How to read csv file by each row and column wise in java without using external jars

Question

Can someone tell me how can i read csv file by each row and column wise in java without using external jars.

I have tried the below code but here i am able to read only one column at a time.

public class ParseCSVs{
public static void main(String[] args) throws Exception {
    File file = new File("./input//SIMNumbers.csv");
    List<String> lines = Files.readAllLines(file.toPath(),StandardCharsets.UTF_8);
    for (String line : lines) {
        String[] array = line.split(",");
        System.out.println(array[2]);
    }
}}

Thanks in advance.

you aren't reading line by line but everything at once and iterate over the lines. this will break with large files due to massive memory consumption. — M. Deinum
– M. Deinum, Commented Dec 8, 2014 at 11:57
@M.Deinum can you tell me how can i split each row and how can i print particular row data. — Quick learner
– Quick learner, Commented Dec 8, 2014 at 12:13

M. Deinum · Accepted Answer · 2014-12-08 12:45:58Z

3

Assuming you are using Java 8 you can use streams. For this there is a lines method on the Files class. Next you need to map from a String to a String[] which you can then process.

public class ParseCSVs{

    public static void main(String[] args) throws Exception {
        File file = new File("./input//SIMNumbers.csv");
        Files.lines(file.toPath(),StandardCharsets.UTF_8)
             .substream(1)
             .map(line -> Arrays.toList(line.split(",")))
             .forEach(System.out::println);
    }
}

The code above reads the file line by line, maps the line to a String[] which in turn is turned into a List. This list is finally printed to the console.

answered Dec 8, 2014 at 12:45

M. Deinum

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3 Comments

Quick learner Over a year ago

can you please be more specific on how can i print a particular row data. let us say in row1: 1,2,3 columns and row2: 4,5,6. How can i print row2 data.Is possible can you provide me some code snippet

Quick learner Over a year ago

Hello Deinum i am expecting this. if i have 3 rows with 3 columns suppose if i enter row number 2 i want to get the entire row2 data and print on console

M. Deinum Over a year ago

Then don't use the approach here. Use a LineNumberReader and read until the lineNumber matches the line you actually want. Use it to read line by line.

lupus137 · Accepted Answer · 2014-12-08 12:15:12Z

0

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

answered Dec 8, 2014 at 12:15

lupus137

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