需要将 CSV 文件中的所有信息存储到 arrays

Question

I am a beginner in java and i am trying to make a program that partly requires for all the info from the CSV files to be stored into arrays. The CSV file only contains strings and has 23 rows and 3 columns. My problem is that i cannot find a way of storing everything since the array only stores the info from the last row, overwriting all the other rows.

'''

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

    String[] StringPart=null;
    File csvfile = new File("FileExample");
    Scanner dodo = new Scanner(csvfile);

    while(dodo.hasNextLine()){
        String x = dodo.nextLine();
        StringPart= x.split(",");
        }

    System.out.println(StringPart[0]+StringPart[1]+StringPart[2]);

'''

Answer 1

You are doing wrong in this line of code StringPart= x.split(","); . Here you are assigning again and again new values to StringPart . Try to add values to the array of string StringPart .

Answer 2

Since you have columns and rows, a 2d array is an appropriate representation. 2d arrays are an array of arrays. The outer array contains each row, the inner arrays contain each value.

The Files and Paths utility classes are from java.nio.file.* .

public static void main(String[] args) throws Exception {
    // read file and store contents as String
    File file = new File("csv_example.txt");
    byte[] fileData = Files.readAllBytes(Paths.get(file.getAbsolutePath()));
    String fileContent = new String(fileData);

    String[][] values; // declare values
    String[] lines = fileContent.split("\n"); // split files in to lines
    values = new String[lines.length][]; // make values large enough to hold all lines

    // for each line, add its values to an array in the 2d values array
    for(int i = 0; i < lines.length; i++)
    {
      values[i] = lines[i].split(",");
    }
}

Answer 3

In java 8, we can easily achieve it

BufferedReader br = new BufferedReader(new FileReader("test.csv"));
List<List<String>> dataList = br.lines()
    .filter(line -> line.length()>0) //ignoring empty lines
    .map(k -> Arrays.asList(k.split(",",-1))) // ,9346,Bharathi, -for this i should get [null,9346,Bharathi,null]
    .collect(Collectors.toCollection(LinkedList::new));

outer list will have rows and inner list will have corresponding column values