如何在java中返回经过过滤的Hashmap的值

Question

所以我创建了这个HashMap，并使用lambda和Stream进行了过滤：

public class engineMain {
public static void main(String[] args) {
CarEngine engineOne = new CarEngine("A named Engine", 2000, 8, "E10");
CarEngine engineTwo = new CarEngine("Another named Engine", 2200, 6, "E10");
String a = "Another named Engine";
HashMap<String, CarEngine> hmap = new HashMap();
hmap.put(engineOne.getEngineName(), engineOne);
hmap.put(engineTwo.getEngineName(), engineTwo);
hmap.entrySet().stream().filter(e -> e.getValue().getEngineName().contains(a))
.forEach(e -> System.out.println(e));
}
}

如何改进最后一行代码，使其返回筛选后的值？现在它返回：Another named Engine=javaapplication40.CarEngine@6ce253f1

我也尝试过这种方式

HashMap<String, CarEngine> map = new HashMap<>();
map.entrySet().stream().filter(x -> x.getKey().equals(a))
.flatMap(x -> ((Map<String, CarEngine>) x.get(a)).values().stream())
.forEach(System.out::println);

Answer 1

您似乎正在搜索：

CarEngine find = hmap.values().stream()
.filter(e -> e.getEngineName().contains(a)) 
.findFirst() 
.orElse(null);