Java Program to Read the Content of a File Line by Line
In this example, we will learn to read a the content of a file using various class in Java.
Example 1: Java Program to Read File Using BufferedInputStream
import java.io.BufferedInputStream;
import java.io.FileInputStream;
class Main{
public static void main(String[] args){
try {
// Creates a FileInputStream
FileInputStream file = new FileInputStream("input.txt");
// Creates a BufferedInputStream
BufferedInputStream input = new BufferedInputStream(file);
// Reads first byte from file
int i = input .read();
while (i != -1) {
System.out.print((char) i);
// Reads next byte from the file
i = input.read();
}
input.close();
}
catch (Exception e) {
e.getStackTrace();
}
}
}
Output
First Line Second Line Third Line Fourth Line Fifth Line
In the above example, we have used the BufferedInputStream
Class to read each line from the file named input.txt.
Note: In order to run this file, you should have a file named input.txt in your current working directory.
Example 2: Java Program to Read File Using BufferedReader
import java.io.FileReader;
import java.io.BufferedReader;
class Main{
public static void main(String[] args){
// Creates an array of character
char[] array = new char[100];
try {
// Creates a FileReader
FileReader file = new FileReader("input.txt");
// Creates a BufferedReader
BufferedReader input = new BufferedReader(file);
// Reads characters
input.read(array);
System.out.println("Data in the file: ");
System.out.println(array);
// Closes the reader
input.close();
}
catch(Exception e) {
e.getStackTrace();
}
}
}
Output
Data in the file: First Line Second Line Third Line Fourth Line Fifth Line
Example 3: Java Program to Read File Using Scanner
import java.io.File;
import java.util.Scanner;
class Main{
public static void main(String[] args){
try {
// create a new file object
File file = new File("input.txt");
// create an object of Scanner
// associated with the file
Scanner sc = new Scanner(file);
// read each line from file and print it
System.out.println("Reading File Using Scanner:");
while(sc.hasNextLine()) {
System.out.println(sc.nextLine());
}
// close scanner
sc.close();
} catch (Exception e) {
e.getStackTrace();
}
}
}
Output
Reading File Using Scanner: First Line Second Line Third Line Fourth Line Fifth Line
In the above example, we have created an object of File
class named file. We then created a Scanner
object associated with the file.
Here, we have used the scanner methods
- hasNextLine() – returns true if there is next line in the file
- nextLine() – returns the entire line from the file
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