Java HashMap Sample 以及JAVA集合类的使用

import java.util.*;
class TestHashMap
{
public static void main(String args[])
{
HashMap hm=new HashMap();
//store some Objects.
hm.put("Rajib Sarma","100");
//duplicate keys are not allowed.
hm.put("Rajib Sarma","200");//The value "100" is replaced by "200".
hm.put("Sazid Ahmed","200");
//Display the contents of the HashMap
System.out.println("Displaying all the keys/values.\r\n");
System.out.println("Key\t\tValue\r\n");
//get all the keys
Collection c=hm.keySet();
//obtain an Iterator
Iterator i=c.iterator();
while(i.hasNext())
{
//obtain a key
Object key=i.next();
//obtain the value of the key
Object value=hm.get(key);
System.out.println(key +"\t" + value);
}//while ends
}//main ends
}

示例

HashMap staff = new HashMap();
添加关键字值对，自己写
遍历
Set entries = staff.entrySet();
Iterator iter = entries.iterator();
while(iter.hasNext())
{
Map.Entry entry = (Map.Entry)iter.next();
Object key = entry.getKey();得么关键字
Object value = entry.getValue();得到值
}