System Methods | |
Some System methods are relevant to I/O | |
String System.getProperty("user.dir") | Returns the path to the current directory (ie, the value of "."). |
i
and j
are int,
s
and t
are Strings,
and c
is a char.
boolean | f.exists() | true if file exists. |
boolean | f.isFile() | true if its a file. |
boolean | f.isDirectory() | true if its a directory. |
String | f.getName() | returns name of file/directory. |
String | f.getPath() | returns path of file/directory. |
File[] | File.listRoots() | [Java 2] list of file system roots, eg, A:, C:, .... |
Constructors -- see example below | ||
BufferedReader Methods | ||
String | br.readLine() | Returns next input line without newline char(s) or null if no more input. May throw IOException. |
String | br.close() | Should close when finished reading. |
BufferedWriter Methods | ||
void | bw.writeLine(s) | Writes s to file without newline char(s). May throw IOException. |
String | bw.close() | MUST close when finished writing. |
// Example reads from from one file and writes to another. // Assume inFile and outFile are Strings with path/file names. try { BufferedReader bufReader = new BufferedReader(new FileReader(inFile)); BufferedWriter bufWriter = new BufferedWriter(new FileWriter(outFile)); String line = null; while ((line=bufReader.readLine()) != null){ bufWriter.write(line); bufWriter.newLine(); // adds newline character(s) } bufReader.close(); bufWriter.close(); } catch (IOException e) { System.err.println(e); System.exit(1); }