JAVA第三季6-8完善学生选课中实现不重复ID的方法

    public void testStudentSort() {
        List<Student> studentList = new ArrayList<Student>();
        List<Integer> integer = new ArrayList<Integer>();
        Random random = new Random();
        int i;
        for (int a = 0; a < 3; a++) {
            do {
                i = random.nextInt(1000);
            } while (integer.contains(i));
            integer.add(i);
        }
        studentList.add(new Student(integer.get(0) + "", "TOM"));
        studentList.add(new Student(integer.get(1) + "", "MIKE"));
        studentList.add(new Student(integer.get(2) + "", "JACK"));
        System.out.println("------------------排序前------------------");
        for (Student student : studentList) {
            System.out.println("学生ID:" + student.getId() + "\t" + "学生姓名:" + student.getName());
        }
        System.out.println("------------------排序后------------------");
        Collections.sort(studentList);
        for (Student student : studentList) {
            System.out.println("学生ID:" + student.getId() + "\t" + "学生姓名:" + student.getName());
        }
    }