource());
             System.out.println(eventobject.equals(s2));
         }

         
//     HashMap
         {
             HashMap hashmap 
= new HashMap();//一个速度最快的容器
             hashmap.put("0""c");
             hashmap.put(
"1""a");
             hashmap.put(
"2""b");
             hashmap.put(
"3""a");
             System.out.println(
"HashMap:");
             System.out.println(hashmap);
//该容器有其内部的排序方式
             Set set = hashmap.keySet();//获取全部键
             Iterator iterator = set.iterator();
             
while (iterator.hasNext()) {
                 System.out.print(hashmap.get(iterator.next()) 
+ ";");
             }

         }

         
//     HashSet
         {
             HashSet hashset 
= new HashSet();//一个绝对不能重复的类型
             hashset.add("c");
             hashset.add(
"b");
             hashset.add(
"a");
             hashset.add(
"a");
             hashset.add(
"b");
             System.out.println(
" HashSet:");
             System.out.println(hashset);
             Iterator iterator 
= hashset.iterator();//取出元素
             while (iterator.hasNext()) {
                 System.out.print(iterator.next() 
+ ";");
             }

         }

         
//     Hashtable
         {
             Hashtable hashtable 
= new Hashtable();//一个完全可以由其他容器替换的老容器类型
             hashtable.put("0""c");
             hashtable.put(
"1""a");
             hashtable.put(
"3""c");
             hashtable.put(
"2""b");
             System.out.println(
" Hashtable:");
             Enumeration enumeration 
= hashtable.elements();//获取元素,Enumeration已经不是主流,Iterator是它的下一代替代品
             while (enumeration.hasMoreElements()) {
                 System.out.print(enumeration.nextElement() 
+ ";");
             }

         }

         
//     IdentityHashMap
         {
             IdentityHashMap identityhashmap 
= new IdentityHashMap();
             identityhashmap.put(
"0""c");
             identityhashmap.put(
"1""a");
             identityhashmap.put(
"3""b");
             identityhashmap.put(
"2""a");
             System.out.println(
" IdentityHashMap:");
             System.out.println(identityhashmap);
             System.out.println(identityhashmap.containsKey(
"3"));//是否包含这个键
             System.out.println(identityhashmap.containsValue("a"));//是否包含值
             Set set = identityhashmap.entrySet();//传为Set类型
             System.out.println(set);
             set 
= identityhashmap.keySet();//全部键
             System.out.println(set);
         }

         
//     LinkedHashMap
         {
             LinkedHashMap linkedhashmap 
= new LinkedHashMap();
             linkedhashmap.put(
"0""b");
             linkedhashmap.put(
"2""a");
             linkedhashmap.put(
"1""c");
             linkedhashmap.put(
"3""b");
             System.out.println(
"LinkedHashMap:");
             System.out.println(linkedhashmap);
             System.out.println(linkedhashmap.containsKey(
"2"));//是否包含这个键
             System.out.println(linkedhashmap.containsValue("c"));//是否包含值
             Set set = linkedhashmap.keySet();
             Iterator iterator 
= set.iterator();
             
while (iterator.hasNext()) {
                 System.out.print(linkedhashmap.get(iterator.next()) 
+ ";");
             }

         }

         
//     LinkedHashSet
         {
             LinkedHashSet linkedhashset 
= new LinkedHashSet();//它包含了几种Set的属性但却没有自己的特色
             linkedhashset.add("c");
             linkedhashset.add(
"a");
             linkedhashset.add(
"a");
             linkedhashset.add(
"b");
             System.out.println(
" LinkedHashSet:");
             System.out.println(linkedhashset);
             System.out.println(linkedhashset.contains(
"a"));//是否包含对象
             Iterator iterator = linkedhashset.iterator();
             
while (iterator.hasNext()) {
                 System.out.print(iterator.next() 
+ ";");
             }

         }

         
//     LinkedList
         {
             LinkedList linkedlist 
= new LinkedList();//自由使用是它的特色
             linkedlist.add("a");
             linkedlist.add(
1"c");
             linkedlist.addLast(
"b");
             linkedlist.addFirst(
"d");
             System.out.println(
" LinkedList:");
             System.out.println(linkedlist);
             
//     linkedlist.clear();//该方法清空容器
             
//     linkedlist.remove(0);//删除索引为0的元素
             
//     linkedlist.remove("d");//删除值为d的元素
             
//     linkedlist.removeFirst();//删除第一个元素
             
//     linkedlist.removeLast();//删除最后一个元素
             for (int i = 0; i < linkedlist.size(); i++{
                 System.out.print(linkedlist.get(i) 
+ ";");
             }

         }

         
//     Stack
         {
             Stack stack 
= new Stack();//堆栈
             stack.add("b");
             stack.add(
0"c");
             stack.push(
"d");
             stack.add(
"e");
             stack.push(
"a");
             Enumeration enumeration 
= stack.elements();
             System.out.println(
" Stack:");
             
while (enumeration.hasMoreElements()) {
                 System.out.print(enumeration.nextElement() 
+ ";");
             }

             
//     后进先出
             System.out.println(" " + stack.peek());
             System.out.println(stack.pop());
             System.out.println(stack.contains(
"d"+ ";" + stack.contains("a"));//是否包含该元素,有趣的事情发生了
             System.out.println(stack.search("c"));//非常有用的属性,检索,但是由后向前的排列
         }

         
//     TreeMap
         {
             TreeMap treemap 
= new TreeMap();
             treemap.put(
"0""d");
             treemap.put(
"2""a");
             treemap.put(
"1""b");
             treemap.put(
"3""c");
             System.out.println(
" TreeMap:");//可以对键排序
             System.out.println(treemap);
             System.out.println(treemap.firstKey());
//返回第一个键
             Set set = treemap.keySet();
             Iterator iterator 
= set.iterator();
             
while (iterator.hasNext()) {
                 System.out.print(treemap.get(iterator.next()) 
+ ";");
             }

         }

         
//     TreeSet
         {
             TreeSet treeset 
= new TreeSet();//自动排序内容
             treeset.add("b");
             treeset.add(
"a");
             treeset.add(
"c");
             treeset.add(
"d");
             System.out.println(
" TreeSet:");
             System.out.println(treeset);
             System.out.println(treeset.first());
//返回第一个元素
             Iterator iterator = treeset.iterator();
             
while (iterator.hasNext()) {
                 System.out.print(iterator.next() 
+ ";");
             }

         }

         
//     Vector
         {
             Vector vector 
= new Vector();
             vector.add(
0"b");
             vector.add(
"a");
             vector.addElement(
"d");
             vector.add(
"c");
             System.out.println(
" Vector:");
             System.out.println(vector);
             vector.set(
2"h");//替换掉指定索引的元素
             System.out.println(vector);
             Object[] str 
= vector.toArray();
             
for (int i = 0; i < str.length; i++{
                 System.out.print(str[i] 
+ ";");
             }

             vector.setSize(
2);//重新设置大小为2
             System.out.println(" " + vector);
         }

         
//     WeakHashMap
         {
             WeakHashMap weakhashmap 
= new WeakHashMap();
             weakhashmap.put(
"1""b");
             weakhashmap.put(
"2""c");
             weakhashmap.put(
"0""d");
             weakhashmap.put(
"3""a");
             System.out.println(
" WeakHashMap:");
             System.out.println(weakhashmap);
             System.out.println(weakhashmap.containsKey(
"3"));//是否包含键
             System.out.println(weakhashmap.containsValue("d"));//是否包含值
             Set set = weakhashmap.entrySet();
             Iterator iterator 
= set.iterator();
             
while (iterator.hasNext()) {
                 System.out.print(iterator.next() 
+ ";");
             }

             
//     weakhashmap.remove("2");//删除该键对应的值
             
//     weakhashmap.get("1");//获取指定键的值
         }

     }

 
 
 

posted on 2008-01-25 08:45 youngturk 阅读(205) 评论(0)  编辑  收藏 所属分类: 新认识笔记


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