public class IOUtils
extends java.lang.Object
This class provides static utility methods for input/output operations.
The byte-to-char methods and char-to-byte methods involve a conversion step. Two methods are provided in each case, one that uses the platform default encoding and the other which allows you to specify an encoding. You are encouraged to always specify an encoding because relying on the platform default can lead to unexpected results, for example when moving from development to production.
All the methods in this class that read a stream are buffered internally.
This means that there is no cause to use a BufferedInputStream
or BufferedReader. The default buffer size of 4K has been shown
to be efficient in tests.
Wherever possible, the methods in this class do not flush or close the stream. This is to avoid making non-portable assumptions about the streams' origin and further use. Thus the caller is still responsible for closing streams after use.
Origin of code: Excalibur.
| Constructor and Description |
|---|
IOUtils()
Instances should NOT be constructed in standard programming.
|
| Modifier and Type | Method and Description |
|---|---|
static void |
closeQuietly(java.io.Closeable closeable)
Closes a
Closeable unconditionally. |
static int |
copy(java.io.InputStream input,
java.io.OutputStream output)
Copy bytes from an
InputStream to an
OutputStream. |
static long |
copyLarge(java.io.InputStream input,
java.io.OutputStream output)
Copy bytes from a large (over 2GB)
InputStream to an
OutputStream. |
public IOUtils()
public static void closeQuietly(java.io.Closeable closeable)
Closeable unconditionally.
Equivalent to Closeable.close(), except any exceptions will be ignored. This is typically used in
finally blocks.
Example code:
Closeable closeable = null;
try {
closeable = new FileReader("foo.txt");
// process closeable
closeable.close();
} catch (Exception e) {
// error handling
} finally {
IOUtils.closeQuietly(closeable);
}
Closing all streams:
try {
return IOUtils.copy(inputStream, outputStream);
} finally {
IOUtils.closeQuietly(inputStream);
IOUtils.closeQuietly(outputStream);
}
closeable - the objects to close, may be null or already closedpublic static int copy(java.io.InputStream input,
java.io.OutputStream output)
throws java.io.IOException
InputStream to an
OutputStream.
This method buffers the input internally, so there is no need to use a
BufferedInputStream.
Large streams (over 2GB) will return a bytes copied value of
-1 after the copy has completed since the correct
number of bytes cannot be returned as an int. For large streams
use the copyLarge(InputStream, OutputStream) method.
input - the InputStream to read fromoutput - the OutputStream to write tojava.lang.NullPointerException - if the input or output is nulljava.io.IOException - if an I/O error occurspublic static long copyLarge(java.io.InputStream input,
java.io.OutputStream output)
throws java.io.IOException
InputStream to an
OutputStream.
This method buffers the input internally, so there is no need to use a
BufferedInputStream.
The buffer size is given by DEFAULT_BUFFER_SIZE.
input - the InputStream to read fromoutput - the OutputStream to write tojava.lang.NullPointerException - if the input or output is nulljava.io.IOException - if an I/O error occursCopyright © 2000-2015 Apache Software Foundation. All Rights Reserved.