从Java中的文本文件获取多个输入

Question

I write a program and need to generate results for different input (integer) values. which i have to read some integer numbers from several text files and store them in these variables.

• choice
• numofNodes
• numofPoints

in each file there might be multiple numbers that should be assigned to one of above variables, for example:

First text file contains five values for first variables and other two variables have one value on separate lines like below:

1 2 3 4 5
60
50

Second text file contains five values for second variables and other two variables have one value on separate lines like below:

1 
40 50 60 70 80
50

and so on..

I have no idea how to read them from text files. any helps will be appreciated.

Here's my Main class:

public static void main(String[] args)throws InterruptedException {

    // how to read numbers from different text files here
    // and store them in these variables to call func method?
    // int choice = ? 
    // int numofNode = ?
    // int numofPoint = ?

    path ob=new path(choice,numofNode,numofPoint);
    ob.func();

}

Answer 1

put files path in a string array. then you can read the files by creating an instance of java.util.Scanner class that has several methods to read file content.

all you need is to use for and for-each loops to loop through your files and read them.

here's some code that i hope helps!

/**
 * converts array of string numbers to array of integer numbers.
 *
 * @param numbers is array of strings
 * @return an integer array which is parsed from <b>numbers</b>
 *
 */
static int[] parseInt(String[] numbers) {
    return Arrays.stream(numbers).mapToInt(Integer::parseInt).toArray();
}

public static void main(String[] args) {

    // put input files path here
    String[] name_and_path_of_files = {
        "C:\\Users\\YOUR_USER\\Desktop\\input_1.txt",
        "C:\\Users\\YOUR_USER\\Desktop\\input_2.txt"
    };

    // file reader
    Scanner inputFileReader = null;
    try {

        // for all files
        for (String fileInfo : name_and_path_of_files) {

            // create reader object with file info
            inputFileReader = new Scanner(new File(fileInfo));

            int line_index = 0;

            int choices[] = null;
            int numofNodes[] = null;
            int numofPoints[] = null;

            // trying to read file content
            while (inputFileReader.hasNext()) {
                String separated_numbers[] = inputFileReader.nextLine().split(" ");
                switch (line_index) {
                    case 0:
                        choices = parseInt(separated_numbers);
                        break;
                    case 1:
                        numofNodes = parseInt(separated_numbers);
                        break;
                    case 2:
                        numofPoints = parseInt(separated_numbers);
                        break;
                }
                line_index++;
            }

            for (int choice : choices) {
                for (int numofPoint : numofPoints) {
                    for (int numofNode : numofNodes) {
                        path ob = new path(choice, numofNode, numofPoint);
                        ob.func();
                    }
                }
            }
        }
    } catch (Exception e) {
        System.out.println("Error: " + e.getMessage());
    } finally {
        if (inputFileReader != null) {
            inputFileReader.close();
        }
    }
}