package com.neusoft.edu.dcp.uim;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.TreeMap;
public class HashMapDemo {
//初始化
private void init(Map map,String kind)
{
if(map != null)
{
for(int i=1; i<6; i++)
{
map.put(String.valueOf(i),kind+i);
}
}
}
//结果输出
private void outPut(Map map)
{
if(map != null)
{
Object key = null;
Object value = null;
Iterator iterater = map.keySet().iterator();
while(iterater.hasNext())
{
key = iterater.next();
value = map.get(key);
System.out.print(key+": "+value+"\t");
}
System.out.println("\n");
}
}
public static void main(String args[])
{
HashMap hashmap = new HashMap();
hashmap.put("x", "1");
hashmap.put("u", "2");
hashmap.put("z", "3");
hashmap.put("h", "4");
hashmap.put("a", "5");
hashmap.put("o", "6");
hashmap.put("g", "7");
hashmap.put("u", "8");
hashmap.put("a", "9");
hashmap.put("n", "10");
hashmap.put("g", "11");
Object key = null;
Object value = null;
Iterator iterater = hashmap.keySet().iterator();
while(iterater.hasNext())
{
key = iterater.next();
value = hashmap.get(key);
System.out.print(key+": "+value+"\t");
}
System.out.println("\n");
}
//声明HashMap对象
private void setHashMap()
{
HashMap hashMap = new HashMap();
init(hashMap,"HashMap");
hashMap.put(null,"键值为空");
hashMap.put("值为空",null);
System.out.println("这是HashMap对象的键与值:");
outPut(hashMap);
}
//声明Hashtable对象
private void setHashtable(){
Hashtable hashtable = new Hashtable();
init(hashtable,"Hashtable");
//hashtable.put(null,"键值为空"); Hashtable不允许键或值为null;
//hashtable.put("值为空",null);
System.out.println("这是Hashtable对象的键与值:");
outPut(hashtable);
}
//声明LinkedHashMap对象
private void setLinkedHashMap(){
LinkedHashMap linkedHashMap = new LinkedHashMap();
init(linkedHashMap,"LinkedHashMap");
linkedHashMap.put(null,"键值为空");
linkedHashMap.put("值为空",null);
System.out.println("这是LinkedHashMap对象的键与值:");
outPut(linkedHashMap);
}
//声明TreeMap对象
private void setTreeMap(){
TreeMap treeMap = new TreeMap();
//TreeMap treeMap = new TreeMap(new MySort());//按自定义的方式排序
init(treeMap,"TreeMap");
treeMap.put("0", "后插入的值");
//treeMap.put(null,"键值为空"); TreeMap不允许键或值为null
//treeMap.put("值为空",null);
System.out.println("这是TreeMap对象的键与值:");
outPut(treeMap);
}
// public static void main(String[] args){
// HashMapDemo tm = new HashMapDemo();
// tm.setHashMap();
// tm.setHashtable();
// tm.setLinkedHashMap();
// tm.setTreeMap();
//
// Map hashMap = new HashMap();
// hashMap.put(null, "键值为null");
// hashMap.put("值为null", null);
// System.out.println("新建HashMap对象元素的记录数是:"+hashMap.size());
// hashMap.remove(null);
// System.out.println("删除键值为null的HashMap对象元素的记录数是:"+hashMap.size());
// }
}