尝试从文本文件中获取信息并将信息拆分为数组

Question

I'm having a problem with splitting a textfile and getting the info from the textfile to an array so that i can choose the index that I want to print. The textfile is formatted like this:

X;25
Y;15

What I want to do is split the file so I can print X 25 and Y 15 or if I can get it to print just everything separately: X, 25, Y, 15

This is my code, I've tried very many different variations but right now I'm completely stuck. I've been tipped about HashMap but have no idea how to do that. Anybody who can fix my problem?

BufferedReader BR = new BufferedReader(new FileReader(new File(textfile)));

StringBuilder SB = new StringBuilder();
String assign = BR.readLine();

while((assign = BR.readLine()) != null) {
    if (assign.contains(";")) {
        SB.append(assign);   
        String assignment = SB.toString();
        String[] splitting = assignment.split(";");

        for (String s : splitting) {
            System.out.println(s);
        }  
    }
}

Answer 1

Why the whole StringBuilder complication? (not tested)

BufferedReader BR = new BufferedReader(new FileReader(new File(textfile)));

        String assign = BR.readLine(); //skips first line (if you have a header)

        while((assign = BR.readLine()) != null){

            String[] splitting= assign.split(";");

            for(int i =0; i < splitting.length; i++) {
                System.out.println(splitting[i]);
            }  

        }

Answer 2

This should work:

BufferedReader BR = new BufferedReader(new FileReader(new File(textfile)));

String assign;

while((assign = BR.readLine()) != null){

    String[] splitting= assign.split(";");

    for(int i =0; i < splitting.length; i++) {
        System.out.println(splitting[i]);
    }  

}

Answer 3

If you like to retrieve the content of the file (and not just print it), then you can try the code below. There I use a Map to store the file content and print it later.

private static final String DELIMITER = ";"; // define a constant for the used delimiter

public static void main(String args[]) throws Exception {
    final Map<String, Integer> fileContent = readFile("test.txt");
    System.out.println(fileContent);
}

public static Map<String, Integer> readFile(final String fileName) {
    final Map<String, Integer> content = new HashMap<>(); // define a map for the file content
    // try-with-resources statement so the file will be closed safely
    try (final FileReader fileReader = new FileReader(new File(fileName));
         final BufferedReader bufferedReader = new BufferedReader(fileReader)) {
        String line;
        while ((line = bufferedReader.readLine()) != null) {
            if (line.contains(DELIMITER)) {
                final String[] parts = line.split(DELIMITER);
                // the second value is an integer, so we need to convert it
                content.put(parts[0], Integer.parseInt(parts[1]));
            }
        }
    } catch (IOException e) {
        // handle exception a bit more, if you like ...
        e.printStackTrace();
    }
    return content;
}

The output will be:

{X=25, Y=15}

That means the map fileContent contains the keys "X" and "Y" and their values are 25 and 15 . If you like to get the value for "X" , then use int valueX = fileContent.get("X"); .

Your current code won't close the opened file reader, that is why I've wrapped my code in a try-with-resources statement . It will handle that for me.

If there occurs an IOException (file not found, or file couldn't be read, or something like this), then I currently just print the stacktrace. You can handle this case differently, if you like: tutorial .

Try to play with the above code to see how it works. I hope it helps you.