public class SomeIOUtils extends Object
General IO stream manipulation utilities.
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.
Modifier and Type | Field and Description |
---|---|
private static int |
DEFAULT_BUFFER_SIZE
The default buffer size to use for
copyLarge(InputStream, OutputStream) and
copyLarge(Reader, Writer) |
static char |
DIR_SEPARATOR
The system directory separator character.
|
static char |
DIR_SEPARATOR_UNIX
The Unix directory separator character.
|
static char |
DIR_SEPARATOR_WINDOWS
The Windows directory separator character.
|
static String |
LINE_SEPARATOR_UNIX
The Unix line separator string.
|
static String |
LINE_SEPARATOR_WINDOWS
The Windows line separator string.
|
private static int |
SKIP_BUFFER_SIZE
The default buffer size to use for the skip() methods.
|
private static byte[] |
SKIP_BYTE_BUFFER |
private static char[] |
SKIP_CHAR_BUFFER |
Constructor and Description |
---|
SomeIOUtils()
Instances should NOT be constructed in standard programming.
|
Modifier and Type | Method and Description |
---|---|
static void |
closeQuietly(Closeable closeable)
Unconditionally close a
Closeable . |
static void |
closeQuietly(InputStream input)
Unconditionally close an
InputStream . |
static void |
closeQuietly(OutputStream output)
Unconditionally close an
OutputStream . |
static void |
closeQuietly(Reader input)
Unconditionally close an
Reader . |
static void |
closeQuietly(Socket sock)
Unconditionally close a
Socket . |
static void |
closeQuietly(Writer output)
Unconditionally close a
Writer . |
static boolean |
contentEquals(InputStream input1,
InputStream input2)
Compare the contents of two Streams to determine if they are equal or not.
|
static boolean |
contentEquals(Reader input1,
Reader input2)
Compare the contents of two Readers to determine if they are equal or not.
|
static int |
copy(InputStream input,
OutputStream output)
Copy bytes from an
InputStream to an OutputStream . |
static void |
copy(InputStream input,
Writer output)
Copy bytes from an
InputStream to chars on a Writer
using the default character encoding of the platform. |
static void |
copy(InputStream input,
Writer output,
String encoding)
Copy bytes from an
InputStream to chars on a Writer
using the specified character encoding. |
static void |
copy(Reader input,
OutputStream output)
Copy chars from a
Reader to bytes on an
OutputStream using the default character encoding of the
platform, and calling flush. |
static void |
copy(Reader input,
OutputStream output,
String encoding)
Copy chars from a
Reader to bytes on an
OutputStream using the specified character encoding, and calling
flush. |
static int |
copy(Reader input,
Writer output)
Copy chars from a
Reader to a Writer . |
static long |
copyLarge(InputStream input,
OutputStream output)
Copy bytes from a large (over 2GB)
InputStream to an
OutputStream . |
static long |
copyLarge(Reader input,
Writer output)
Copy chars from a large (over 2GB)
Reader to a
Writer . |
static List<String> |
readLines(InputStream input)
Get the contents of an
InputStream as a list of Strings, one
entry per line, using the default character encoding of the platform. |
static List<String> |
readLines(InputStream input,
String encoding)
Get the contents of an
InputStream as a list of Strings, one
entry per line, using the specified character encoding. |
static List<String> |
readLines(Reader input)
Get the contents of a
Reader as a list of Strings, one entry per
line. |
static long |
skip(InputStream input,
long toSkip)
Skip bytes from an input byte stream.
|
static long |
skip(Reader input,
long toSkip)
Skip characters from an input character stream.
|
static void |
skipFully(InputStream input,
long toSkip)
Skip the requested number of bytes or fail if there are not enough left.
|
static void |
skipFully(Reader input,
long toSkip)
Skip the requested number of characters or fail if there are not enough left.
|
static byte[] |
toByteArray(InputStream input,
int size)
Get the contents of an
InputStream as a byte[] . |
static byte[] |
toByteArray(InputStream input,
long size)
Get contents of an
InputStream as a byte[] . |
static byte[] |
toByteArray(String input)
Deprecated.
|
static char[] |
toCharArray(InputStream is)
Get the contents of an
InputStream as a character array using
the default character encoding of the platform. |
static char[] |
toCharArray(InputStream is,
String encoding)
Get the contents of an
InputStream as a character array using
the specified character encoding. |
static char[] |
toCharArray(Reader input)
Get the contents of a
Reader as a character array. |
static InputStream |
toInputStream(CharSequence input)
Convert the specified CharSequence to an input stream, encoded as bytes using
the default character encoding of the platform.
|
static InputStream |
toInputStream(CharSequence input,
String encoding)
Convert the specified CharSequence to an input stream, encoded as bytes using
the specified character encoding.
|
static InputStream |
toInputStream(String input)
Convert the specified string to an input stream, encoded as bytes using the
default character encoding of the platform.
|
static InputStream |
toInputStream(String input,
String encoding)
Convert the specified string to an input stream, encoded as bytes using the
specified character encoding.
|
static String |
toString(InputStream input)
Get the contents of an
InputStream as a String
using the default character encoding of the platform. |
static String |
toString(InputStream input,
String encoding)
Get the contents of an
InputStream as a String
using the specified character encoding. |
static String |
toString(Reader input)
Get the contents of a
Reader as a String. |
static void |
write(byte[] data,
OutputStream output)
Writes bytes from a
byte[] to an OutputStream . |
static void |
write(byte[] data,
Writer output)
Writes bytes from a
byte[] to chars on a Writer
using the default character encoding of the platform. |
static void |
write(byte[] data,
Writer output,
String encoding)
Writes bytes from a
byte[] to chars on a Writer
using the specified character encoding. |
static void |
write(char[] data,
OutputStream output)
Writes chars from a
char[] to bytes on an
OutputStream . |
static void |
write(char[] data,
OutputStream output,
String encoding)
Writes chars from a
char[] to bytes on an
OutputStream using the specified character encoding. |
static void |
write(char[] data,
Writer output)
Writes chars from a
char[] to a Writer using the
default character encoding of the platform. |
static void |
write(CharSequence data,
OutputStream output)
Writes chars from a
CharSequence to bytes on an
OutputStream using the default character encoding of the
platform. |
static void |
write(CharSequence data,
OutputStream output,
String encoding)
Writes chars from a
CharSequence to bytes on an
OutputStream using the specified character encoding. |
static void |
write(CharSequence data,
Writer output)
Writes chars from a
CharSequence to a Writer . |
static void |
write(String data,
OutputStream output)
Writes chars from a
String to bytes on an
OutputStream using the default character encoding of the
platform. |
static void |
write(String data,
OutputStream output,
String encoding)
Writes chars from a
String to bytes on an
OutputStream using the specified character encoding. |
static void |
write(String data,
Writer output)
Writes chars from a
String to a Writer . |
public static final char DIR_SEPARATOR_UNIX
public static final char DIR_SEPARATOR_WINDOWS
public static final char DIR_SEPARATOR
public static final String LINE_SEPARATOR_UNIX
public static final String LINE_SEPARATOR_WINDOWS
private static final int DEFAULT_BUFFER_SIZE
copyLarge(InputStream, OutputStream)
and
copyLarge(Reader, Writer)
private static final int SKIP_BUFFER_SIZE
private static char[] SKIP_CHAR_BUFFER
private static byte[] SKIP_BYTE_BUFFER
public SomeIOUtils()
public static void closeQuietly(Reader input)
Reader
.
Equivalent to Reader.close()
, except any exceptions will be ignored.
This is typically used in finally blocks.
Example code:
char[] data = new char[1024]; Reader in = null; try { in = new FileReader("foo.txt"); in.read(data); in.close(); // close errors are handled } catch (Exception e) { // error handling } finally { IOUtils.closeQuietly(in); }
input
- the Reader to close, may be null or already closedpublic static void closeQuietly(Writer output)
Writer
.
Equivalent to Writer.close()
, except any exceptions will be ignored.
This is typically used in finally blocks.
Example code:
Writer out = null; try { out = new StringWriter(); out.write("Hello World"); out.close(); // close errors are handled } catch (Exception e) { // error handling } finally { IOUtils.closeQuietly(out); }
output
- the Writer to close, may be null or already closedpublic static void closeQuietly(InputStream input)
InputStream
.
Equivalent to InputStream.close()
, except any exceptions will be
ignored. This is typically used in finally blocks.
Example code:
byte[] data = new byte[1024]; InputStream in = null; try { in = new FileInputStream("foo.txt"); in.read(data); in.close(); // close errors are handled } catch (Exception e) { // error handling } finally { IOUtils.closeQuietly(in); }
input
- the InputStream to close, may be null or already closedpublic static void closeQuietly(OutputStream output)
OutputStream
.
Equivalent to OutputStream.close()
, except any exceptions will be
ignored. This is typically used in finally blocks.
Example code:
byte[] data = "Hello, World".getBytes(); OutputStream out = null; try { out = new FileOutputStream("foo.txt"); out.write(data); out.close(); // close errors are handled } catch (IOException e) { // error handling } finally { IOUtils.closeQuietly(out); }
output
- the OutputStream to close, may be null or already closedpublic static void closeQuietly(Closeable closeable)
Closeable
.
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); }
closeable
- the object to close, may be null or already closedpublic static void closeQuietly(Socket sock)
Socket
.
Equivalent to Socket.close()
, except any exceptions will be ignored.
This is typically used in finally blocks.
Example code:
Socket socket = null; try { socket = new Socket("http://www.foo.com/", 80); // process socket socket.close(); } catch (Exception e) { // error handling } finally { IOUtils.closeQuietly(socket); }
sock
- the Socket to close, may be null or already closedpublic static byte[] toByteArray(InputStream input, long size) throws IOException
InputStream
as a byte[]
. Use
this method instead of toByteArray(InputStream)
when
InputStream
size is known. NOTE: the method checks that
the length can safely be cast to an int without truncation before using
IOUtils#toByteArray(java.io.InputStream, int)
to read into the byte
array. (Arrays can have no more than Integer.MAX_VALUE entries anyway)input
- the InputStream
to read fromsize
- the size of InputStream
IOException
- if an I/O error occurs or InputStream
size
differ from parameter sizeIllegalArgumentException
- if size is less than zero or size is greater
than Integer.MAX_VALUEIOUtils#toByteArray(java.io.InputStream, int)
public static byte[] toByteArray(InputStream input, int size) throws IOException
InputStream
as a byte[]
. Use
this method instead of toByteArray(InputStream)
when
InputStream
size is knowninput
- the InputStream
to read fromsize
- the size of InputStream
IOException
- if an I/O error occurs or InputStream
size
differ from parameter sizeIllegalArgumentException
- if size is less than zero@Deprecated public static byte[] toByteArray(String input) throws IOException
String.getBytes()
String
as a byte[]
using the
default character encoding of the platform.
This is the same as String.getBytes()
.
input
- the String
to convertNullPointerException
- if the input is nullIOException
- if an I/O error occurs (never occurs)public static char[] toCharArray(InputStream is) throws IOException
InputStream
as a character array using
the default character encoding of the platform.
This method buffers the input internally, so there is no need to use a
BufferedInputStream
.
is
- the InputStream
to read fromNullPointerException
- if the input is nullIOException
- if an I/O error occurspublic static char[] toCharArray(InputStream is, String encoding) throws IOException
InputStream
as a character array using
the specified character encoding.
Character encoding names can be found at IANA.
This method buffers the input internally, so there is no need to use a
BufferedInputStream
.
is
- the InputStream
to read fromencoding
- the encoding to use, null means platform defaultNullPointerException
- if the input is nullIOException
- if an I/O error occurspublic static char[] toCharArray(Reader input) throws IOException
Reader
as a character array.
This method buffers the input internally, so there is no need to use a
BufferedReader
.
input
- the Reader
to read fromNullPointerException
- if the input is nullIOException
- if an I/O error occurspublic static String toString(InputStream input) throws IOException
InputStream
as a String
using the default character encoding of the platform.
This method buffers the input internally, so there is no need to use a
BufferedInputStream
.
input
- the InputStream
to read fromNullPointerException
- if the input is nullIOException
- if an I/O error occurspublic static String toString(InputStream input, String encoding) throws IOException
InputStream
as a String
using the specified character encoding.
Character encoding names can be found at IANA.
This method buffers the input internally, so there is no need to use a
BufferedInputStream
.
input
- the InputStream
to read fromencoding
- the encoding to use, null means platform defaultNullPointerException
- if the input is nullIOException
- if an I/O error occurspublic static String toString(Reader input) throws IOException
Reader
as a String.
This method buffers the input internally, so there is no need to use a
BufferedReader
.
input
- the Reader
to read fromNullPointerException
- if the input is nullIOException
- if an I/O error occurspublic static List<String> readLines(InputStream input) throws IOException
InputStream
as a list of Strings, one
entry per line, using the default character encoding of the platform.
This method buffers the input internally, so there is no need to use a
BufferedInputStream
.
input
- the InputStream
to read from, not nullNullPointerException
- if the input is nullIOException
- if an I/O error occurspublic static List<String> readLines(InputStream input, String encoding) throws IOException
InputStream
as a list of Strings, one
entry per line, using the specified character encoding.
Character encoding names can be found at IANA.
This method buffers the input internally, so there is no need to use a
BufferedInputStream
.
input
- the InputStream
to read from, not nullencoding
- the encoding to use, null means platform defaultNullPointerException
- if the input is nullIOException
- if an I/O error occurspublic static List<String> readLines(Reader input) throws IOException
Reader
as a list of Strings, one entry per
line.
This method buffers the input internally, so there is no need to use a
BufferedReader
.
input
- the Reader
to read from, not nullNullPointerException
- if the input is nullIOException
- if an I/O error occurspublic static InputStream toInputStream(CharSequence input)
input
- the CharSequence to convertpublic static InputStream toInputStream(CharSequence input, String encoding) throws IOException
Character encoding names can be found at IANA.
input
- the CharSequence to convertencoding
- the encoding to use, null means platform defaultIOException
- if the encoding is invalidpublic static InputStream toInputStream(String input)
input
- the string to convertpublic static InputStream toInputStream(String input, String encoding) throws IOException
Character encoding names can be found at IANA.
input
- the string to convertencoding
- the encoding to use, null means platform defaultIOException
- if the encoding is invalidpublic static void write(byte[] data, OutputStream output) throws IOException
byte[]
to an OutputStream
.data
- the byte array to write, do not modify during output, null ignoredoutput
- the OutputStream
to write toNullPointerException
- if output is nullIOException
- if an I/O error occurspublic static void write(byte[] data, Writer output) throws IOException
byte[]
to chars on a Writer
using the default character encoding of the platform.
This method uses String.String(byte[])
.
data
- the byte array to write, do not modify during output, null ignoredoutput
- the Writer
to write toNullPointerException
- if output is nullIOException
- if an I/O error occurspublic static void write(byte[] data, Writer output, String encoding) throws IOException
byte[]
to chars on a Writer
using the specified character encoding.
Character encoding names can be found at IANA.
This method uses String.String(byte[], String)
.
data
- the byte array to write, do not modify during output, null ignoredoutput
- the Writer
to write toencoding
- the encoding to use, null means platform defaultNullPointerException
- if output is nullIOException
- if an I/O error occurspublic static void write(char[] data, Writer output) throws IOException
char[]
to a Writer
using the
default character encoding of the platform.data
- the char array to write, do not modify during output, null ignoredoutput
- the Writer
to write toNullPointerException
- if output is nullIOException
- if an I/O error occurspublic static void write(char[] data, OutputStream output) throws IOException
char[]
to bytes on an
OutputStream
.
This method uses String.String(char[])
and String.getBytes()
.
data
- the char array to write, do not modify during output, null ignoredoutput
- the OutputStream
to write toNullPointerException
- if output is nullIOException
- if an I/O error occurspublic static void write(char[] data, OutputStream output, String encoding) throws IOException
char[]
to bytes on an
OutputStream
using the specified character encoding.
Character encoding names can be found at IANA.
This method uses String.String(char[])
and
String.getBytes(String)
.
data
- the char array to write, do not modify during output, null ignoredoutput
- the OutputStream
to write toencoding
- the encoding to use, null means platform defaultNullPointerException
- if output is nullIOException
- if an I/O error occurspublic static void write(CharSequence data, Writer output) throws IOException
CharSequence
to a Writer
.data
- the CharSequence
to write, null ignoredoutput
- the Writer
to write toNullPointerException
- if output is nullIOException
- if an I/O error occurspublic static void write(CharSequence data, OutputStream output) throws IOException
CharSequence
to bytes on an
OutputStream
using the default character encoding of the
platform.
This method uses String.getBytes()
.
data
- the CharSequence
to write, null ignoredoutput
- the OutputStream
to write toNullPointerException
- if output is nullIOException
- if an I/O error occurspublic static void write(CharSequence data, OutputStream output, String encoding) throws IOException
CharSequence
to bytes on an
OutputStream
using the specified character encoding.
Character encoding names can be found at IANA.
This method uses String.getBytes(String)
.
data
- the CharSequence
to write, null ignoredoutput
- the OutputStream
to write toencoding
- the encoding to use, null means platform defaultNullPointerException
- if output is nullIOException
- if an I/O error occurspublic static void write(String data, Writer output) throws IOException
String
to a Writer
.data
- the String
to write, null ignoredoutput
- the Writer
to write toNullPointerException
- if output is nullIOException
- if an I/O error occurspublic static void write(String data, OutputStream output) throws IOException
String
to bytes on an
OutputStream
using the default character encoding of the
platform.
This method uses String.getBytes()
.
data
- the String
to write, null ignoredoutput
- the OutputStream
to write toNullPointerException
- if output is nullIOException
- if an I/O error occurspublic static void write(String data, OutputStream output, String encoding) throws IOException
String
to bytes on an
OutputStream
using the specified character encoding.
Character encoding names can be found at IANA.
This method uses String.getBytes(String)
.
data
- the String
to write, null ignoredoutput
- the OutputStream
to write toencoding
- the encoding to use, null means platform defaultNullPointerException
- if output is nullIOException
- if an I/O error occurspublic static int copy(InputStream input, OutputStream output) throws 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 toNullPointerException
- if the input or output is nullIOException
- if an I/O error occurspublic static long copyLarge(InputStream input, OutputStream output) throws IOException
InputStream
to an
OutputStream
.
This method buffers the input internally, so there is no need to use a
BufferedInputStream
.
input
- the InputStream
to read fromoutput
- the OutputStream
to write toNullPointerException
- if the input or output is nullIOException
- if an I/O error occurspublic static void copy(InputStream input, Writer output) throws IOException
InputStream
to chars on a Writer
using the default character encoding of the platform.
This method buffers the input internally, so there is no need to use a
BufferedInputStream
.
This method uses InputStreamReader
.
input
- the InputStream
to read fromoutput
- the Writer
to write toNullPointerException
- if the input or output is nullIOException
- if an I/O error occurspublic static void copy(InputStream input, Writer output, String encoding) throws IOException
InputStream
to chars on a Writer
using the specified character encoding.
This method buffers the input internally, so there is no need to use a
BufferedInputStream
.
Character encoding names can be found at IANA.
This method uses InputStreamReader
.
input
- the InputStream
to read fromoutput
- the Writer
to write toencoding
- the encoding to use, null means platform defaultNullPointerException
- if the input or output is nullIOException
- if an I/O error occurspublic static int copy(Reader input, Writer output) throws IOException
Reader
to a Writer
.
This method buffers the input internally, so there is no need to use a
BufferedReader
.
Large streams (over 2GB) will return a chars copied value of -1
after the copy has completed since the correct number of chars cannot be
returned as an int. For large streams use the
copyLarge(Reader, Writer)
method.
input
- the Reader
to read fromoutput
- the Writer
to write toNullPointerException
- if the input or output is nullIOException
- if an I/O error occurspublic static long copyLarge(Reader input, Writer output) throws IOException
Reader
to a
Writer
.
This method buffers the input internally, so there is no need to use a
BufferedReader
.
input
- the Reader
to read fromoutput
- the Writer
to write toNullPointerException
- if the input or output is nullIOException
- if an I/O error occurspublic static void copy(Reader input, OutputStream output) throws IOException
Reader
to bytes on an
OutputStream
using the default character encoding of the
platform, and calling flush.
This method buffers the input internally, so there is no need to use a
BufferedReader
.
Due to the implementation of OutputStreamWriter, this method performs a flush.
This method uses OutputStreamWriter
.
input
- the Reader
to read fromoutput
- the OutputStream
to write toNullPointerException
- if the input or output is nullIOException
- if an I/O error occurspublic static void copy(Reader input, OutputStream output, String encoding) throws IOException
Reader
to bytes on an
OutputStream
using the specified character encoding, and calling
flush.
This method buffers the input internally, so there is no need to use a
BufferedReader
.
Character encoding names can be found at IANA.
Due to the implementation of OutputStreamWriter, this method performs a flush.
This method uses OutputStreamWriter
.
input
- the Reader
to read fromoutput
- the OutputStream
to write toencoding
- the encoding to use, null means platform defaultNullPointerException
- if the input or output is nullIOException
- if an I/O error occurspublic static boolean contentEquals(InputStream input1, InputStream input2) throws IOException
This method buffers the input internally using
BufferedInputStream
if they are not already buffered.
input1
- the first streaminput2
- the second streamNullPointerException
- if either input is nullIOException
- if an I/O error occurspublic static boolean contentEquals(Reader input1, Reader input2) throws IOException
This method buffers the input internally using BufferedReader
if
they are not already buffered.
input1
- the first readerinput2
- the second readerNullPointerException
- if either input is nullIOException
- if an I/O error occurspublic static long skip(InputStream input, long toSkip) throws IOException
Reader
.input
- byte stream to skiptoSkip
- number of bytes to skip.IOException
- if there is a problem reading the fileIllegalArgumentException
- if toSkip is negativeInputStream.skip(long)
public static long skip(Reader input, long toSkip) throws IOException
Reader
.input
- character stream to skiptoSkip
- number of characters to skip.IOException
- if there is a problem reading the fileIllegalArgumentException
- if toSkip is negativeReader.skip(long)
public static void skipFully(InputStream input, long toSkip) throws IOException
This allows for the possibility that InputStream.skip(long)
may not
skip as many bytes as requested (most likely because of reaching EOF).
input
- stream to skiptoSkip
- the number of bytes to skipIOException
- if there is a problem reading the fileIllegalArgumentException
- if toSkip is negativeEOFException
- if the number of bytes skipped was incorrectInputStream.skip(long)
public static void skipFully(Reader input, long toSkip) throws IOException
This allows for the possibility that Reader.skip(long)
may not skip
as many characters as requested (most likely because of reaching EOF).
input
- stream to skiptoSkip
- the number of characters to skipIOException
- if there is a problem reading the fileIllegalArgumentException
- if toSkip is negativeEOFException
- if the number of characters skipped was incorrectReader.skip(long)
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