home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Chip 2005 February
/
CMCD0205.ISO
/
Software
/
Freeware
/
Programare
/
bluej
/
bluejsetup-203.exe
/
{app}
/
examples
/
file-reader
/
FileReader.java
< prev
next >
Wrap
Text File
|
2004-12-19
|
3KB
|
90 lines
import java.io.*;
import java.net.URL;
/**
* This is a little demo showing how to read text files. It will find files
* that are situated anywhere in the classpath.
*
* Currently, two demo methods are available. Both simply print a text file to the
* terminal. One returns exceptions in case of a problem, the other prints out
* error messages.
*
* @author Michael KÜlling
* @version 1.0 (19. Feb 2002)
*/
public class FileReader
{
/**
* Create a file reader
*/
public FileReader()
{
// nothing to do...
}
/**
* Show the contents of the file 'fileName' on standard out (the text terminal).
*
* @param fileName The name of the file to show
* @throws IOException if the file could not be opened
*/
public void showFile(String fileName)
throws IOException
{
InputStream fstream = openFile(fileName);
// wrap the stream into an InputStreamReader, so that we read characters
// rather than bytes (important for non-ascii characters); then wrap it into
// a BufferedReader, so that we can read lines, rather than single characters
BufferedReader in = new BufferedReader(new InputStreamReader(fstream));
// okay, we're ready to go...
System.out.println("File: " + fileName);
String line = in.readLine();
while(line != null) {
System.out.println(line);
line = in.readLine();
}
System.out.println("<end of file>");
}
/**
* Same as 'showfile', but don't throw exceptions. If an error occurs,
* write an error message to the terminal.
*
* @param fileName The name of the file to show
*/
public void checkedShowFile(String fileName)
{
try {
showFile(fileName);
}
catch(IOException exc) {
System.out.println("There was a problem showing this file.");
System.out.println("The error encountered is:");
System.out.println(exc);
}
}
/**
* Open a text file and return a stream to read from that file.
* The file can reside anywhere in the classpath.
*
* @param fileName The name of the file to open
* @return An open stream to read from the file
* @throws IOException if the file could not be opened
*/
public InputStream openFile(String fileName)
throws IOException
{
if(fileName == null)
throw new IOException("Cannot open file - filename was null.");
URL url = getClass().getClassLoader().getResource(fileName);
if(url == null)
throw new IOException("File not found: " + fileName);
return url.openStream();
}
}