写几种map集合的遍历

可以参考以下的几种遍历方式：

1. 使用Entry遍历方法：

Map<String, String> map = new HashMap<>();
map.put("key1", "value1");
map.put("key2", "value2");
map.put("key3", "value3");

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

2. 使用迭代器遍历方法：

Map<String, String> map = new HashMap<>();
map.put("key1", "value1");
map.put("key2", "value2");
map.put("key3", "value3");

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());
}

3. 遍历键集合：

Map<String, String> map = new HashMap<>();
map.put("key1", "value1");
map.put("key2", "value2");
map.put("key3", "value3");

for (String key : map.keySet()) {
    System.out.println("key: " + key + ", value: " + map.get(key));
}

4. 遍历值集合：

Map<String, String> map = new HashMap<>();
map.put("key1", "value1");
map.put("key2", "value2");
map.put("key3", "value3");

for (String value : map.values()) {
    System.out.println("value: " + value);
}