Java File Operations

File operations in Java.

A File is an abstract data type in Java. Creating, writing, reading, deleting, and retrieving information are all File Operations. [1]

Hierarchy of I/O Classes in Java[2]

To understand file operations we need to understand streams. [1]

Stream

A stream refers to a series of data. In Java, Streams in Java are divided into two types: Byte Stream and Character Stream.[1]

Byte Stream deals mostly with byte data. A file handling process with a byte stream is one in which the byte data is used to execute an input. Java byte streams are utilized to perform 8-bit byte input and output. For secure processes, this is the best option.[1][2]

Character Stream’s major focus is character data. A file handling procedure with a character stream is one in which an input is given and the character data is executed. Java Character streams are used to perform input and output for 16-bit Unicode [1][2]

Java File Class Methods: [1]

Boolean canRead(): Can we read the file’s data?

Boolean createNewFile(): Creates a new empty file.
Boolean canWrite(): Can we write the data into the file?

Boolean exists(): Is the specified file present?

Boolean delete(): Deletes a file.

String getName(): Finds the file name.

Boolean getAbsolutePath() : Gets the absolute pathname of the file.

Long length(): Gets the size of the file in bytes.

String[] list(): Array of the files available in the directory.

Boolean mkdir() : Creats a new directory.

Example to file operations[1]

Note: This code shows overall how and where to use file methods. Please do not use this much code in a single Try block.

import java.io.File;// File class
import java.io.IOException; // IOException for errors
class CreateFile {
public static void main(String args[]) {
try {
// Creating an object of a file
File f0 = new File(“D:FileOperationExample.txt”);
if (f0.createNewFile()) {
  System.out.println(f0.getName());
  // Getting path of the file
  System.out.println(f0.getAbsolutePath());
  // Checking whether the file is writable or not
  System.out.println(f0.canWrite());
  // Checking whether the file is readable or not
  System.out.println(f0.canRead());
  // Getting the length of the file in bytes
  System.out.println(f0.length());
  }
 // Writing the content into the FileOperationExample.txt file
fwrite.write("A named location used to store related information is referred to as a File.");
Scanner dataReader = new Scanner(f1);
while (dataReader.hasNextLine()) {
String fileData = dataReader.nextLine();
System.out.println(fileData);
}
fwrite.close(); // Closing the stream
//Using delete() in if() as depicted, shows the deleted file's name
if (f0.delete()) {
  System.out.println(f0.getName());
  }
String dirname = "/tmp/user/java/bin";
File d = new File(dirname);
d.mkdirs();// Create directory now.
file = new File("/tmp");
// List downs all the files and directories available in a directory as array of files
paths = file.list(); 

} else {
System.out.println(“File is already exist in the directory.”);
}
} catch (IOException exception) {
System.out.println(“An error is occurred.”,exception);
exception.printStackTrace();
}}}

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Source:

[1]javatpoint,(2021), File Operaitons in Java:

[https://www.javatpoint.com/file-operations-in-java]

[2]tutorialspoint,(2021), Java Files IO:

[https://www.tutorialspoint.com/java/java_files_io.htm]