Class IOUtil
- java.lang.Object
-
- org.apache.maven.shared.utils.io.IOUtil
-
public final class IOUtil extends java.lang.Object
General IO Stream manipulation.
This class provides static utility methods for input/output operations, particularly buffered copying between sources (
InputStream
,Reader
,String
andbyte[]
) and destinations (OutputStream
,Writer
,String
andbyte[]
).Unless otherwise noted, these
copy
methods do not flush or close the streams. Often, doing so would require making non-portable assumptions about the streams' origin and further use. This means that both streams'close()
methods must be called after copying. if one omits this step, then the stream resources (sockets, file descriptors) are released when the associated Stream is garbage-collected. It is not a good idea to rely on this mechanism.For each
copy
method, a variant is provided that allows the caller to specify the buffer size (the default is 4k). As the buffer size can have a fairly large impact on speed, this may be worth tweaking. Often "large buffer -> faster" does not hold, even for large data transfers.For byte-to-char methods, a
copy
variant allows the encoding to be selected (otherwise the platform default is used).The
copy
methods use an internal buffer when copying. It is therefore advisable not to deliberately wrap the stream arguments to thecopy
methods inBuffered*
streams. For example, don't do the following:copy( new BufferedInputStream( in ), new BufferedOutputStream( out ) );
The rationale is as follows:
Imagine that an InputStream's read() is a very expensive operation, which would usually suggest wrapping in a BufferedInputStream. The BufferedInputStream works by issuing infrequent
InputStream.read(byte[] b, int off, int len)
requests on the underlying InputStream, to fill an internal buffer, from which furtherread
requests can inexpensively get their data (until the buffer runs out).However, the
copy
methods do the same thing, keeping an internal buffer, populated byInputStream.read(byte[] b, int off, int len)
requests. Having two buffers (or three if the destination stream is also buffered) is pointless, and the unnecessary buffer management hurts performance slightly (about 3%, according to some simple experiments).- Version:
- CVS $Revision$ $Date$
- Author:
- Peter Donald, Jeff Turner
-
-
Method Summary
All Methods Static Methods Concrete Methods Deprecated Methods Modifier and Type Method Description static void
close(java.io.InputStream inputStream)
Deprecated.use try-with-resourcesstatic void
close(java.io.OutputStream outputStream)
Deprecated.use try-with-resourcesstatic void
close(java.io.Reader reader)
Deprecated.use try-with-resourcesstatic void
close(java.io.Writer writer)
Deprecated.use try-with-resourcesstatic void
close(java.nio.channels.Channel channel)
Deprecated.use try-with-resourcesstatic boolean
contentEquals(java.io.InputStream input1, java.io.InputStream input2)
Deprecated.useorg.apache.commons.io.IOUtils.contentEquals()
static void
copy(byte[] input, java.io.OutputStream output)
Deprecated.inline this methodstatic void
copy(byte[] input, java.io.Writer output)
Deprecated.always specify a character encodingstatic void
copy(byte[] input, java.io.Writer output, int bufferSize)
Deprecated.always specify a character encodingstatic void
copy(byte[] input, java.io.Writer output, java.lang.String encoding)
Deprecated.useorg.apache.commons.io.IOUtils.write()
.static void
copy(byte[] input, java.io.Writer output, java.lang.String encoding, int bufferSize)
Deprecated.useorg.apache.commons.io.IOUtils.write()
.static void
copy(java.io.InputStream input, java.io.OutputStream output)
Deprecated.useorg.apache.commons.io.IOUtils.copy()
or in Java 9 and laterInputStream.transferTo()
.static void
copy(java.io.InputStream input, java.io.OutputStream output, int bufferSize)
Deprecated.useorg.apache.commons.io.IOUtils.copy()
or in Java 9 and laterInputStream.transferTo()
.static void
copy(java.io.InputStream input, java.io.Writer output)
Deprecated.useorg.apache.commons.io.IOUtils.copy()
.static void
copy(java.io.InputStream input, java.io.Writer output, int bufferSize)
Deprecated.useorg.apache.commons.io.IOUtils.copy()
.static void
copy(java.io.InputStream input, java.io.Writer output, java.lang.String encoding)
Deprecated.useorg.apache.commons.io.IOUtils.copy()
.static void
copy(java.io.InputStream input, java.io.Writer output, java.lang.String encoding, int bufferSize)
Deprecated.useorg.apache.commons.io.IOUtils.copy()
.static void
copy(java.io.Reader input, java.io.OutputStream output)
Deprecated.always specify a character encodingstatic void
copy(java.io.Reader input, java.io.OutputStream output, int bufferSize)
Deprecated.always specify a character encodingstatic void
copy(java.io.Reader input, java.io.Writer output)
Deprecated.static void
copy(java.io.Reader input, java.io.Writer output, int bufferSize)
Deprecated.useorg.apache.commons.io.IOUtils.copy()
.static void
copy(java.lang.String input, java.io.OutputStream output)
Deprecated.always specify a character encodingstatic void
copy(java.lang.String input, java.io.OutputStream output, int bufferSize)
Deprecated.always specify a character encodingstatic void
copy(java.lang.String input, java.io.Writer output)
Deprecated.useorg.apache.commons.io.IOUtils.write()
.static byte[]
toByteArray(java.io.InputStream input)
Deprecated.useorg.apache.commons.io.IOUtils.readFully()
.static byte[]
toByteArray(java.io.InputStream input, int bufferSize)
Deprecated.useorg.apache.commons.io.IOUtils.readFully()
.static byte[]
toByteArray(java.io.Reader input)
Deprecated.always specify a character encodingstatic byte[]
toByteArray(java.io.Reader input, int bufferSize)
Deprecated.always specify a character encodingstatic byte[]
toByteArray(java.lang.String input)
Deprecated.always specify a character encodingstatic byte[]
toByteArray(java.lang.String input, int bufferSize)
Deprecated.always specify a character encodingstatic java.lang.String
toString(byte[] input)
Deprecated.always specify a character encodingstatic java.lang.String
toString(byte[] input, int bufferSize)
Deprecated.always specify a character encodingstatic java.lang.String
toString(byte[] input, java.lang.String encoding)
Deprecated.usenew String(input, encoding)
static java.lang.String
toString(byte[] input, java.lang.String encoding, int bufferSize)
Deprecated.usenew String(input, encoding)
static java.lang.String
toString(java.io.InputStream input)
Deprecated.always specify a character encodingstatic java.lang.String
toString(java.io.InputStream input, int bufferSize)
Deprecated.always specify a character encodingstatic java.lang.String
toString(java.io.InputStream input, java.lang.String encoding)
Deprecated.useorg.apache.commons.io.IOUtils.toString()
.static java.lang.String
toString(java.io.InputStream input, java.lang.String encoding, int bufferSize)
Deprecated.useorg.apache.commons.io.IOUtils.toString()
.static java.lang.String
toString(java.io.Reader input)
Deprecated.useorg.apache.commons.io.IOUtils.toString()
.static java.lang.String
toString(java.io.Reader input, int bufferSize)
Deprecated.useorg.apache.commons.io.IOUtils.toString()
.
-
-
-
Method Detail
-
copy
@Deprecated public static void copy(@Nonnull java.io.InputStream input, @Nonnull java.io.OutputStream output) throws java.io.IOException
Deprecated.useorg.apache.commons.io.IOUtils.copy()
or in Java 9 and laterInputStream.transferTo()
.Copy bytes from anInputStream
to anOutputStream
.- Parameters:
input
- the stream to read fromoutput
- the stream to write to- Throws:
java.io.IOException
- in case of an error
-
copy
@Deprecated public static void copy(@Nonnull java.io.InputStream input, @Nonnull java.io.OutputStream output, int bufferSize) throws java.io.IOException
Deprecated.useorg.apache.commons.io.IOUtils.copy()
or in Java 9 and laterInputStream.transferTo()
.Copy bytes from anInputStream
to anOutputStream
. In Java 9 and later this is replaced byInputStream.transferTo()
.- Parameters:
input
- the stream to read fromoutput
- the stream to write tobufferSize
- size of internal buffer- Throws:
java.io.IOException
- in case of an error
-
copy
@Deprecated public static void copy(@Nonnull java.io.Reader input, @Nonnull java.io.Writer output) throws java.io.IOException
Deprecated.Copy chars from aReader
to aWriter
.- Parameters:
input
- the reader to read fromoutput
- the writer to write to- Throws:
java.io.IOException
- in case of failure * @deprecated useorg.apache.commons.io.IOUtils.copy()
.
-
copy
@Deprecated public static void copy(@Nonnull java.io.Reader input, @Nonnull java.io.Writer output, int bufferSize) throws java.io.IOException
Deprecated.useorg.apache.commons.io.IOUtils.copy()
.Copy chars from aReader
to aWriter
.- Parameters:
input
- the reader to read fromoutput
- the writer to write tobufferSize
- size of internal buffer- Throws:
java.io.IOException
- in case of failure
-
copy
@Deprecated public static void copy(@Nonnull java.io.InputStream input, @Nonnull java.io.Writer output) throws java.io.IOException
Deprecated.useorg.apache.commons.io.IOUtils.copy()
.Copy and convert bytes from anInputStream
to chars on aWriter
. The platform's default encoding is used for the byte-to-char conversion.- Parameters:
input
- the reader to read fromoutput
- the writer to write to- Throws:
java.io.IOException
- in case of failure
-
copy
@Deprecated public static void copy(@Nonnull java.io.InputStream input, @Nonnull java.io.Writer output, int bufferSize) throws java.io.IOException
Deprecated.useorg.apache.commons.io.IOUtils.copy()
.Copy and convert bytes from anInputStream
to chars on aWriter
. The platform's default encoding is used for the byte-to-char conversion.- Parameters:
input
- the input stream to read fromoutput
- the writer to write tobufferSize
- size of internal buffer- Throws:
java.io.IOException
- in case of failure
-
copy
@Deprecated public static void copy(@Nonnull java.io.InputStream input, @Nonnull java.io.Writer output, @Nonnull java.lang.String encoding) throws java.io.IOException
Deprecated.useorg.apache.commons.io.IOUtils.copy()
.Copy and convert bytes from anInputStream
to chars on aWriter
, using the specified encoding.- Parameters:
input
- the input stream to read fromoutput
- the writer to write toencoding
- the name of a supported character encoding. See the IANA Charset Registry for a list of valid encoding types.- Throws:
java.io.IOException
- in case of failure
-
copy
@Deprecated public static void copy(@Nonnull java.io.InputStream input, @Nonnull java.io.Writer output, @Nonnull java.lang.String encoding, int bufferSize) throws java.io.IOException
Deprecated.useorg.apache.commons.io.IOUtils.copy()
.Copy and convert bytes from anInputStream
to chars on aWriter
, using the specified encoding.- Parameters:
encoding
- the name of a supported character encoding. See the IANA Charset Registry for a list of valid encoding types.input
- the input stream to read fromoutput
- the writer to write tobufferSize
- size of internal buffer- Throws:
java.io.IOException
- in case of failure
-
toString
@Deprecated @Nonnull public static java.lang.String toString(@Nonnull java.io.InputStream input) throws java.io.IOException
Deprecated.always specify a character encodingGet the contents of anInputStream
as a String. The platform's default encoding is used for the byte-to-char conversion.- Parameters:
input
- the InputStream to read from- Returns:
- the resulting string
- Throws:
java.io.IOException
- in case of failure
-
toString
@Deprecated @Nonnull public static java.lang.String toString(@Nonnull java.io.InputStream input, int bufferSize) throws java.io.IOException
Deprecated.always specify a character encodingGet the contents of anInputStream
as a String. The platform's default encoding is used for the byte-to-char conversion.- Parameters:
input
- the InputStream to read frombufferSize
- size of internal buffer- Returns:
- the resulting string
- Throws:
java.io.IOException
- in case of failure
-
toString
@Deprecated @Nonnull public static java.lang.String toString(@Nonnull java.io.InputStream input, @Nonnull java.lang.String encoding) throws java.io.IOException
Deprecated.useorg.apache.commons.io.IOUtils.toString()
.Get the contents of anInputStream
as a String.- Parameters:
input
- the InputStream to read fromencoding
- the name of a supported character encoding. See the IANA Charset Registry for a list of valid encoding types.- Returns:
- the converted string
- Throws:
java.io.IOException
- in case of failure
-
toString
@Deprecated @Nonnull public static java.lang.String toString(@Nonnull java.io.InputStream input, @Nonnull java.lang.String encoding, int bufferSize) throws java.io.IOException
Deprecated.useorg.apache.commons.io.IOUtils.toString()
.Get the contents of anInputStream
as a String.- Parameters:
input
- the InputStream to read fromencoding
- the name of a supported character encoding. See the IANA Charset Registry for a list of valid encoding types.bufferSize
- size of internal buffer- Returns:
- The converted string.
- Throws:
java.io.IOException
- in case of failure
-
toByteArray
@Deprecated @Nonnull public static byte[] toByteArray(@Nonnull java.io.InputStream input) throws java.io.IOException
Deprecated.useorg.apache.commons.io.IOUtils.readFully()
.Get the contents of anInputStream
as abyte[]
.- Parameters:
input
- the InputStream to read from- Returns:
- the resulting byte array.
- Throws:
java.io.IOException
- in case of failure
-
toByteArray
@Deprecated @Nonnull public static byte[] toByteArray(@Nonnull java.io.InputStream input, int bufferSize) throws java.io.IOException
Deprecated.useorg.apache.commons.io.IOUtils.readFully()
.Get the contents of anInputStream
as abyte[]
.- Parameters:
input
- the InputStream to read frombufferSize
- size of internal buffer- Returns:
- the resulting byte array.
- Throws:
java.io.IOException
- in case of failure
-
copy
@Deprecated public static void copy(@Nonnull java.io.Reader input, @Nonnull java.io.OutputStream output) throws java.io.IOException
Deprecated.always specify a character encodingSerialize chars from aReader
to bytes on anOutputStream
, and flush theOutputStream
.- Parameters:
input
- the InputStream to read fromoutput
- the output stream to write to- Throws:
java.io.IOException
- in case of failure
-
copy
@Deprecated public static void copy(@Nonnull java.io.Reader input, @Nonnull java.io.OutputStream output, int bufferSize) throws java.io.IOException
Deprecated.always specify a character encodingSerialize chars from aReader
to bytes on anOutputStream
, and flush theOutputStream
.- Parameters:
input
- the InputStream to read fromoutput
- the output to write tobufferSize
- size of internal buffer- Throws:
java.io.IOException
- in case of failure
-
toString
@Deprecated @Nonnull public static java.lang.String toString(@Nonnull java.io.Reader input) throws java.io.IOException
Deprecated.useorg.apache.commons.io.IOUtils.toString()
.Get the contents of aReader
as a String.- Parameters:
input
- the InputStream to read from- Returns:
- The converted string.
- Throws:
java.io.IOException
- in case of failure
-
toString
@Deprecated @Nonnull public static java.lang.String toString(@Nonnull java.io.Reader input, int bufferSize) throws java.io.IOException
Deprecated.useorg.apache.commons.io.IOUtils.toString()
.Get the contents of aReader
as a String.- Parameters:
input
- the reader to read frombufferSize
- size of internal buffer- Returns:
- the resulting byte array.
- Throws:
java.io.IOException
- in case of failure
-
toByteArray
@Deprecated @Nonnull public static byte[] toByteArray(@Nonnull java.io.Reader input) throws java.io.IOException
Deprecated.always specify a character encodingGet the contents of aReader
as abyte[]
.- Parameters:
input
- the InputStream to read from- Returns:
- the resulting byte array.
- Throws:
java.io.IOException
- in case of failure
-
toByteArray
@Deprecated @Nonnull public static byte[] toByteArray(@Nonnull java.io.Reader input, int bufferSize) throws java.io.IOException
Deprecated.always specify a character encodingGet the contents of aReader
as abyte[]
.- Parameters:
input
- the InputStream to read frombufferSize
- size of internal buffer- Returns:
- the resulting byte array.
- Throws:
java.io.IOException
- in case of failure
-
copy
@Deprecated public static void copy(@Nonnull java.lang.String input, @Nonnull java.io.OutputStream output) throws java.io.IOException
Deprecated.always specify a character encodingSerialize chars from aString
to bytes on anOutputStream
, and flush theOutputStream
.- Parameters:
input
- the InputStream to read fromoutput
- the output to write to- Throws:
java.io.IOException
- in case of failure
-
copy
@Deprecated public static void copy(@Nonnull java.lang.String input, @Nonnull java.io.OutputStream output, int bufferSize) throws java.io.IOException
Deprecated.always specify a character encodingSerialize chars from aString
to bytes on anOutputStream
, and flush theOutputStream
.- Parameters:
input
- the InputStream to read fromoutput
- the output to write tobufferSize
- size of internal buffer- Throws:
java.io.IOException
- in case of failure
-
copy
@Deprecated public static void copy(@Nonnull java.lang.String input, @Nonnull java.io.Writer output) throws java.io.IOException
Deprecated.useorg.apache.commons.io.IOUtils.write()
.Copy chars from aString
to aWriter
.- Parameters:
input
- the string to writeoutput
- resulting outputWriter
- Throws:
java.io.IOException
- in case of failure
-
toByteArray
@Deprecated @Nonnull public static byte[] toByteArray(@Nonnull java.lang.String input) throws java.io.IOException
Deprecated.always specify a character encodingGet the contents of aString
as abyte[]
.- Parameters:
input
- the String to read from- Returns:
- the resulting byte array
- Throws:
java.io.IOException
- in case of failure
-
toByteArray
@Deprecated @Nonnull public static byte[] toByteArray(@Nonnull java.lang.String input, int bufferSize) throws java.io.IOException
Deprecated.always specify a character encodingGet the contents of aString
as abyte[]
.- Parameters:
input
- the InputStream to read frombufferSize
- size of internal buffer- Returns:
- the resulting byte array
- Throws:
java.io.IOException
- in case of failure
-
copy
@Deprecated public static void copy(@Nonnull byte[] input, @Nonnull java.io.Writer output) throws java.io.IOException
Deprecated.always specify a character encodingCopy and convert bytes from abyte[]
to chars on aWriter
. The platform's default encoding is used for the byte-to-char conversion.- Parameters:
input
- the InputStream to read fromoutput
- the output to write to- Throws:
java.io.IOException
- in case of failure
-
copy
@Deprecated public static void copy(@Nonnull byte[] input, @Nonnull java.io.Writer output, int bufferSize) throws java.io.IOException
Deprecated.always specify a character encodingCopy and convert bytes from abyte[]
to chars on aWriter
. The platform's default encoding is used for the byte-to-char conversion.- Parameters:
input
- the InputStream to read fromoutput
- the output to write tobufferSize
- size of internal buffer- Throws:
java.io.IOException
- in case of failure
-
copy
@Deprecated public static void copy(@Nonnull byte[] input, @Nonnull java.io.Writer output, java.lang.String encoding) throws java.io.IOException
Deprecated.useorg.apache.commons.io.IOUtils.write()
.Copy and convert bytes from abyte[]
to chars on aWriter
, using the specified encoding.- Parameters:
encoding
- the name of a supported character encoding. See the IANA Charset Registry for a list of valid encoding types.input
- the data to writeoutput
- the writer to write to- Throws:
java.io.IOException
- in case of failure
-
copy
@Deprecated public static void copy(@Nonnull byte[] input, @Nonnull java.io.Writer output, @Nonnull java.lang.String encoding, int bufferSize) throws java.io.IOException
Deprecated.useorg.apache.commons.io.IOUtils.write()
.Copy and convert bytes from abyte[]
to chars on aWriter
, using the specified encoding.- Parameters:
encoding
- the name of a supported character encoding. See the IANA Charset Registry for a list of valid encoding types.input
- the input bytesoutput
- The output bufferWriter
bufferSize
- size of internal buffer- Throws:
java.io.IOException
- in case of failure
-
toString
@Deprecated @Nonnull public static java.lang.String toString(@Nonnull byte[] input) throws java.io.IOException
Deprecated.always specify a character encodingGet the contents of abyte[]
as a String. The platform's default encoding is used for the byte-to-char conversion.- Parameters:
input
- the input bytes- Returns:
- the resulting string
- Throws:
java.io.IOException
- in case of failure
-
toString
@Deprecated @Nonnull public static java.lang.String toString(@Nonnull byte[] input, int bufferSize) throws java.io.IOException
Deprecated.always specify a character encodingGet the contents of abyte[]
as a String. The platform's default encoding is used for the byte-to-char conversion.- Parameters:
bufferSize
- size of internal bufferinput
- the input bytes- Returns:
- the created string
- Throws:
java.io.IOException
- in case of failure
-
toString
@Deprecated @Nonnull public static java.lang.String toString(@Nonnull byte[] input, @Nonnull java.lang.String encoding) throws java.io.IOException
Deprecated.usenew String(input, encoding)
Get the contents of abyte[]
as a String.- Parameters:
encoding
- the name of a supported character encoding. See the IANA Charset Registry for a list of valid encoding types.input
- the input bytes- Returns:
- the resulting string
- Throws:
java.io.IOException
- in case of failure
-
toString
@Deprecated @Nonnull public static java.lang.String toString(@Nonnull byte[] input, @Nonnull java.lang.String encoding, int bufferSize) throws java.io.IOException
Deprecated.usenew String(input, encoding)
Get the contents of abyte[]
as a String.- Parameters:
encoding
- the name of a supported character encoding. See the IANA Charset Registry for a list of valid encoding types.bufferSize
- size of internal bufferinput
- input bytes- Returns:
- the resulting string
- Throws:
java.io.IOException
- in case of failure
-
copy
@Deprecated public static void copy(@Nonnull byte[] input, @Nonnull java.io.OutputStream output) throws java.io.IOException
Deprecated.inline this methodCopy bytes from abyte[]
to anOutputStream
.- Parameters:
input
- Input byte array.output
- output streamOutputStream
- Throws:
java.io.IOException
- in case of failure
-
contentEquals
@Deprecated public static boolean contentEquals(@Nonnull java.io.InputStream input1, @Nonnull java.io.InputStream input2) throws java.io.IOException
Deprecated.useorg.apache.commons.io.IOUtils.contentEquals()
Compare the contents of two streams to determine if they are equal or not.- Parameters:
input1
- the first streaminput2
- the second stream- Returns:
- true if the content of the streams are equal or they both don't exist, false otherwise
- Throws:
java.io.IOException
- in case of failure
-
close
@Deprecated public static void close(@Nullable java.nio.channels.Channel channel)
Deprecated.use try-with-resourcesCloses a
Channel
suppressing anyIOException
.Note: The use case justifying this method is a shortcoming of the Java language up to but not including Java 7. For any code targeting Java 7 or later use of this method is highly discouraged and the
try-with-resources
statement should be used instead. Care must be taken to not use this method in a wayIOException
s get suppressed incorrectly. You must close all resources in use inside thetry
block to not suppress exceptions in thefinally
block incorrectly by using this method.Example:
// Introduce variables for the resources and initialize them to null. This cannot throw an exception. Closeable resource1 = null; Closeable resource2 = null; try { // Obtain a resource object and assign it to variable resource1. This may throw an exception. // If successful, resource1 != null. resource1 = ... // Obtain a resource object and assign it to variable resource2. This may throw an exception. // If successful, resource2 != null. Not reached if an exception has been thrown above. resource2 = ... // Perform operations on the resources. This may throw an exception. Not reached if an exception has been // thrown above. Note: Treat the variables resource1 and resource2 the same way as if they would have been // declared with the final modifier - that is - do NOT write anyting like resource1 = something else or // resource2 = something else here. resource1 ... resource2 ... // Finally, close the resources and set the variables to null indicating successful completion. // This may throw an exception. Not reached if an exception has been thrown above. resource1.close(); resource1 = null; // Not reached if an exception has been thrown above. resource2.close(); resource2 = null; // All resources are closed at this point and all operations (up to here) completed successfully without // throwing an exception we would need to handle (by letting it propagate or by catching and handling it). } finally { // Cleanup any resource not closed in the try block due to an exception having been thrown and suppress any // exception this may produce to not stop the exception from the try block to be propagated. If the try // block completed successfully, all variables will have been set to null there and this will not do // anything. This is just to cleanup properly in case of an exception. IOUtil.close( resource1 ); IOUtil.close( resource2 ); // Without that utility method you would need to write the following: // // try // { // if ( resource1 != null ) // { // resource1.close(); // } // } // catch( IOException e ) // { // Suppressed. If resource1 != null, an exception has already been thrown in the try block we need to // propagate instead of this one. // } // finally // { // try // { // if ( resource2 != null ) // { // resource2.close(); // } // } // catch ( IOException e ) // { // Suppressed. If resource2 != null, an exception has already been thrown in the try block we need to // propagate instead of this one. // } // } }
- Parameters:
channel
- The channel to close ornull
.
-
close
@Deprecated public static void close(@Nullable java.io.InputStream inputStream)
Deprecated.use try-with-resourcesCloses an
InputStream
suppressing anyIOException
.Note: The use case justifying this method is a shortcoming of the Java language up to but not including Java 7. For any code targeting Java 7 or later use of this method is highly discouraged and the
try-with-resources
statement should be used instead. Care must be taken to not use this method in a wayIOException
s get suppressed incorrectly. You must close all resources in use inside thetry
block to not suppress exceptions in thefinally
block incorrectly by using this method.Example:
// Introduce variables for the resources and initialize them to null. This cannot throw an exception. Closeable resource1 = null; Closeable resource2 = null; try { // Obtain a resource object and assign it to variable resource1. This may throw an exception. // If successful, resource1 != null. resource1 = ... // Obtain a resource object and assign it to variable resource2. This may throw an exception. // If successful, resource2 != null. Not reached if an exception has been thrown above. resource2 = ... // Perform operations on the resources. This may throw an exception. Not reached if an exception has been // thrown above. Note: Treat the variables resource1 and resource2 the same way as if they would have been // declared with the final modifier - that is - do NOT write anyting like resource1 = something else or // resource2 = something else here. resource1 ... resource2 ... // Finally, close the resources and set the variables to null indicating successful completion. // This may throw an exception. Not reached if an exception has been thrown above. resource1.close(); resource1 = null; // This may throw an exception. Not reached if an exception has been thrown above. resource2.close(); resource2 = null; // All resources are closed at this point and all operations (up to here) completed successfully without // throwing an exception we would need to handle (by letting it propagate or by catching and handling it). } finally { // Cleanup any resource not closed in the try block due to an exception having been thrown and suppress any // exception this may produce to not stop the exception from the try block to be propagated. If the try // block completed successfully, all variables will have been set to null there and this will not do // anything. This is just to cleanup properly in case of an exception. IOUtil.close( resource1 ); IOUtil.close( resource2 ); // Without that utility method you would need to write the following: // // try // { // if ( resource1 != null ) // { // resource1.close(); // } // } // catch( IOException e ) // { // Suppressed. If resource1 != null, an exception has already been thrown in the try block we need to // propagate instead of this one. // } // finally // { // try // { // if ( resource2 != null ) // { // resource2.close(); // } // } // catch ( IOException e ) // { // Suppressed. If resource2 != null, an exception has already been thrown in the try block we need to // propagate instead of this one. // } // } }
- Parameters:
inputStream
- The stream to close ornull
.
-
close
@Deprecated public static void close(@Nullable java.io.OutputStream outputStream)
Deprecated.use try-with-resourcesCloses an
OutputStream
suppressing anyIOException
.Note: The use case justifying this method is a shortcoming of the Java language up to but not including Java 7. For any code targeting Java 7 or later use of this method is highly discouraged and the
try-with-resources
statement should be used instead. Care must be taken to not use this method in a wayIOException
s get suppressed incorrectly. You must close all resources in use inside thetry
block to not suppress exceptions in thefinally
block incorrectly by using this method.Example:
// Introduce variables for the resources and initialize them to null. This cannot throw an exception. Closeable resource1 = null; Closeable resource2 = null; try { // Obtain a resource object and assign it to variable resource1. This may throw an exception. // If successful, resource1 != null. resource1 = ... // Obtain a resource object and assign it to variable resource2. This may throw an exception. // If successful, resource2 != null. Not reached if an exception has been thrown above. resource2 = ... // Perform operations on the resources. This may throw an exception. Not reached if an exception has been // thrown above. Note: Treat the variables resource1 and resource2 the same way as if they would have been // declared with the final modifier - that is - do NOT write anyting like resource1 = something else or // resource2 = something else here. resource1 ... resource2 ... // Finally, close the resources and set the variables to null indicating successful completion. // This may throw an exception. Not reached if an exception has been thrown above. resource1.close(); resource1 = null; // This may throw an exception. Not reached if an exception has been thrown above. resource2.close(); resource2 = null; // All resources are closed at this point and all operations (up to here) completed successfully without // throwing an exception we would need to handle (by letting it propagate or by catching and handling it). } finally { // Cleanup any resource not closed in the try block due to an exception having been thrown and suppress any // exception this may produce to not stop the exception from the try block to be propagated. If the try // block completed successfully, all variables will have been set to null there and this will not do // anything. This is just to cleanup properly in case of an exception. IOUtil.close( resource1 ); IOUtil.close( resource2 ); // Without that utility method you would need to write the following: // // try // { // if ( resource1 != null ) // { // resource1.close(); // } // } // catch( IOException e ) // { // Suppressed. If resource1 != null, an exception has already been thrown in the try block we need to // propagate instead of this one. // } // finally // { // try // { // if ( resource2 != null ) // { // resource2.close(); // } // } // catch ( IOException e ) // { // Suppressed. If resource2 != null, an exception has already been thrown in the try block we need to // propagate instead of this one. // } // } }
- Parameters:
outputStream
- The stream to close ornull
.
-
close
@Deprecated public static void close(@Nullable java.io.Reader reader)
Deprecated.use try-with-resourcesCloses a
Reader
suppressing anyIOException
.Note: The use case justifying this method is a shortcoming of the Java language up to but not including Java 7. For any code targeting Java 7 or later use of this method is highly discouraged and the
try-with-resources
statement should be used instead. Care must be taken to not use this method in a wayIOException
s get suppressed incorrectly. You must close all resources in use inside thetry
block to not suppress exceptions in thefinally
block incorrectly by using this method.Example:
// Introduce variables for the resources and initialize them to null. This cannot throw an exception. Closeable resource1 = null; Closeable resource2 = null; try { // Obtain a resource object and assign it to variable resource1. This may throw an exception. // If successful, resource1 != null. resource1 = ... // Obtain a resource object and assign it to variable resource2. This may throw an exception. // If successful, resource2 != null. Not reached if an exception has been thrown above. resource2 = ... // Perform operations on the resources. This may throw an exception. Not reached if an exception has been // thrown above. Note: Treat the variables resource1 and resource2 the same way as if they would have been // declared with the final modifier - that is - do NOT write anyting like resource1 = something else or // resource2 = something else here. resource1 ... resource2 ... // Finally, close the resources and set the variables to null indicating successful completion. // This may throw an exception. Not reached if an exception has been thrown above. resource1.close(); resource1 = null; // This may throw an exception. Not reached if an exception has been thrown above. resource2.close(); resource2 = null; // All resources are closed at this point and all operations (up to here) completed successfully without // throwing an exception we would need to handle (by letting it propagate or by catching and handling it). } finally { // Cleanup any resource not closed in the try block due to an exception having been thrown and suppress any // exception this may produce to not stop the exception from the try block to be propagated. If the try // block completed successfully, all variables will have been set to null there and this will not do // anything. This is just to cleanup properly in case of an exception. IOUtil.close( resource1 ); IOUtil.close( resource2 ); // Without that utility method you would need to write the following: // // try // { // if ( resource1 != null ) // { // resource1.close(); // } // } // catch( IOException e ) // { // Suppressed. If resource1 != null, an exception has already been thrown in the try block we need to // propagate instead of this one. // } // finally // { // try // { // if ( resource2 != null ) // { // resource2.close(); // } // } // catch ( IOException e ) // { // Suppressed. If resource2 != null, an exception has already been thrown in the try block we need to // propagate instead of this one. // } // } }
- Parameters:
reader
- The reader to close ornull
.
-
close
@Deprecated public static void close(@Nullable java.io.Writer writer)
Deprecated.use try-with-resourcesCloses a
Writer
suppressing anyIOException
.Note: The use case justifying this method is a shortcoming of the Java language up to but not including Java 7. For any code targeting Java 7 or later use of this method is highly discouraged and the
try-with-resources
statement should be used instead. Care must be taken to not use this method in a wayIOException
s get suppressed incorrectly. You must close all resources in use inside thetry
block to not suppress exceptions in thefinally
block incorrectly by using this method.Example:
// Introduce variables for the resources and initialize them to null. This cannot throw an exception. Closeable resource1 = null; Closeable resource2 = null; try { // Obtain a resource object and assign it to variable resource1. This may throw an exception. // If successful, resource1 != null. resource1 = ... // Obtain a resource object and assign it to variable resource2. This may throw an exception. // If successful, resource2 != null. Not reached if an exception has been thrown above. resource2 = ... // Perform operations on the resources. This may throw an exception. Not reached if an exception has been // thrown above. Note: Treat the variables resource1 and resource2 the same way as if they would have been // declared with the final modifier - that is - do NOT write anyting like resource1 = something else or // resource2 = something else here. resource1 ... resource2 ... // Finally, close the resources and set the variables to null indicating successful completion. // This may throw an exception. Not reached if an exception has been thrown above. resource1.close(); resource1 = null; // This may throw an exception. Not reached if an exception has been thrown above. resource2.close(); resource2 = null; // All resources are closed at this point and all operations (up to here) completed successfully without // throwing an exception we would need to handle (by letting it propagate or by catching and handling it). } finally { // Cleanup any resource not closed in the try block due to an exception having been thrown and suppress any // exception this may produce to not stop the exception from the try block to be propagated. If the try // block completed successfully, all variables will have been set to null there and this will not do // anything. This is just to cleanup properly in case of an exception. IOUtil.close( resource1 ); IOUtil.close( resource2 ); // Without that utility method you would need to write the following: // // try // { // if ( resource1 != null ) // { // resource1.close(); // } // } // catch( IOException e ) // { // Suppressed. If resource1 != null, an exception has already been thrown in the try block we need to // propagate instead of this one. // } // finally // { // try // { // if ( resource2 != null ) // { // resource2.close(); // } // } // catch ( IOException e ) // { // Suppressed. If resource2 != null, an exception has already been thrown in the try block we need to // propagate instead of this one. // } // } }
- Parameters:
writer
- The writer to close ornull
.
-
-