小编Gha*_*sar的帖子

当存储到学生可能碰巧有相同的ID,所以我怎么能避免重复,我已经尝试了while循环和每个循环,但它不起作用

public void addStudent(Student student)

{

student.setId(ganerateNewRandom("aa", 2));

students.add(student);

}






  public String ganerateNewRandom(String prefix, int number)
 {

  Random random = new Random();

    StringBuffer ret = new StringBuffer(prefix);


    for(int i=0;i<number;i++) ret.append(random.nextInt(10));


    return ret.toString();


}