How do I read a text file in Java?

Asked By: Marilo Malleshi | Last Updated: 13th June, 2020
Category: technology and computing programming languages
4.1/5 (54 Views . 35 Votes)
There are several ways to read a plain text file in Java e.g. you can use FileReader, BufferedReader or Scanner to read a text file. Every utility provides something special e.g. BufferedReader provides buffering of data for fast reading, and Scanner provides parsing ability.

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Simply so, how do you read a specific line from a text file in Java?

Java Program to read a specific line from a text file in Java

  1. import java. io.*;
  2. public class Readline {
  3. public static void main(String[] args) {
  4. String text = "";
  5. int lineNumber;
  6. try {
  7. FileReader readfile = new FileReader("myfile.txt");
  8. BufferedReader readbuffer = new BufferedReader(readfile);

Additionally, how do you read in Java? Example of Scanner Class in Java –

  1. import java.util.Scanner;
  2. class GetInputFromUser.
  3. {
  4. public static void main(String args[])
  5. {
  6. Scanner in = new Scanner(System.in);
  7. String s = in. nextLine();
  8. System.out. println("You entered string "+s);

Beside this, which class do you use to read data from a text file?

Reading a Text file in java. Java provides Reader classes to read data from various sources. You can read the contents of a file using the BufferedReader class.

What is BufferedReader in Java?

Why use BufferedReader and BufferedWriter Classses in Java. BufferedReader is a class in Java that reads text from a character-input stream, buffering characters so as to provide for the efficient reading of characters, lines and arrays. The buffer size may be specified.

28 Related Question Answers Found

How do you read a new line in Java?

To read the line and move on, we should use the nextLine() method. This method advances the scanner past the current line and returns the input that wasn't reached initially. This method returns the rest of the current line, excluding any line separator at the end of the line.

How do I use BufferedReader?

Java BufferedReader class methods
It is used for reading characters into a portion of an array. It is used to test the input stream support for the mark and reset method. It is used for reading a line of text. It is used to test whether the input stream is ready to be read.

How do I read a scanned file?

  1. import java. io. IOException; import java. util.
  2. class Main.
  3. { public static void main(String[] args) {
  4. File file = new File("doc.txt");
  5. try (Scanner sc = new Scanner(file, StandardCharsets. UTF_8. name())) { while (sc.
  6. System. out. println(sc. nextLine());
  7. } catch (IOException e) {
  8. e. printStackTrace(); }

How do you append to a text file in Java?

You can append text into an existing file in Java by opening a file using FileWriter class in append mode. You can do this by using special constructor provided by FileWriter class, which accepts a file and a boolean, which if passed as true then open the file in append mode.

How do you write to a text file in Java?


Java FileWriter class is used to write character-oriented data to a file.

Methods of FileWriter class.
Method Description
void write(char[] c) It is used to write char array into FileWriter.
void flush() It is used to flushes the data of FileWriter.
void close() It is used to close the FileWriter.

How do you read a character from a file in Java?

Read file character by character – File Handling:
  1. In file handling reading files based on the character is asked frequently in core java interviews.
  2. Step 1: Creating an object to FileReader and BufferedReader.
  3. Step 2: Reading and displaying the file charcater by character.
  4. while((c = br.read()) != -1)
  5. {

Can you read and write to the same file in Java?

Reading and writing from and to the same file in Java. txt file, to tokenize and append at the end of the same file the tokens.

What is the meaning of data file?

A data file is any file that contains information, but not code; it is only meant to be read or viewed and not executed. Programs may also rely on data files to get information. For instance, a data file may contain the settings of a program that tell the program how to display information.

How do you call a method in Java?

Call a Method
Inside main , call the myMethod() method: public class MyClass { static void myMethod() { System. out. println("I just got executed!"); } public static void main(String[] args) { myMethod(); } } // Outputs "I just got executed!"

What are Java API packages?


An application programming interface (API), in the context of Java, is a collection of prewritten packages, classes, and interfaces with their respective methods, fields and constructors.

How do I scan a string in Java?

  1. To read input: Scanner scanner = new Scanner(System. in); String input = scanner. nextLine();
  2. To read input when you call a method with some arguments/parameters: if (args. length != 2) { System. err. println("Utilizare: java Grep <fisier> <cuvant>"); System.

How do you add two numbers in Java?

Example: Program to Add Two Integers
In this program, two integers 10 and 20 are stored in integer variables first and second respectively. Then, first and second are added using the + operator, and its result is stored in another variable sum . Finally, sum is printed on the screen using println() function.

What is a scanner in Java?

Scanner is a class in java. util package used for obtaining the input of the primitive types like int, double, etc. and strings. To create an object of Scanner class, we usually pass the predefined object System.in, which represents the standard input stream.

What is a class in Java?

Classes and Objects in Java. Classes and Objects are basic concepts of Object Oriented Programming which revolve around the real life entities. Class. A class is a user defined blueprint or prototype from which objects are created. It represents the set of properties or methods that are common to all objects of one

How do you ask for input in Java?


Example 5: Get Integer Input From the User
  1. import java. Scanner;
  2. class Input {
  3. public static void main(String[] args) {
  4. Scanner input = new Scanner(System. in);
  5. print("Enter an integer: ");
  6. int number = input. nextInt();
  7. println("You entered " + number);
  8. }

How do you enter a sentence in Java?

Here's an example :
  1. import java. util. Scanner;
  2. class HelloWorld{
  3. public static void main(String []args){
  4. // Making object of Scanner class.
  5. Scanner scan = new Scanner(System.in);
  6. System. out. println("Enter your full name");
  7. //taking user input.
  8. String name = scan. nextLine();

How do you get the length of a string in Java?

String Class
  1. String Length in Java. String length returns the number of characters in a string.
  2. Syntax. int length = stringName.length();
  3. Notes. Spaces count as characters.
  4. Example. String name = "Anthony"; int nameLength = name.length(); System.out.println("The name " + name + " contains " + nameLength + "letters.");