获得Map的值的方法

public class Test {

    public static void main(String args[]) {
        // Map<String, String> emailsHashtable = new Hashtable<String, String>();
        Map<String, String> emails = new HashMap<String, String>();

        // 方法一: 用entrySet()
        Iterator<Map.Entry<String, String>> its = emails.entrySet().iterator();
        while (its.hasNext()) {
            Map.Entry<String, String> m = (Map.Entry<String, String>) its.next();
            System.out.println("email-" + m.getKey() + ":" + m.getValue());
        }

        // 方法二： 用entrySet(),直接循环中
        for (Map.Entry<String, String> m : emails.entrySet()) {
            System.out.println("email-" + m.getKey() + ":" + m.getValue());
        }

        // 方法三：用keySet()
        Iterator<String> it = emails.keySet().iterator();
        while (it.hasNext()) {
            String key;
            key = (String) it.next();
            System.out.println("email-" + key + ":" + emails.get(key));
        }

        // 方法四：change the values of map to collection,and use the Collection.iterator() method.
        /*
         * Map aa = new Hashtable(); for (Iterator i = aa.values().iterator(); i.hasNext();) { Object temp = i.next(); }
         */
        Map aa = new HashMap();
        for (Iterator i = aa.values().iterator(); i.hasNext();) {
            Object temp = i.next();
        }
    }
}