因此，我创建了这个HashMap并继续使用lambda和Stream对其进行了过滤：

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));
    }

}

如何改善我的最后一行代码，使其返回过滤后的值？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);