Map<String, String> map = new HashMap<String, String>();
??map.put("key1", "value1");
??map.put("key2", "value2");
??map.put("key3", "value3");
??
??//第一種：通過Map.keySet遍歷key和value
??for (String key : map.keySet()) {
???System.out.println("key= "+ key + " ?value= " + map.get(key));
??}
??
??//第二種:通過Map.entrySet使用iterator遍歷key和value
??Iterator<Map.Entry<String, String>> it = map.entrySet().iterator();
??while (it.hasNext()) {
???Map.Entry<String, String> entry = it.next();
???System.out.println("key= " + entry.getKey() + " ?value= " + entry.getValue());
??}
??
??//第三種：容量大時推薦 ?通過Map.entrySet遍歷key和value");
??for (Map.Entry<String, String> entry : map.entrySet()) {
???System.out.println("key= " + entry.getKey() + " ?value= " + entry.getValue());
??}

??//第四種：通過Map.values()遍歷所有的value，但不能遍歷key
??for (String v : map.values()) {
???System.out.println("value= " + v);
??}