异常：java.lang.ArrayIndexOutOfBoundsException

Question

I am getting this error:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 2
at JavaProject.main(JavaProject.java:70)

Here is the code:

try
{
    PrintWriter writer = new PrintWriter("Gamer Report Data.txt");
    writer.println("Player: " + gamerName);
    writer.println();
    writer.println("-------------------------------");
    String[] report = gamerReport.split(gamerReport, ':');
    writer.println("Game:" + ", score=" + report[1] + ", minutes played=" + report[2] + report[3]);
    writer.close();
} catch (IOException e)
{
    System.err.println("File does not exist!");
}

I believed it to be something related to my for loop, but I have had no luck changing it around.

import java.util.Scanner;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Arrays;
import java.io.PrintWriter;

public class JavaProject {

    private static char[] input;

    @SuppressWarnings("null")
    public static void main(String[] args) {

        for (int b = 1; b < 100; b++) { 
            // this is making the code loop 100 times

            int hrs, mins;
            int[] gameCount;
            int[] minutesPlayed = new int[100];
            String gamerName, gamerReport;

            // Main data storage arrays
            String[] gameNames = new String[100];
            int[] highScores = new int[100];

            Scanner Scan = new Scanner(System.in);

            // formatting for output and input
            System.out.println("////// Game Score Report Generator \\\\\\\\\\\\");
            System.out.println("     ");

            // user enters name and then moves to next line
            System.out.println("Enter Your Name");
            gamerName = Scan.nextLine();

            // user is given an example of input format 
            System.out.println("Input Gamer Information " + "Using Format --> Game : Achievement Score : Minutes Played");
            System.out.println("    ");

            System.out.println("Game : Achievement Score : Minutes Played");
            gamerReport = Scan.nextLine();

            String[] splitUpReport; // an array of string
            splitUpReport = gamerReport.split(":"); // split the text up on the colon

            int i = 0;

            // copy data from split text into main data storage arrays 
            gameNames[i] = splitUpReport[0];
            highScores[i] = Integer.parseInt(splitUpReport[1].trim());
            minutesPlayed[i] = Integer.parseInt(splitUpReport[2].trim());

            // output to file 

            try
            {
                PrintWriter writer = new PrintWriter("Gamer Report Data.txt");
                writer.println("Player: " + gamerName);
                writer.println();
                writer.println("-------------------------------");
                String[] report = gamerReport.split(gamerReport, ':');
                writer.println("Game:" + ", score=" + report[1] + ", minutes played=" + report[2] + report[3]);
                writer.close();
            } catch (IOException e)
            {
                System.err.println("File does not exist!");
            }
        }
    }

    public static char[] getInput() {
        return input;
    }

    public static void setInput(char[] input) {
        JavaProject.input = input;
    }
}

Answer 1

The error in your code is being caused by this code in the try block:

String[] report = gamerReport.split(gamerReport, ':');

You are actually trying to split the gamerReport string using itself as a regex, with a limit of 58 , which is the numerical value of the colon.

The result of this split is 2 empty String elements, which correspond to the match happening before and after the regex, which is the string itself.

The ArrayIndexOutOfBounds exception is happening when you try to access the third element from this array:

To fix your problem, just define the report array as follows:

String[] report = gamerReport.split(':');

As @shmosel pointed out, you might also want to change your array indices here as well:

writer.println("Game:" + ", score=" + report[0] +", minutes played="+ report[1] + report[2]);

Answer 2

There are two problems with your code:

1)

String[] report = gamerReport.split(gamerReport, ':');

should be

String[] report = gamerReport.split(":");

as you did with splitUpReport (not sure why you're splitting again actually).

2) Arrays are zero-indexed, so the print statement should look like this:

writer.println("Game:" + ", score=" +report[0] +", minutes played="+ report[1] + report[2]);