public String change() throws Exception {
System.out.println("********change*********");
Student student = new Student();
student.setUsername(this.username);
student.setStuid(this.stuid);
student.setPhone(this.phone);
student.setEmail(this.email);
student.setAddress(this.address);
student.setId(this.id);
ss.update(student);
return null;
}
