Try the modified code below, it should help to have a better output : no
blank,
no empty line and should be valid on the 3 systems: linux, win and mac.
Cheers,
Xavier.
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;
/**
* An OutputStream that flushes out to a Category.<p>
* <p/>
* Note that no data is written out to the Category until the stream is
* flushed or closed.<p>
* <p/>
* Example:<pre>
* // make sure everything sent to System.err is logged
* System.setErr(new PrintStream(new
* JscLoggingOutputStream(Category.getRoot(),
* Priority.WARN), true));
* <p/>
* // make sure everything sent to System.out is also logged
* System.setOut(new PrintStream(new
* JscLoggingOutputStream(Category.getRoot(),
* Priority.INFO), true));
* </pre>
*
* @author <a href="mailto://[EMAIL PROTECTED]">Jim Moore</a>
* @see Category
*/
//
public class JscLoggingOutputStream extends OutputStream {
static Logger myLogger =
Logger.getLogger(JscLoggingOutputStream.class.getName());
/**
* Used to maintain the contract of [EMAIL PROTECTED] #close()}.
*/
protected boolean hasBeenClosed = false;
/**
* The internal buffer where data is stored.
*/
protected byte[] buf;
/**
* The number of valid bytes in the buffer. This value is always
* in the range <tt>0</tt> through <tt>buf.length</tt>; elements
* <tt>buf[0]</tt> through <tt>buf[count-1]</tt> contain valid
* byte data.
*/
protected int count;
/**
* Remembers the size of the buffer for speed.
*/
private int bufLength;
/**
* The default number of bytes in the buffer. =2048
*/
public static final int DEFAULT_BUFFER_LENGTH = 2048;
/**
* The category to write to.
*/
protected Logger logger;
/**
* The priority to use when writing to the Category.
*/
protected Level level;
private JscLoggingOutputStream() {
// illegal
}
/**
* Creates the JscLoggingOutputStream to flush to the given Category.
*
* @param log the Logger to write to
* @param level the Level to use when writing to the Logger
* @throws IllegalArgumentException if cat == null or priority ==
* null
*/
public JscLoggingOutputStream(Logger log, Level level)
throws IllegalArgumentException {
if (log == null) {
throw new IllegalArgumentException("cat == null");
}
if (level == null) {
throw new IllegalArgumentException("priority == null");
}
this.level = level;
logger = log;
bufLength = DEFAULT_BUFFER_LENGTH;
buf = new byte[DEFAULT_BUFFER_LENGTH];
count = 0;
}
/**
* Closes this output stream and releases any system resources
* associated with this stream. The general contract of
* <code>close</code>
* is that it closes the output stream. A closed stream cannot
* perform
* output operations and cannot be reopened.
*/
public void close() {
flush();
hasBeenClosed = true;
}
/**
* Writes the specified byte to this output stream. The general
* contract for <code>write</code> is that one byte is written
* to the output stream. The byte to be written is the eight
* low-order bits of the argument <code>b</code>. The 24
* high-order bits of <code>b</code> are ignored.
*
* @param b the <code>byte</code> to write
* @throws IOException if an I/O error occurs. In particular,
* an <code>IOException</code> may be thrown if
* the
* output stream has been closed.
*/
public void write(final int b) throws IOException {
if (hasBeenClosed) {
throw new IOException("The stream has been closed.");
}
// would this be writing past the buffer?
if (count == bufLength) {
// grow the buffer
final int newBufLength = bufLength + DEFAULT_BUFFER_LENGTH;
final byte[] newBuf = new byte[newBufLength];
System.arraycopy(buf, 0, newBuf, 0, bufLength);
buf = newBuf;
bufLength = newBufLength;
}
buf[count] = (byte) b;
count++;
}
/**
* Flushes this output stream and forces any buffered output bytes
* to be written out. The general contract of <code>flush</code> is
* that calling it is an indication that, if any bytes previously
* written have been buffered by the implementation of the output
* stream, such bytes should immediately be written to their
* intended destination.
*/
public void flush() {
if (count == 0) {
return;
}
// don't print out blank lines; flushing from PrintStream puts
// out these
// For linux system
if (count == 1 && ((char) buf[0]) == '\n') {
reset();
return;
}
// For mac system
if (count == 1 && ((char) buf[0]) == '\r') {
reset();
return;
}
// On windows system
if (count==2 && (char)buf[0]=='\r' && (char)buf[1]=='\n') {
reset();
return;
}
final byte[] theBytes = new byte[count];
System.arraycopy(buf, 0, theBytes, 0, count);
logger.log(level, new String(theBytes));
reset();
}
private void reset() {
// not resetting the buffer -- assuming that if it grew then it
// will likely grow similarly again
count = 0;
}
}
Henrik Engert wrote:
Hi,
This subject has been upp before, but I can not get it to work in our
app. We need/want to make sure that runtime exceptions such as
NullPointerException etc. should be logged together in our log file that
is managed by log4j. I have found some old emails on this mailing list
where the suggestion was to write your own Outputstream to get it to
work. I have tried to use that code, but we get a bunch of
space-characters in our logfile.
Is there any easier way in redirecting System.err to log4j?
Any suggestion would help.
Code below.
Thanks.
************************
import java.io.*;
import org.apache.log4j.*;
/**
* An OutputStream that flushes out to a Category.<p>
* <p/>
* Note that no data is written out to the Category until the stream is
* flushed or closed.<p>
* <p/>
* Example:<pre>
* // make sure everything sent to System.err is logged
* System.setErr(new PrintStream(new
LoggingOutputStream(Category.getRoot(),
* Priority.WARN), true));
* <p/>
* // make sure everything sent to System.out is also logged
* System.setOut(new PrintStream(new
LoggingOutputStream(Category.getRoot(),
* Priority.INFO), true));
* </pre>
*
* @author <a href="mailto://[EMAIL PROTECTED]">Jim Moore</a>
* @see Category
*/
public class LoggingOutputStream extends OutputStream {
/**
* Used to maintain the contract of [EMAIL PROTECTED] #close()}.
*/
protected boolean hasBeenClosed = false;
/**
* The internal buffer where data is stored.
*/
protected byte[] buf;
/**
* The number of valid bytes in the buffer. This value is always
* in the range <tt>0</tt> through <tt>buf.length</tt>; elements
* <tt>buf[0]</tt> through <tt>buf[count-1]</tt> contain valid
* byte data.
*/
protected int count;
/**
* Remembers the size of the buffer for speed.
*/
private int bufLength;
/**
* The default number of bytes in the buffer. =2048
*/
public static final int DEFAULT_BUFFER_LENGTH = 2048;
/**
* The category to write to.
*/
protected Logger logger;
/**
* The priority to use when writing to the Category.
*/
protected Level level;
private LoggingOutputStream() {
// illegal
}
/**
* Creates the LoggingOutputStream to flush to the given Category.
*
* @param log the Logger to write to
* @param level the Level to use when writing to the Logger
* @throws IllegalArgumentException if cat == null or priority ==
null
*/
public LoggingOutputStream(Logger log, Level level)
throws IllegalArgumentException {
if (log == null) {
throw new IllegalArgumentException("cat == null");
}
if (level == null) {
throw new IllegalArgumentException("priority == null");
}
this.level = level;
logger = log;
bufLength = DEFAULT_BUFFER_LENGTH;
buf = new byte[DEFAULT_BUFFER_LENGTH];
count = 0;
}
/**
* Closes this output stream and releases any system resources
* associated with this stream. The general contract of
* <code>close</code>
* is that it closes the output stream. A closed stream cannot
perform
* output operations and cannot be reopened.
*/
public void close() {
flush();
hasBeenClosed = true;
}
/**
* Writes the specified byte to this output stream. The general
* contract for <code>write</code> is that one byte is written
* to the output stream. The byte to be written is the eight
* low-order bits of the argument <code>b</code>. The 24
* high-order bits of <code>b</code> are ignored.
*
* @param b the <code>byte</code> to write
* @throws IOException if an I/O error occurs. In particular,
* an <code>IOException</code> may be thrown if
the
* output stream has been closed.
*/
public void write(final int b) throws IOException {
if (hasBeenClosed) {
throw new IOException("The stream has been closed.");
}
// would this be writing past the buffer?
if (count == bufLength) {
// grow the buffer
final int newBufLength = bufLength + DEFAULT_BUFFER_LENGTH;
final byte[] newBuf = new byte[newBufLength];
System.arraycopy(buf, 0, newBuf, 0, bufLength);
buf = newBuf;
bufLength = newBufLength;
}
buf[count] = (byte) b;
count++;
}
/**
* Flushes this output stream and forces any buffered output bytes
* to be written out. The general contract of <code>flush</code> is
* that calling it is an indication that, if any bytes previously
* written have been buffered by the implementation of the output
* stream, such bytes should immediately be written to their
* intended destination.
*/
public void flush() {
if (count == 0) {
return;
}
// don't print out blank lines; flushing from PrintStream puts
out these
if (count == 1 && ((char) buf[0]) == '\n') {
reset();
return;
}
final byte[] theBytes = new byte[buf.length];
System.arraycopy(buf, 0, theBytes, 0, count);
logger.log(level, new String(theBytes));
reset();
}
private void reset() {
// not resetting the buffer -- assuming that if it grew then it
// will likely grow similarly again
count = 0;
}
}
************************
************************
// remember STDERR
PrintStream se = System.err;
// make sure everything sent to System.err is logged
System.setErr(new PrintStream(new
LoggingOutputStream(Logger.getRootLogger(),
Level.WARN), true));
// make sure everything sent to System.out is also logged
System.setOut(new PrintStream(new
LoggingOutputStream(Logger.getRootLogger(),
Level.INFO), true));
***********************
###########################################
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