What is the method for iterating and outputting a HashMap in Java?

In Java, there are two methods available to iterate and output a HashMap:

1. Utilizing iterators.

HashMap<String, Integer> map = new HashMap<>();
// 添加元素到map...

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();
    System.out.println("Key: " + key + ", Value: " + value);
}

1. Use a for-each loop:

HashMap<String, Integer> map = new HashMap<>();
// 添加元素到map...

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

Whether using an iterator or a for-each loop, you can retrieve key-value pairs from a HashMap by using Map.Entry. You can then use entry.getKey() to get the key and entry.getValue() to get the corresponding value. Formatting can be adjusted as needed when outputting.