Java how to read file

How do I read a large file in Java?

First off, you could just load the whole file into memory if the file is small enough. For large files, you need to process chunks. A binary file can be processed in chunks of say, 4kB. A text file can be processed line by line.

How do I read a file in file reader?

In this example, we are reading the data from the text file testout. txt using Java FileReader class.

  1. package com.javatpoint;
  2. import java.io.FileReader;
  3. public class FileReaderExample {
  4. public static void main(String args[])throws Exception{
  5. FileReader fr=new FileReader(“D:\testout.txt”);
  6. int i;
  7. while((i=fr.read())!=-

How do you read the last line of a file in Java?

Java program to read last line of the file using RandomAccessFile. Line – This is the fourth line. Here you get the file length and then using the seek method move the pointer to that point (end of the file). From there you start reading backward char by char.

How do you handle big data in Java?

Provide more memory to your JVM (usually using -Xmx / -Xms ) or don’t load all the data into memory. For many operations on huge amounts of data there are algorithms which don’t need access to all of it at once. One class of such algorithms are divide and conquer algorithms.

What is buffer reader in Java?

The Java.io.BufferedReader class reads text from a character-input stream, buffering characters so as to provide for the efficient reading of characters, arrays, and lines.Following are the important points about BufferedReader − The buffer size may be specified, or the default size may be used.

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How do I read a notepad file in Java?

Different ways of Reading a text file in Java

  1. Using BufferedReader: This method reads text from a character-input stream. …
  2. Using FileReader class: Convenience class for reading character files. …
  3. Using Scanner class: A simple text scanner which can parse primitive types and strings using regular expressions. …
  4. Using Scanner class but without using loops:

How do you write to a file in Java?

txt using Java FileWriter class.

  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();

How do you read and print a string in Java?

Example of nextLine() method

  1. import java.util.*;
  2. class UserInputDemo1.
  3. {
  4. public static void main(String[] args)
  5. {
  6. Scanner sc= new Scanner(System.in); //System.in is a standard input stream.
  7. System.out.print(“Enter a string: “);
  8. String str= sc.nextLine(); //reads string.

How do you handle a large amount of data?

Photo by Gareth Thompson, some rights reserved.

  1. Allocate More Memory. …
  2. Work with a Smaller Sample. …
  3. Use a Computer with More Memory. …
  4. Change the Data Format. …
  5. Stream Data or Use Progressive Loading. …
  6. Use a Relational Database. …
  7. Use a Big Data Platform. …
  8. Summary.

29 мая 2017 г.

How do you process a large amount of data?

Here are some ways to effectively handle Big Data:

  1. Outline Your Goals. …
  2. Secure the Data. …
  3. Keep the Data Protected. …
  4. Do Not Ignore Audit Regulations. …
  5. Data Has to Be Interlinked. …
  6. Know the Data You Need to Capture. …
  7. Adapt to the New Changes. …
  8. Identify human limits and the burden of isolation.

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