HashMap集合的三种遍历方式（案例）``` Map map = new HashMap<>(); map.put("

Map<String,Integer> map = new HashMap<>();
map.put("java",10);
map.put("C++",20);
map.put("js",30);
Set<String> set = map.keySet();//键值对遍历HashMap集合
for (String s : set) {
    int value = map.get(s);
    System.out.println(s+"->"+value);
    
}

Set<Map.Entry<String, Integer>> entries = map.entrySet();//键找值遍历HashMap集合
for (Map.Entry<String, Integer> entry : entries) {
    String key = entry.getKey();
    int value = entry.getValue();
    System.out.println(key+"->"+value);
}

map.forEach((String k, Integer v) -> { System.out.println(k+"->"+v); });//forEach方法遍历HashMap集合