Learn how to learn CSV file in Java with out utilizing a third-party library? FileReader Instance Tutorial

Now, let’s have a look at methods to learn a  CSV file in Java however earlier than that right here we’ve a pattern stock file, with the info within the order merchandise, amount, value

individuals.txt
Robin,31,NewYork
Tim,32,Paris
Stuwart,33,London
Craig,34,Tokyo

you’ll be able to see that the file would not have a header but when it does, you want to ignore the header, the primary line. 

We are going to first create a Particular person class in Java to signify every line in CSV file.

class Particular person {
    personal String title;
    personal int age;
    personal String metropolis;

    public Particular person(String title, int age, String metropolis) {
        tremendous();
        this.title = title;
        this.age = age;
        this.metropolis = metropolis;
    }

    public String getName() {
        return title;
    }

    public int getAge() {
        return age;
    }

    public String getCity() {
        return metropolis;
    }

    @Override
    public String toString() {
        return "Particular person [name=" + name + ", age=" + age + ", city=" + city + "]";
    }

}

Studying the CSV File

To learn the file we’re going to be utilizing a BufferedReader together with a FileReader.

We are going to learn one line at a time from the file utilizing readLine() till the Finish Of File is reached (readLine will return a null)

String.break up()

We take the string that we learn and break up it up utilizing the comma because the ‘delimiter’ (the character that tells the operate when to start out a brand new phrase and is discarded). This creates an array with the info we wish, nonetheless nonetheless in Strings, so we have to convert the values that aren’t purported to be strings into the correct values, utilizing Integer.parseInt() and Float.parseFloat()

We cross these values to the constructor for our Stock object, after which merely add that object to our ArrayList.

The complete program: (save in identical listing as others as FileFunctions.java)

Pattern Code 

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Record;


public class CSVReader {

    public static void important(String... args) {
        Record<Particular person> individuals = load("individuals.txt");
        
        
        for(Particular person p: individuals){
            System.out.println(p);
        }
    }

    
    public static Record<Particular person> load(String path) {
        
        Record<Particular person> individuals = new ArrayList<>();
        attempt {
            
            BufferedReader br = new BufferedReader(
                    new FileReader("individuals.txt"));

            
            String line = br.readLine();

            
            whereas (line != null) {

                
                String[] fields = line.break up(",");

                
                String title = fields[0];
                int age = Integer.parseInt(fields[1]);
                String metropolis = fields[2];

                
                Particular person temp = new Particular person(title, age, metropolis);

                
                individuals.add(temp);

                
                
                
                line = br.readLine();
            }

            
            br.shut();
            
        } catch (FileNotFoundException fe) {
            System.out.println("file : " + path + " not discovered");
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }

        return individuals;
    }

}

Output

Particular person [name=Robin, age=31, city=NewYork]

Particular person [name=Tim, age=32, city=Paris]

Particular person [name=Stuwart, age=33, city=London]

Particular person [name=Craig, age=34, city=Tokyo]

You’ll be able to see that how straightforward it’s to learn a CSV File in Java. It is no completely different than studying a textual content file when you use BufferedReader and FileReader accurately. However do not forget to shut the file readers, you can even use try-with-resource in order that they are going to be routinely closed as soon as you’re performed with it. 

That is all about methods to learn CSV file in Java. In case you ever want have to parse CSV file with out utilizing any third celebration library then you should use this resolution and code. It is quite simple, simply learn the CSV file line by line utilizing FileReader and BufferedReader. It is very nice and simple and you can even save on dependency administration.