快速遍历Map

方式一：使用entrySet()与forEach循环

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

方式二：使用keySet()与forEach循环

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

方式三：使用forEach与Lambda循环

map.forEach((key, value) -> 
    System.out.println("Key: " + key + ", Value: " + value)
);

方式四：使用迭代器与entrySet()或keySet()

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

方式五：使用Stream()流Api

map.entrySet().stream()
    .forEach(entry -> 
        System.out.println("Key: " + entry.getKey() + ", Value: " + entry.getValue())
    );
 
// 或者并行流（大数据量时可能提升性能）
map.entrySet().parallelStream()
    .forEach(entry -> 
        System.out.println("[Parallel] Key: " + entry.getKey() + ", Value: " + entry.getValue())
    );