Java流转指定类型数组

Stream<String> stream = Stream.of("aa","bb","cc");
String[] arr = stream.toArray(String[]::new);

List<Object> newList = objectList.stream().map(Object::getVar).collect(Collectors.toList());

list.stream().sorted(Comparator.comparing(Student::getAge)) 
// 注意，排序的结果要转位list赋给自己

list.stream().collect(Collectors.joining(","));

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