以这种方式将子类转换为父类是否有意义？

Question

class Student{ 
} 

class CollegeStudent extends Student{ 
} 

我有CollegeStudent的名单，我想将其转换为学生的名单：

List<CollegeStudent> collegeStudents = getStudents(); 
List<Student> students = new ArrayList<Student>(); 
for(CollegeStudent s : collegeStudents){ 
    students.add(s); 
} 

这是适当的方式来达到目的？目的是什么？我想这样做的原因是我需要创建另一个类，它将Student的列表作为参数，而不是CollegeStduent的列表。

Answer 1

这很好，但也有一些短方式：

// Using the Collection<? extends E> constructor: 
List<Student> studentsA = new ArrayList<>(collegeStudents); 
// Using Collections.unmodifiableList which returns 
// an unmodifiable view of the List<CollegeStudent> 
// as a List<Student> without copying its elements: 
List<Student> studentsB = Collections.unmodifiableList(collegeStudents); 
// Older versions of Java might require a type 
// witness for Collections.unmodifiableList: 
List<Student> studentsC = Collections.<Student>unmodifiableList(collegeStudents);