Hashset HashMap跟Hashtable 实例
package com.sky.collection;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;
public class HashDemo {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Set set = new HashSet();
set.add(null);
set.add("xiaowen");
Iterator iterator=set.iterator();
while(iterator.hasNext()){
System.out.println("\n\t set中的数据:"+iterator.next());
}
Map<String,String> map=new HashMap<String,String>();
map.put("1", "xiaowen");
map.put("2", "xiaoming");
Iterator iter=map.entrySet().iterator();
while(iter.hasNext()){
Map.Entry entry = (Map.Entry) iter.next();
Object obj=entry.getValue();
Object obj2=entry.getKey();
System.out.println("\n\t map中的数据:"+obj);
}
//或者:
// for (Iterator iter2 = map.keySet().iterator();iter2.hasNext();) {
// Object key = iter2.next();
// Object val = map.get(key);
// System.out.println(key);
// }
Hashtable<String,String> table=new Hashtable<String,String>();
table.put("1", "A");
table.put("2", "B");
table.put("3", "C");
Enumeration keys=table.keys();
while(keys.hasMoreElements()){
String key=(String)keys.nextElement();
System.out.println("\n\t table中的数据:"+table.get(key));
}
Enumeration en= table.elements();
while(en.hasMoreElements()){
System.out.println("\n\t table 中的数据:"+en.nextElement());
}
}
}