遍历map

map.forEach((k, v) -> System.out.println("key:value = " + k + ":" + v));

map转list

map.entrySet().stream().map(e -> new Person(e.getKey(),e.getValue())).collect(Collectors.toList());

list转map

Map<Integer, String> result1 = list.stream().collect(Collectors.toMap(Hosting::getId, Hosting::getName));