HashMap四种遍历方式

• for each map.entrySet()

Map<String, String> map = new HashMap<String, String>();
for (Entry<String, String> entry : map.entrySet()) {
	entry.getKey();
	entry.getValue();
}

• 显示调用map.entrySet()的集合迭代器

Iterator<Map.Entry<String, String>> iterator = map.entrySet().iterator();
while (iterator.hasNext()) {
	Map.Entry<String, String> entry = iterator.next();
	entry.getKey();
	entry.getValue();
}

• for each map.keySet()，再调用get获取

Map<String, String> map = new HashMap<String, String>();
for (String key : map.keySet()) {
	map.get(key);
}

• for each map.entrySet()，用临时变量保存map.entrySet()

Set<Entry<String, String>> entrySet = map.entrySet();
for (Entry<String, String> entry : entrySet) {
	entry.getKey();
	entry.getValue();
}