问从字符串中解析整数并使用另一个选择语句的值

EN

 import java.util.*;
public class InterstateLoveSong {
   public static void main(String args[]) {
      String interstate;
      int LENGTH_3_DIGIT_INTERSTATE = 3;
      int INTERSTATE_STR = 11;
      int MODULUS_2DIGIT = 5;
      int DIVIDE_3DIGIT = 100;
      int routeNumber;
      boolean exit;

      do {
          System.out.println("Please enter a US interstate highway name.");
          Scanner in = new Scanner(System.in);
          interstate = in.nextLine();
          {
              //format 1
      if (interstate.startsWith("Interstate")) {
         routeNumber = Integer.parseInt(interstate.substring(INTERSTATE_STR));  
         System.out.println("Interstate " + routeNumber);
      }
      //format 2
      else if (interstate.startsWith("I-")) {
         routeNumber = Integer.parseInt(interstate.substring(2));
         System.out.println("Interstate " + routeNumber);
      }
      //format 3
      else if (interstate.startsWith("I")) {
         routeNumber = Integer.parseInt(interstate.substring(1));
         System.out.println("Interstate " + routeNumber);        
      }
      else if (interstate.length() == LENGTH_3_DIGIT_INTERSTATE) {
         routeNumber = Integer.parseInt(interstate.substring(0));
         System.out.println("Interstate " + routeNumber);  
      }
      else if (interstate.length() == 2) {
         routeNumber = Integer.parseInt(interstate.substring(0));
         System.out.println("Interstate " + routeNumber);  
      }
      else if (interstate.length() == 1) {
         routeNumber = Integer.parseInt(interstate.substring(0));
         System.out.println("Interstate " + routeNumber);  
      }
      else {
         routeNumber = 0;
         System.exit(0);
      }

    //more information for 2 digit highways
    if (interstate.length() <= 2) {     
       if (routeNumber % MODULUS_2DIGIT == 0) {
       System.out.println("This is a long distance arterial highway.");
         }
       if (routeNumber % 2 == 0) {
       System.out.println("It is also an east-west oriented highway.");
         }
       else {
       System.out.println("It is also north-south oriented highway.");
            }  
      } 
    //more information for 3 digit highways
    if (interstate.length() == LENGTH_3_DIGIT_INTERSTATE) {
         if (routeNumber / DIVIDE_3DIGIT % 2 == 0) {
         routeNumber = routeNumber % DIVIDE_3DIGIT;
         System.out.println("This is a circumferential highway of highway " 
         + routeNumber + ".");
         }
         else {
         routeNumber = routeNumber % DIVIDE_3DIGIT;
         System.out.println("This is a spur highway of highway " 
         + routeNumber + ".");
         }
         }
       }    
      }
      while (!interstate.equals("exit"));
    }
 }