使用Stream API打印HashMap值

Question

HashMap<String, Double> missions = new HashMap<>();
missions.put("name", 1.0);
missions.put("name1", 2.0);
missions.keySet().stream().forEach(el-> System.out.println(el));

仅打印键

Answer 1

使用entrySet()（或values()如果您需要的话）代替keySet()：

Map<String, Double> missions = new HashMap<>();
missions.put("name", 1.0);
missions.put("name1", 2.0);
missions.entrySet().stream().forEach(e-> System.out.println(e));