Reading a CSV file in very simple and common in Java. You actually don't require to load any extra third party library to do this for you. CSV (comma separated value) file is just a normal plain-text file, store data in column by column, and split it by a separator (e.g comma ",").

In order to read specific columns from the CSV file, there are several ways. Simplest of all is as below:

Code to read CSV without any 3rd party library

BufferedReader br = new BufferedReader(new FileReader(csvFile));
while ((line = br.readLine()) != null) {
    // use comma as separator
    String[] cols = line.split(cvsSplitBy);
    System.out.println("Coulmn 4= " + cols[4] + " , Column 5=" + cols[5]);
}

If you notice, nothing special is performed here. It is just reading a text file, and spitting it by a separator – ",".

Consider an extract from legacy country CSV data at GeoLite Free Downloadable Databases

"1.0.0.0","1.0.0.255","16777216","16777471","AU","Australia"
"1.0.1.0","1.0.3.255","16777472","16778239","CN","China"
"1.0.4.0","1.0.7.255","16778240","16779263","AU","Australia"
"1.0.8.0","1.0.15.255","16779264","16781311","CN","China"
"1.0.16.0","1.0.31.255","16781312","16785407","JP","Japan"
"1.0.32.0","1.0.63.255","16785408","16793599","CN","China"
"1.0.64.0","1.0.127.255","16793600","16809983","JP","Japan"
"1.0.128.0","1.0.255.255","16809984","16842751","TH","Thailand"

Above code will output as below:

Column 4= "AU" , Column 5="Australia"
Column 4= "CN" , Column 5="China"
Column 4= "AU" , Column 5="Australia"
Column 4= "CN" , Column 5="China"
Column 4= "JP" , Column 5="Japan"
Column 4= "CN" , Column 5="China"
Column 4= "JP" , Column 5="Japan"
Column 4= "TH" , Column 5="Thailand"

You can, in fact, put the columns in a Map and then get the values simply by using the key.

Shishir

You can use a Scanner class: https://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html

Here is example from some page from google search: http://www.journaldev.com/2335/how-to-read-csv-file-using-java-scanner-class

You can try to format excel sheet like, adding columns to a single text by using formula like:

=CONCATENATE(A2,";",B2,";",C2,";"D2,";",E2,";",F2,";",G2,";",H2,";",I2)

and concatenate these columns by your required separator, i have used ;, here. use what you want there to be.

String filename = "matches.csv";
    File  file = new File(filename);
    try {
        Scanner sc = new Scanner(file);
        while (sc.hasNext()) {
            String data = sc.next();
            String[] values = data.split(",");
            System.out.println(data);
        }
        sc.close();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }
}

I had a similar problem in Objective C the other day, but this is how I solved it.

This method assumes you know the column number of the data you want. (I.E. if you want column 1 of 6)

Read all the rows into strings and append them into one.

Data sample: (columns 1 to 6)

1,2,3,4,5,6
13,45,63,29,10,8
11,62,5,20,13,2

String 1 = 1,2,3,4,5,6

String 2 = 13,45,63,29,10,8

String 3 = 11,62,5,20,13,2

Then you should get this:

String combined = 1,2,3,4,5,6,13,45,63,29,10,8,11,62,5,20,13,2 //add in the missing "," when you concatenate strings

Next you need to split the string into an array of all values.

Use code somewhat like this: (written off the top of my head so may be off.)

String[] values = combined.split(",");  

Now you should have something like this:

Values = `"1", "2", "3", ... etc`

The last step is to loop through the entire array and modulo for whatever column you need:

//Remember that java numbers arrays starting with 0.
//The key here is that all remainder 0 items fall into the first column.  All remainder 1 items fall into the second column.  And so on.

    for(int i = 0; i < values.length(); i++)
    {
            //Column1 - Column6 -> array lists of size values.length/number of columns
            //In this case they need to be size values.length/6
        if(i % 6 == 0)
            column1.add(values[i]);
        else if(i % 6 == 1)
            column2.add(values[i]);
        else if(i % 6 == 2)
            column3.add(values[i]);
        else if(i % 6 == 3)
            column4.add(values[i]);
        else if(i % 6 == 4)
            column5.add(values[i]);
        else if(i % 6 == 5)
                column6.add(values[i]);

    }

~~~~~~~~~~~~~~~~

Edit:

You added code to your question. Above I was saving them into memory. You just loop through and print them out. In your while loop, split each line separately into an array and then either hardcode the column number or modulo the length of the array as the index.

If you are using Java 7+, you may want to use NIO.2, e.g.:

❍ Code:

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

    File file = new File("test.csv");

    List<String> lines = Files.readAllLines(file.toPath(), 
            StandardCharsets.UTF_8);

    for (String line : lines) {
        String[] array = line.split(",", -1);
        System.out.println(array[0]);
    }

}

❍ Output:

a
1RW
1RW
1RW
1RW
1RW
1RW
1R1W
1R1W
1R1W