摘要:hashTable用法
package com.cht.commons.persistence.query;
import java.util.Hashtable;
import java.util.Iterator;
public class testCollection {
public static void main(String[] args) {
// 特点:
// 查找速度快,遍历相对慢
// 键值不能有空指针和重复数据
// 创建
Hashtable<Integer, String> ht = new Hashtable<Integer, String>();
// 添值
ht.put(1, "Andy");
ht.put(2, "Bill");
ht.put(3, "Cindy");
ht.put(4, "Dell");
ht.put(5, "Felex");
ht.put(6, "Edinburg");
ht.put(7, "Green");
// 取值
String str = ht.get(1);
System.out.println(str);// Andy
// 对键进行遍历
Iterator it = ht.keySet().iterator();
while (it.hasNext()) {
Integer key = (Integer) it.next();
System.out.println(key);
}
// 对值进行遍历
Iterator it2 = ht.values().iterator();
while (it2.hasNext()) {
String value = (String) it2.next();
System.out.println(value);
}
// 取Hashtable记录数
ht = new Hashtable<Integer, String>();
ht.put(1, "Andy");
ht.put(2, "Bill");
ht.put(3, "Cindy");
ht.put(4, "Dell");
ht.put(5, "Felex");
ht.put(6, "Edinburg");
ht.put(7, "Green");
int i = ht.size();// 7
// 删除元素
ht = new Hashtable<Integer, String>();
ht.put(1, "Andy");
ht.put(2, "Bill");
ht.put(3, "Cindy");
ht.put(4, "Dell");
ht.put(5, "Felex");
ht.put(6, "Edinburg");
ht.put(7, "Green");
ht.remove(1);
ht.remove(2);
ht.remove(3);
ht.remove(4);
System.out.println(ht.size());// 3
it = ht.values().iterator();
while (it.hasNext()) {
// Get value
String value = (String) it.next();
System.out.println(value);
}
}
}
ref:http://www.blogjava.net/junglesong/archive/2008/02/21/181184.html