FAQ: How To Read From A File Java?

How do you read a file in Java?

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.

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

How to read a file to string in Java

  1. import java. io. BufferedReader;
  2. import java. io. File;
  3. import java. io. FileNotFoundException;
  4. import java. io. FileReader;
  5. import java. io. IOException;
  6. class BufferedReaderExample {
  7. public static void main( String [] args) {

What is the best way to read file in Java?

If you want to read a file line by line, using BufferedReader is a good choice. BufferedReader is efficient in reading large files. The readline() method returns null when the end of the file is reached.

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How do you read a file and write to another file in Java?

Simple Program

  1. import java.io.*;
  2. class file1 {
  3. public static void main(String arg[]) {
  4. File inf = new File (“in.dat”);
  5. File outf = new File (“out.dat”);
  6. FileReader ins = null;
  7. FileWriter outs = null;
  8. try {

How do I read properties file?

Test.java

  1. import java.util.*;
  2. import java.io.*;
  3. public class Test {
  4. public static void main(String[] args)throws Exception{
  5. FileReader reader=new FileReader(“db. properties “);
  6. Properties p=new Properties ();
  7. p. load (reader);
  8. System.out.println(p.getProperty(“user”));

How do I read a scanned file?

Create a File object representing your required file. Create a Scanner class by passing the above created file object. The hasNext() verifies whether the file has another line and the nextLine() method reads and returns the next line in the file. Using these methods read the contents of the file.

How do you split a string in Java?

Following are the two variants of split () method in Java:

  1. Public String [ ] split ( String regex, int limit )
  2. public String [] split ( String regex) This variant of split method takes a regular expression as parameter, and breaks the given string around matches of this regular expression regex. Here by default limit is 0.

How do I read a file from FileInputStream?

Java FileInputStream example 1: read single character

  1. import java.io. FileInputStream;
  2. public class DataStreamExample {
  3. public static void main(String args[]){
  4. try{
  5. FileInputStream fin=new FileInputStream (“D:\testout.txt”);
  6. int i=fin. read ();
  7. System.out.print((char)i);
  8. fin.close();

What is Bufferreader class in Java?

The BufferedReader class of Java is used to read the stream of characters from the specified source (character-input stream). This class provides a method named read() and readLine() which reads and returns the character and next line from the source (respectively) and returns them.

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How do I read large files?

  1. Introduction. What’s the most efficient and easiest way to read a large file in java?
  2. Loading Whole File Into Memory. One way to load the whole file into a String is to use NIO.
  3. Loading a Binary File in Chunks.
  4. Reading a Text File Line By Line.
  5. Using a Scanner.
  6. With Java 8 Streams.

What is Java Inputstream file?

FileInputStream is useful to read data from a file in the form of sequence of bytes. FileInputStream is meant for reading streams of raw bytes such as image data. For reading streams of characters, consider using FileReader.

How do I read a large file in Java?

How to Read Large File in Java

  1. 1 Using Java API. We will cover various options how to read a file in Java efficiently using plain Java API. 1.1 Using Java BufferReader.
  2. 2 Streaming File Using Apache Commons IO. This can also be achieved by using Apache Commons IO FileUtils.lineIterator () Method.

How do you write to a file in Java?

Java FileWriter Example

  1. package com.javatpoint;
  2. import java.io.FileWriter;
  3. public class FileWriterExample {
  4. public static void main(String args[]){
  5. try{
  6. FileWriter fw=new FileWriter(“D:\testout.txt”);
  7. fw. write (“Welcome to javaTpoint.”);
  8. fw.close();

Which of these is a type of stream in Java?

Explanation: Java defines only two types of streams – Byte stream and character stream. 4. Which of these classes are used by Byte streams for input and output operation? Explanation: Byte stream uses InputStream and OutputStream classes for input and output operation.

How do I copy and paste a text file in Java?

Step 1: Create two File objects – sourceFile and destFile. Step 2: Create FileInputStream object to read the content of sourceFile in bytes. Step 3: Create FileOutputStream object to write the content to destFile.

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