HashMap 的两种遍历方式
<p>第一种</p>
<pre><code> Map map = new HashMap();
Iterator iter = map.entrySet().iterator();
while (iter.hasNext()) {
Map.Entry entry = (Map.Entry) iter.next();
Object key = entry.getKey();
Object val = entry.getValue();
}</code></pre>
<p>效率高</p>
<p>第二种</p>
<pre><code class="language-java"> Map map = new HashMap();
Iterator iter = map.keySet().iterator();
while (iter.hasNext()) {
Object key = iter.next();
Object val = map.get(key);
}</code></pre>
<p>效率低</p>