Java如何遍历HashMap？

Java可以使用迭代器（Iterator）或者增强for循环（for-each loop）来遍历HashMap。

使用迭代器遍历HashMap：

HashMap<String, String> map = new HashMap<>();
map.put("1", "one");
map.put("2", "two");
map.put("3", "three");

Iterator<Map.Entry<String,String>> iterator = map.entrySet().iterator();
while (iterator.hasNext()) {
    Map.Entry<String,String> entry = iterator.next();
    System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());
}

使用增强for循环遍历HashMap：

HashMap<String, String> map = new HashMap<>();
map.put("1", "one");
map.put("2", "two");
map.put("3", "three");

for (Map.Entry<String, String> entry : map.entrySet()) {
    System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());
}

两种方法的输出结果都是：

Key = 1, Value = one
Key = 2, Value = two
Key = 3, Value = three