我正在测试Java(Java8)的新主要更新,它非常有趣。我正在使用流;特别是我正在使用这个简单的代码。privatevoidgetAvg(){finalArrayListpersons=newArrayList(Arrays.asList(newMyPerson("Ringo","Starr"),newMyPerson("John","Lennon"),newMyPerson("Paul","Mccartney"),newMyPerson("George","Harrison")));finalOptionalDoubleaverage=persons.stream().filter