Object Oriented Programming Final File IO

From Dr. Pittman Lecture Slides

File

A collection of 1s and 0s stored on a computer

Absolute File Path

Exact path to a file starting at the root of the file system

Relative File Path

Path to a file relative to the working directory

Aspects of Absolute File Path

Gives name of each folder that needs to be opened. Very tedious and are computer specific

Aspects of Relative File Path

Most programs use this sine it allows for the paths to be more flexible and run on multiple systems

to go down a tree

..

to go up the tree one folder

.

denotes the current directory/folder

File Class

getAbsolutePath()

canWrite()

canRead()

length()

exists()

FileInputStream Class

used to read raw bytes of data from a file; works for any type of file

FileReader

Reads unicode values from the text files; works well to store text data

Input Streams

FileInputStream

FileReader

Read method returns 1 at the end of stream

Scanner Class

Scanner scnr = new Scanner(medicalData);

String id = scnr.next(); (gets next char)

int weight = scnr.nextInt(); (gets next int)

double temperature = scnr.nextDouble(); (gets next double

File Output

FileOutputStream

FileWriter

FileOutputStream Class

FileOutputStream.write(72);

Used to write raw byte data to a file, and can be used to create files of any type

FileWriter Class

FileWriter.write(“H”);

Used to write text data to a file

PrintWriter Class

printWriter.println(“Hello”);

Can be used to wrap an output stream

Gives access to methods normally used for printing to console.

Buffers

allows for data stored in a cache until a certain threshold is reached.

Read Buffer

When empty makes a request to fill in the buffer with data from the designated file

Write Buffer

When full makes a request to write the data to the designated file.

.flush()

force any data currently held in a temporary buffer to be immediately written or transmitted to its final destination