使用扫描仪读取文本文件

Question

I am writing a program that takes a year as user input and returns the super bowl winner for that year (using a text file of a list of super bowl winners). It compiles correctly but when I try to execute the program I get the error:

Exception in thread "main" java.util.NoSuchElementException: No line found at java.util.Scanner.nextLine(Scanner.java:1540) at Hw5pr4.main(Hw5pr4.java:17)

What am I doing wrong?

Text file:

1967 Green Bay Packers
1968 Green Bay Packers
1969 New York Jets
1970 Kansas City Chiefs
1971 Baltimore Colts
1972 Dallas Cowboys
1973 Miami Dolphins
1974 Miami Dolphins
1975 Pittsburgh Steelers
1976 Pittsburgh Steelers
1977 Oakland Raiders
1978 Dallas Cowboys
1979 Pittsburgh Steelers
1980 Pittsburgh Steelers
1981 Oakland Raiders
1982 San Francisco 49ers
1983 Washington Redskins
1984 Los Angeles Raiders
1985 San Francisco 49ers
1986 Chicago Bears
1987 New York Giants
1988 Washington Redskins
1989 San Francisco 49ers
1990 San Francisco 49ers
1991 New York Giants
1992 Washington Redskins
1993 Dallas Cowboys
1994 Dallas Cowboys
1995 San Francisco 49ers
1996 Dallas Cowboys
1997 Green Bay Packers
1998 Denver Broncos
1999 Denver Broncos
2000 St. Louis Rams
2001 Baltimore Ravens
2002 New England Patriots
2003 Tampa Bay Buccaneers
2004 New England Patriots
2005 New England Patriots
2006 Pittsburgh Steelers
2007 Indianapolis Colts
2008 New York Giants
2009 Pittsburgh Steelers
2010 New Orleans Saints
2011 Green Bay Packers
2012 New York Giants
2013 Baltimore Ravens
2014 Seattle Seahawks
2015 New England Patriots

Source code:

import java.util.*;
import java.io.*;

public class Hw5pr4
{
    public static void main(String[] args) throws IOException{
        File winners = new File("SuperBowlWinners.txt");
        Scanner reader = new Scanner(winners);
        String[][] data = new String[49][2];

        int index = 0;
        while(reader.hasNext()){
            int yr = reader.nextInt();
            String year = Integer.toString(yr);
            data[index][0] = year;
            reader.nextLine();
            data[index][1] = reader.nextLine();
            index++;
        }

        Scanner keyboard = new Scanner(System.in);
        System.out.println("Enter a year, or to exit, enter STOP");
        String input = keyboard.nextLine();

        String winner = "Not found";
        boolean found = false;
        while(input!="STOP"){
            for(int i=0; i<49; i++){
                if(input.equals(data[i][0])){
                    winner = data[i][1];
                    found = true;
                }
            }
            System.out.println("Enter a year, or to exit, enter STOP");
            input = keyboard.nextLine();
        }
        if(found)
            System.out.println(winner);
        else
            System.out.println("Error: the year is not in the data.");
    }
}

Answer 1

First of all you are reading next line to many time:

while(reader.hasNext()){
            int yr = reader.nextInt();
            String year = Integer.toString(yr);
            data[index][0] = year;
            reader.nextLine();
            data[index][1] = reader.nextLine();
            index++;
        }

Try to remove first reader.nextLine() because you read next line in data[index][1] = reader.nextLine();

You also have another bug - while(input!="STOP"). For string comparison you must use while(!input.equals("STOP").

I also noticed that you have some other mistakes in your code. For example I think you must put this piece of code

if(found)
            System.out.println(winner);
        else
            System.out.println("Error: the year is not in the data.");

in while loop to print team for input year. You must also set found to false at the begining of every iteration of while loop. You will find other mistakes by yourself.

EDIT: here is a code sample how you should write your code in JAVA (it is not perfect but you can see what should be considered):

File winners = new File("D:\\stack.txt");
        Scanner reader = new Scanner(winners);
        HashMap<Integer, String> map = new HashMap<>();

        while (reader.hasNext()) {
            map.put(reader.nextInt(), reader.nextLine().trim());
        }

        Scanner keyboard = new Scanner(System.in);
        String input = "";
        do {
            System.out.println("Enter a year, or to exit, enter STOP");
            try {
                input = keyboard.nextLine().toUpperCase();
                if(map.containsKey(Integer.parseInt(input))){
                    System.out.println(map.get(Integer.parseInt(input)));
                } else {
                    System.out.println("Error: the year is not in the data.");
                }
            } catch (Exception e) {
                //This is just an example of handling exception, you must handle it better
                //e.printStackTrace();
                if(!input.equals("STOP"))
                    System.out.println("You must enter a valid number...");
            }
        } while (!input.equals("STOP"));

Answer 2

You fire nextLine more than once. You should store nextLine() in a variable at the start of your while() structure and use that.

If you are, by example, at line 10 you will try to read line 10 and line 11.