File Handling Concept in Java?

File:-

it is a collection of records that are used to store data permanently in computer hard disk.
If we want to store program output in computer disk then we can use file handling concept in the project.
operating system use file handling concept by default to store data or record in the harddisk.

All DBMS Server internally use file handling concept to store data.
for example, if we want to create our resume then we create a doc file and save into the operating system.
this task will be managed by file handling.

File handling:-

File handling means to work on file and store data. means File handing provide create a file, write a file, read a file, append file, destroy a file , copy a file, rename file these all task will be managed by this.

Java provides io package to perform file handling tasks.

File

Text File (.txt,.doc,.docx,xlx) Binary File (Image File, Audio file, Video file, Pdf file)

FileWriter FileOutputStream
FileReader FileInputStream
BufferedWriter ObjectInputStream
BufferedReader ObjectOutputStream

Simple Program to Write Data on File?

import java.io.*;

import java.util.*;

class Fileoperation

{

public static void main(String args[]) throws IOException

{

Scanner sc = new Scanner(System.in);

String s;

File obj = new File("hello.txt");

// FileWriter fw = new FileWriter(obj); //write mode

FileWriter fw = new FileWriter(obj,true); //append mode

BufferedWriter bw = new BufferedWriter(fw);

bw.newLine();

System.out.println("Enter content");

s=sc.nextLine();

bw.write(s);

bw.close();

fw.close();

}

Program to read file:-

import java.io.*;

import java.util.*;

class Fileoperation

{

public static void main(String args[]) throws IOException

{

Scanner sc = new Scanner(System.in);

String s,s1="";

File obj = new File("hello.txt");

FileReader fr = new FileReader(obj);

BufferedReader br = new BufferedReader(fr);

while((s=br.readLine())!=null)

{

s1 =s1 + s;

}

System.out.print(s1);

br.close();

fr.close();

}

WAP to Create, Write, and Read Text File?

import java.io.*;
/**
*
* @author SHIVA
*/
public class FileHandlingProgram {
File f;
FileWriter fw;
FileReader fr;
BufferedReader br;
void createFile() throws IOException
{
f= new File("e://abc.txt");
if(!f.exists())
f.createNewFile();

}
void writeFile() throws IOException
{
fw = new FileWriter(f);
fw.write("welcome in SCS");
fw.close();

}
void readFile() throws IOException
{
fr = new FileReader(f);
br = new BufferedReader(fr);
String s="",s1="";
while((s1=br.readLine())!=null)
{
System.out.println(s1);

}
br.close();
fr.close();

}
public static void main(String[] args) throws IOException {
FileHandlingProgram obj = new FileHandlingProgram();
obj.createFile();
obj.writeFile();
obj.readFile();

}

}

..................................................................................................................................................
Program to perform Create, Write, Append, Read and Delete Text File Complete Code

import java.io.*;
import java.nio.file.Files;
import java.nio.file.Paths;
/**
*
* @author SHIVA
*/
public class FileHandlingProgram {
File f;
FileWriter fw;
BufferedWriter bw;
FileReader fr;
BufferedReader br;
void createFile() throws IOException
{
f= new File("e://abc.txt");
if(!f.exists())
f.createNewFile();

}
void writeFile() throws IOException
{

fw = new FileWriter(f);
InputStreamReader ir = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(ir);
System.out.println("Enter name ");
String s = br.readLine();
bw = new BufferedWriter(fw);
bw.write(s);
System.out.println("Enter phone ");
String s1 = br.readLine();
bw.newLine();
bw.write(s1);
bw.close();
fw.close();

}
void appendFile() throws IOException
{

fw = new FileWriter(f,true);
InputStreamReader ir = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(ir);
bw = new BufferedWriter(fw);
bw.newLine();
System.out.println("Enter name ");
String s = br.readLine();

bw.write(s);
System.out.println("Enter phone ");
String s1 = br.readLine();
bw.newLine();
bw.write(s1);
bw.close();
fw.close();

}
void readFile() throws IOException
{
fr = new FileReader(f);
br = new BufferedReader(fr);
String s="",s1="";
while((s1=br.readLine())!=null)
{
System.out.println(s1);

}
br.close();
fr.close();

}
void deleteFileData() throws IOException
{
fw = new FileWriter(f);
fw.write("");
fw.close();

}
void removeFile() throws IOException
{

if(Files.deleteIfExists(Paths.get("e://abc.txt")))
{
System.out.println("File Deleted Successfully");
}

}
public static void main(String[] args) throws IOException {
FileHandlingProgram obj = new FileHandlingProgram();
// obj.createFile();
// obj.appendFile();

// obj.deleteFileData();
obj.removeFile();
// obj.writeFile();
// obj.readFile();

}

}

Binary File Operation:-

Binary means file which will take input using the binary format with 0 and 1.

It is used to manage all input data in a byte pattern.

Classes for Binary Operation:-

1 FileInputStream :- Read Data in Byte Pattern

2 FileOutputStream :- Write Data in Byte Pattern

................................................................................................................................

import java.io.*;
import java.nio.file.Files;
import java.nio.file.Paths;
/**
*
* @author SHIVA
*/
public class FileHandlingProgram {
File f;
FileOutputStream fw;
FileInputStream fr;
void createFile() throws IOException
{
f= new File("e://abc.txt");
if(!f.exists())
f.createNewFile();

}
void writeFile() throws IOException
{

fw = new FileOutputStream(f);
InputStreamReader ir = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(ir);
System.out.println("Enter data ");
String s = br.readLine();
byte arr[] = s.getBytes();
fw.write(arr);
fw.close();

}
void appendFile() throws IOException
{

fw = new FileOutputStream(f,true);
InputStreamReader ir = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(ir);
System.out.println("Enter data ");
String s = br.readLine();
byte arr[] = s.getBytes();
fw.write(arr);
fw.close();

}
void readFile() throws IOException
{
fr = new FileInputStream(f);
byte arr[] = new byte[1000];
int s=0,s1=0;
while((s1=fr.read(arr))!=-1)
{
System.out.println(new String(arr));

}

fr.close();

}
void deleteFileData() throws IOException
{
fw = new FileOutputStream(f);
String s="";

fw.write(s.getBytes());
fw.close();

}
void removeFile() throws IOException
{

if(Files.deleteIfExists(Paths.get("e://abc.txt")))
{
System.out.println("File Deleted Successfully");
}

}
public static void main(String[] args) throws IOException {
FileHandlingProgram obj = new FileHandlingProgram();
obj.createFile();
// obj.appendFile();

// obj.deleteFileData();
//obj.removeFile();
obj.writeFile();
obj.readFile();

}

}

WAP to create a mark sheet for multiple students and display total pass and fail a student with individual mark sheet and aggregate record.

Uncontrolled form input in React-JS

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