public static void main(String[] args) {
        Random r = new Random();
        DelayQueue<Student> students = new DelayQueue<Student>();
        ExecutorService exec = Executors.newCachedThreadPool();
        for(int i = 0; i < STUDENT_SIZE; i++){
            students.put(new Student("学生" + ( i + 1), 3000 + r.nextInt(9000)));
        }
        students.put(new Student.EndExam(12000,exec));//1200为考试结束时间
        exec.execute(new Teacher(students, exec));

    }