File Handling in Java

 File handling in Java refers to the process of reading from and writing to files in the computer's file system. Java provides a set of classes in the java.io package to handle file input and output operations.

To read data from a file, you can use the FileInputStream class. To write data to a file, you can use the FileOutputStream class. Both classes are used in a similar way, with the difference being that FileInputStream reads data from a file while FileOutputStream writes data to a file.

Here is an example of reading data from a file using FileInputStream:

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

public class ReadFromFileExample {
    public static void main(String[] args) {
        try {
            FileInputStream input = new FileInputStream("example.txt");
            int data;
            while ((data = input.read()) != -1) {
                System.out.print((char) data);
            }
            input.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

In this example, we create a FileInputStream object to read data from a file named "example.txt". We then use a while loop to read data from the file one byte at a time until the end of the file is reached (indicated by the -1 value). The read() method returns the next byte of data as an integer value, so we cast it to a char to print it as a character.

Here is an example of writing data to a file using FileOutputStream:

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

public class WriteToFileExample {
    public static void main(String[] args) {
        try {
            FileOutputStream output = new FileOutputStream("example.txt");
            String data = "Hello, world!";
            output.write(data.getBytes());
            output.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

In this example, we create a FileOutputStream object to write data to a file named "example.txt". We then use the write() method to write the string "Hello, world!" to the file. Note that we convert the string to a byte array using the getBytes() method before writing it to the file. Finally, we close the output stream to ensure that all data is written to the file