Java Console and File Input/Ouptut Cheat Sheet

Console Output

System.out.print("Hello ");
System.out.println("world");

Console Input

BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
String text = in.readLine();

File Output

File dstFile = new File("K:\\location\\outputfile.txt");
PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(dstFile)));
out.print("Hello ");
out.println("world");
out.close();

File Input

File srcFile = new File("K:\\location\\inputfile.txt");
BufferedReader in = new BufferedReader(new FileReader(srcFile));
String text = in.readLine();
in.close();

Converting input data

String text = in.readLine();
int x = Integer.parseInt(text);
double y = Double.parseDouble(text);

Reading until EOF

while (in.ready()) {
text = in.readLine();
System.out.println(text);
}

Pulling apart delimited items on a line

String text = "Beggars in Spain*Nancy Kress*1992";
StringTokenizer tokenizer = new StringTokenizer(text,"*");
String title = tokenizer.nextToken();
String author = tokenizer.nextToken();
String year = tokenizer.nextToken();

String letters = "a b c d e f g h i j";
StringTokenizer tokenizer = new StringTokenizer(text," ");
String allText[] = new String[10];
int pos = 0;
while (tokenizer.hasMoreTokens())
allText[pos++] = tokenizer.nextToken();