getChannel() Method in Java

The getChannel() method is defined in Java.io.FileInputStream class. The getChannel() method is the gateway to creating a FileChannel instance for a file. It is typically available on classes like FileInputStream, FileOutputStream, and RandomAccessFile.

FileInputStream

We can use FileInputStream to read data from a file. If we need to perform advanced file operations like memory mapping or random access, we can obtain a FileChannel instance by calling getChannel() on a FileInputStream.

• A channel obtained from the getChannel() method of the Java.oi.FileInputStream instance will be open for reading.
• getChannel() will return the FileChannel object that is associated with this FileInputStream instance.
• The channel position will change whenever we read bytes from this stream.
• Whenever the channel's position is changed, the stream's file position will also get changed.
• The number of bytes read from the file will determine the initial position of the returned channel.

Syntax:

Parameters:

getChannel() method has no parameter.

Return Type:

getChannel method will return a unique FileChannel object.

Example.

FileInputOutput.java

Output:

Current Size of the file is: 289

FileOutputStream

In Java, the FileOutputStream class does not have a getChannel() method to directly obtain a FileChannel instance FileOutputStream is used for writing data to a file. We can obtain a FileChannel instance for advanced write operations by calling getChannel() on a FileOutputStream.

For example:

Output:

Data written to the file.

RandomAccessFile

The RandomAccessFile class provides both read and write capabilities, making it suitable for random access to a file. We can obtain a FileChannel instance directly from a RandomAccessFile using the getChannel() method.

Here's an example of how to use the getChannel() method with RandomAccessFile:

Output:

Bytes written: 24
Read data: Hello, RandomAccessFile!