Java file input stream

I write about modern JavaScript, Node. The newsletter is sent every week and includes early access to clear, concise, and easy-to-follow tutorials, and other stuff I think you'd enjoy! No spam ever, unsubscribe at any time. How to read a file using FileInputStream in Java. Skip to content. Change Language. Related Articles. Table of Contents. Improve Article. Save Article. Like Article. FileInputStream package. The FileInputStream class is used to reads the streams of raw bytes byte by byte like an image data video, audio, etc.

This function is used to read bytes of data from the input stream up to specified len into destination b array at start offset. This function is used to return the estimated number of bytes that can be read from the input stream. Next, we write the java code to understand the FileInputStream class more clearly with the following example where we create a FileInputStream object by using the FileInputStream class constructor and pass the file name to read a character, as below —.

Next, we write the java code to understand the FileInputStream class more clearly; we create an FileInputStream object to read all characters from the file, as below:. Throws: FileNotFoundException - if the file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading. SecurityException - if a security manager exists and its checkRead method denies read access to the file. See Also: SecurityManager.

First, if there is a security manager, its checkRead method is called with the path represented by the file argument as its argument. Parameters: file - the file to be opened for reading.

See Also: File. If there is a security manager, its checkRead method is called with the file descriptor fdObj as its argument to see if it's ok to read the file descriptor. If read access is denied to the file descriptor a SecurityException is thrown. If fdObj is null then a NullPointerException is thrown. This constructor does not throw an exception if fdObj is invalid. Parameters: fdObj - the file descriptor to be opened for reading.

Throws: SecurityException - if a security manager exists and its checkRead method denies read access to the file descriptor. This method blocks if no input is yet available. Specified by: read in class InputStream Returns: the next byte of data, or -1 if the end of the file is reached.

This method blocks until some input is available. Overrides: read in class InputStream Parameters: b - the buffer into which the data is read. Returns: the total number of bytes read into the buffer, or -1 if there is no more data because the end of the file has been reached.