How To Add More Fields To Text File Java

How To Read Text File With BufferedReader In Coffee

In this article, we will read CSV file from Kaggle about Netflix'south tiptop 10 movies using BufferedReader class

Originally published at https://asyncq.com

Introduction

BufferedReader class is 1 of the most used when information technology comes to read Text files in Coffee.This class provides methods that can read characters from input stream. As proper noun says information technology buffers read characters hence efficient in reading files. In this commodity we will read csv file from Kaggle well-nigh Netflix top 10 motion picture using BufferedReader course.

Input File

I am using Netflix daily top 10 datasets from Kaggle as my input file.

BufferedReader

BufferedReader class is provided past Java SDK and we don't need any additional library. It provides enough methods to read CSV files from local disk.

Infrastructure code

To get BufferedReader Object from CSV file on Disk our lawmaking looks like below

File Reading Logic

BufferedReader class provides method readLine() to read each line from CSV file.
readLine() Reads a line of text & line is considered to be terminated past whatever one of a line feed ('\northward'), a carriage return ('\r'), or a carriage render followed immediately by a linefeed.
Each line would be Cord and we tin carve up that cord using a comma delimiter for CSV. If its tab nosotros tin can use tab separator as well.
Once we have a String array of CSV fields so its good exercise to convert that into Java POJO using mapper class. In our example , we have created a MovieMapper form that has logic to map CSV fields to Java objects.

Output

We decided to simply console impress the validated record, just in real word scenario you would either perform a certain transformation or just insert into some sink such as database.

Client code

Our client code creates 2 listing, one for fault record and other for valid records. If we come across error records we should filter it out from our input records and write to separate sink peradventure some sort of error file which performance team fellow member tin expect into afterward.
For validated records we can further process maybe do some grouping operation or some sort of farther transformation based on business organization logic and finally write it down to some Sink. Here i have merely output on console.

Listing of other methods

Read using lines() method
This method returns Stream<Cord>, suitable for reading csv reacord as a stream of record and use functional-fashion programming

Read using read() method

This method read file character by character. Since the return value is int we need to parse it to char.

Read using read(cbuff,off,len) method
Read characters into a portion of an assortment. In beneath example read character will be stored in readChar char[] array which will start reading from starting time and will read until divers length.

Determination

Java BufferedReader grade provides methods to read text file which is sufficient for many use cases. Information technology provides Stream of Input source as well which can be useful for folks who love functional programming.It is thread-safe as well which means if more than than one thread try to access Bufferedreader object it will put lock using synchronized and avoid inconsistent effect.