Programming Fundamentals/Files/Java
< Programming Fundamentals‎ | Files
files.java
// This program creates a file, adds data to the file, displays the file,// appends more data to the file, displays the file, and then deletes the file.// It will not run if the file already exists.//// References:// https://www.mathsisfun.com/temperature-conversion.html​// https://en.wikibooks.org/wiki/Java_Programming​import java.util.*;class files { public static void main(String[] args) { String FILENAME = "~file.txt"; if​(​fileExists​(​FILENAME​)) { System​.​out​.​println​(​"File already exists.\n"); } else { createFile​(​FILENAME​); readFile(FILENAME); appendFile​(​FILENAME​); readFile(FILENAME); deleteFile​(​FILENAME​); } } private static void createFile(String filename) { try { java.io.File file = new java.io.File(filename); java.io.BufferedWriter writer = new java​.​io​.​BufferedWriter​(​new java​.​io​.​FileWriter​(​file​)); float c; float f; writer.write("C\tF\n"); for(c = 0; c <= 50; c++) { f = c * 9 / 5 + 32; writer.write(c + "\t" + f + "\n"); } writer.close(); } catch​(​java​.​io​.​IOException e) { e.printStackTrace(); } } private static void readFile(String filename) { try { java.io.File file = new java.io.File(filename); java​.​io​.​BufferedReader reader = new java​.​io​.​BufferedReader​(​new java​.​io​.​FileReader​(​file​)); String line; while(true) { line = reader.readLine(); if (line == null) { break; } System​.​out​.​println​(​line​); } reader.close(); System.out.println(""); } catch​(​java​.​io​.​IOException e) { e.printStackTrace(); } } private static void appendFile(String filename) { try { java.io.File file = new java.io.File(filename); java.io.BufferedWriter writer = new java​.​io​.​BufferedWriter​(​new java.io.FileWriter(file, true)); float c; float f; for(c = 51; c <= 100; c++) { f = c * 9 / 5 + 32; writer.write(c + "\t" + f + "\n"); } writer.close(); } catch​(​java​.​io​.​IOException e) { e.printStackTrace(); } } private static void deleteFile(String filename) { java.io.File file; file = new java.io.File(filename); file.delete(); } private static boolean fileExists(String filename) { java.io.File file; file = new java.io.File(filename); return file.exists(); }}
Try It
Copy and paste the code above into one of the following free online development environments or use your own Java compiler / interpreter / IDE.
See Also
Wikibooks: Java Programming
← C Sharp
Programming Fundamentals/Files
Lua →
Last edited on 19 April 2020, at 14:43
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