public void testPut() {

Scanner sc = new Scanner(System.in);

int i=0;

while(i<3) {

System.out.println("put id");

String ID = sc.next();

Student st = students.get(ID);

if(st==null)

{

System.out.println("put name");

String name = sc.next();

Student newStudent = new Student(ID,name);

students.put(ID, newStudent);

System.out.println("ok add"+students.get(ID).name);

i++;

}else {

System.out.println("get out");

}

}

}