import java.util.HashMap;
import java.util.Iterator;

public class hash {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		HashMap<String, String>hm=new HashMap<String, String>();
		hm.put("100","001");
		hm.put("200","002");
		hm.put("300","003");
		hm.put("400","004");
		hm.put("500","005");
		hm.put("600","006");
		hm.put("700","007");
		hm.put("800","008");
		hm.put("900","009");
		System.out.println(hm.get("100"));
		System.out.println(hm.size());
	}
}

方式1
Iterator iterator = hm.keySet().iterator();
while(iterator.hasNext()) {
System.out.println(hm.get(iterator.next()));
}
方式2
Set set = hm.entrySet() ;
java.util.Iterator it = hm.entrySet().iterator();
while(it.hasNext()){
java.util.Map.Entry entry = (java.util.Map.Entry)it.next();
// entry.getKey() 返回与此项对应的键
// entry.getValue() 返回与此项对应的值
System.out.println(entry.getValue());
} 

hashmap的遍历