File processing and CRUD operations in Java

Record handling is a fundamental aspect of programming that allows us to connect to files stored on the computer. In Java, file processing is made convenient through the Record class and other operations, namely CRUD (create, read, update, delete) operations. In this article, we will explore the different ways to perform file processing in Java, each with its own advantages and use cases.

Syntax

Before we delve into the different methods of file manipulation, let’s familiarize ourselves with the basic language constructs for creating records in Java.

File file = new File("path/to/file.txt");

Syntax explanation

To start processing Java records, we should use moment expressions to record basic classes. The Record class allows us to create instances representing records by passing a file path as a parameter. Once we have the record object, we can perform various operations such as reading, writing, updating, and deleting the file.

Method 1: Using FileReader and FileWriter

Algorithm

• ##Create a FileReader object to read from an existing file.

• Create a FileWriter object to write to the file.

• Use a loop to read from the input file and write to the output file until the end of the file is reached.

• Close the FileReader and FileWriter objects to release system resources.

Example

import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class FileHandler {
   public static void main(String[] args) {
      try {
         FileReader reader = new FileReader("input.txt");
         FileWriter writer = new FileWriter("output.txt");

         int character;
         while ((character = reader.read()) != -1) {
            writer.write(character);
         }

         reader.close();
         writer.close();
      } catch (IOException e) {
         e.printStackTrace();
      }
   }
}

Output

Hello, world! This is a sample text file used for testing the file handling code. It contains some random sentences and paragraphs. Feel free to modify and experiment with it as needed. Have a great day!

Explanation

In this method we use FileReader class to read from existing record Read and input into the record using the FileWriter class. We create FileReader and FileWriter objects, specify the names of the input and output records, and then use a while loop to read characters from the input record and input them into the output record. Finally, we close the FileReader and FileWriter objects to release system resources.

Methods using BufferedReader and BufferedWriter

Algorithm

##Create a BufferedReader object to read from an existing file.
Create a BufferedWriter object to write to the file.
Use a loop to read from the input file and write to the output file until the end of the file is reached.
Close the BufferedReader and BufferedWriter objects to release system resources.
Example

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class FileHandler {
   public static void main(String[] args) {
      try {
         BufferedReader reader = new BufferedReader(new FileReader("input.txt"));
         BufferedWriter writer = new BufferedWriter(new FileWriter("output.txt"));

         String line;
         while ((line = reader.readLine()) != null) {
            writer.write(line);
            writer.newLine();
         }

         reader.close();
         writer.close();
      } catch (IOException e) {
         e.printStackTrace();
      }
   }
}

Output

Hello, world! This is a sample text file used for testing the file handling code. It contains some random sentences and paragraphs. Feel free to modify and experiment with it as needed. Have a great day!

Explanation

In this approach we utilize BufferedReader class to read from existing records Read the data and write the data to the record using the BufferedWriter class. We create BufferedReader and BufferedWriter objects, specify the names of the input and output records, and then use a loop to read lines from the input records and write them to the output records. By using the readLine() method, text input can be processed more efficiently. Finally, we close the BufferedReader and BufferedWriter objects to release system resources.

Method 3: Using FileInputStream and FileOutputStream

Algorithm

Create a FileInputStream object to read from an existing file.
Create a FileOutputStream object to write to the file.
Use a loop to read from the input file and write to the output file until the end of the file is reached.
Close the FileInputStream and FileOutputStream objects to release system resources.
Example

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class FileHandler {
   public static void main(String[] args) {
      try {
         FileInputStream inputStream = new FileInputStream("input.txt");
         FileOutputStream outputStream = new FileOutputStream("output.txt");

         int bytesRead;
         byte[] buffer = new byte[1024];
         while ((bytesRead = inputStream.read(buffer)) != -1) {
            outputStream.write(buffer, 0, bytesRead);
         }

         inputStream.close();
         outputStream.close();
      } catch (IOException e) {
         e.printStackTrace();
      }
   }
}

Output

Hello, world! This is a sample text file used for testing the file handling code. It contains some random sentences and paragraphs. Feel free to modify and experiment with it as needed. Have a great day!

Explanation

Here we use FileInputStream to learn from existing records and use FileOutputStream input into the record. We create FileInputStream and FileOutputStream objects, specify the names of the input and output records, and then use a loop to read bytes from the input records and input them into the output records. Buffers help read and write data efficiently. Finally, we close the FileInputStream and FileOutputStream objects to release system resources.

Method 4: Use Files.copy() and Files.delete()

Algorithm

Use Files.copy() method to delete a file Copy the contents to another file.
Use the Files.delete() method to delete files.
Example

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class FileHandler {
   public static void main(String[] args) {
      try {
         Path source = Paths.get("input.txt");
         Path destination = Paths.get("output.txt");
         Files.copy(source, destination);

         Files.delete(source);
      } catch (IOException e) {
         e.printStackTrace();
      }
   }
}

Output

Hello, world! This is a sample text file used for testing the file handling code. It contains some random sentences and paragraphs. Feel free to modify and experiment with it as needed. Have a great day!

Explanation

In this method, we utilize the java.nio.file package Records class to copy and delete files. We use the Paths class to specify the paths of the source and target files, and then use the copy() method to copy the contents of the source file to the target file. After the copy operation is completed, we delete the source file using the delete() method. This method provides a fast and efficient way to perform file copy and delete operations.

Conclusion

Record processing is a fundamental part of Java programming, and understanding the different ways to perform CRUD operations can greatly improve your ability to handle records. In this article, we explored four methods of record processing in Java, each with its own advantages and use cases. By using classes like FileReader, FileWriter, BufferedReader, BufferedWriter, FileInputStream, FileOutputStream, and Records, we can easily create, read, update, and delete records in Java programs. By using these methods for testing, you can create powerful record processing capabilities to meet your specific application needs.

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