How do i put a loop round this so the user can only enter a number between

Question

how do i put a loop round this so that the user can only enter a number between 1 and 3 if a number like 4 is enter it will just say something like retry
if (CA.trim().equals(ans1)){
Out = "incorrect";
else if(CA.trim().equals(ans2)){
Out = "incorrect";
else if(CA.trim().equals(ans3)){
Out = "correct";
else{
System.out.println("Enter 1 2 or 3 try doin test again");
System.out.println(Out);
byte b[] = Out.getBytes();
out1.write(b);

Answer 1

You already know the conditions so here's some pseudocode.
get input
while(input is not what I want (between one and three))
        Inform user of improper input and ask for it again
        get new input