Parsing a text file using java bufferedReader and Scanner

Question

I have the following config file that I am trying to use to set global variables in my program

OUTPUT_FILE_PATH = filename2.txt
MAX_CRAWL_DEPTH = 2
NUMBER OF CRAWLERS = 10
SEED_URL = https://www.lehigh.edu/home
DOMAIN = lehigh.edu
DELAY = 10

To parse this text file I am using this

String line = "";
            BufferedReader buffRead = new BufferedReader(new FileReader((CONFIG_FILE_PATH)));
            Scanner charlie = new Scanner(line);

            String varName;
            while ((line = buffRead.readLine()) != null){
                System.out.println(line);
                charlie.useDelimiter(" = ");
                varName = charlie.next();
                System.out.println(varName);



                if (varName == "OUTPUT_FILE_PATH")
                    OUTPUT_FILE_PATH = charlie.next();
                else if (varName == "MAX_CRAWL_DEPTH")
                    MAX_CRAWL_DEPTH = charlie.nextInt();
                else if (varName == "NUMBER_OF_CRAWLERS")
                    NUMBER_OF_CRAWLERS = charlie.nextInt();
                else if (varName == "SEED_URL")
                    SEED_URL = charlie.next();
                else if (varName == "DOMAIN")
                    DOMAIN = charlie.next();
                else if (varName == "DELAY")
                    delay = charlie.nextInt();
            }

I get this output when running the code

OUTPUT_FILE_PATH = filename2.txt
Exception in thread "main" java.util.NoSuchElementException
        at java.base/java.util.Scanner.throwFor(Scanner.java:937)
        at java.base/java.util.Scanner.next(Scanner.java:1478)
        at Globals.setGlobals(Globals.java:44)

Line 44 is where I set varName = charlie.next(); Any reason why this would be wrong? Any other tips on how to go about parsing this file? I feel like my if statements is not the best way to do it.

Spectric · Accepted Answer · 2020-10-18 21:37:30Z

1

It's throwing the NoSuchElementException because the String you are providing in the instance of the scanner on this line:

Scanner charlie = new Scanner(line);

Is actually just:

Scanner charlie = new Scanner("");

Since you never modified line after you set it to "".

You should be doing the following:

Scanner charlie = new Scanner(System.in);

Also, a Scanner instance doesn't accept a String.

answered Oct 18, 2020 at 21:37

Spectric

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lolitsjef · Accepted Answer · 2020-10-18 21:39:30Z

0

I needed to define the scanner inside the while loop after line got updated each time, thanks everyone

answered Oct 18, 2020 at 21:39

lolitsjef

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