java中遍历map的方式

Java中遍历Map的方式有以下几种：

1. 使用for-each循环遍历Map的entrySet()

Map<String, Integer> map = new HashMap<>();
for (Map.Entry<String, Integer> entry : map.entrySet()) {
    String key = entry.getKey();
    Integer value = entry.getValue();
    // do something with key and value
}

2. 使用for-each循环遍历Map的keySet()

Map<String, Integer> map = new HashMap<>();
for (String key : map.keySet()) {
    Integer value = map.get(key);
    // do something with key and value
}

3. 使用迭代器遍历Map的entrySet()

Map<String, Integer> map = new HashMap<>();
Iterator<Map.Entry<String, Integer>> iterator = map.entrySet().iterator();
while (iterator.hasNext()) {
    Map.Entry<String, Integer> entry = iterator.next();
    String key = entry.getKey();
    Integer value = entry.getValue();
    // do something with key and value
}

4. 使用Java8的Lambda表达式遍历Map的entrySet()

Map<String, Integer> map = new HashMap<>();
map.forEach((key, value) -> {
    // do something with key and value
});