ByteStreams (Guava: Google Core Libraries for Java 20.0 API)

java.lang.Object
- com.google.common.io.ByteStreams

```
@Beta
 @GwtIncompatible
public final class ByteStreams
extends Object
```
Provides utility methods for working with byte arrays and I/O streams.

Since:

1.0

Author:

Chris Nokleberg, Colin Decker

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static long`	`copy(InputStream from, OutputStream to)` Copies all bytes from the input stream to the output stream.
`static long`	`copy(ReadableByteChannel from, WritableByteChannel to)` Copies all bytes from the readable channel to the writable channel.
`static long`	`exhaust(InputStream in)` Reads and discards data from the given `InputStream` until the end of the stream is reached.
`static InputStream`	`limit(InputStream in, long limit)` Wraps a `InputStream`, limiting the number of bytes which can be read.
`static ByteArrayDataInput`	`newDataInput(byte[] bytes)` Returns a new `ByteArrayDataInput` instance to read from the `bytes` array from the beginning.
`static ByteArrayDataInput`	`newDataInput(byte[] bytes, int start)` Returns a new `ByteArrayDataInput` instance to read from the `bytes` array, starting at the given position.
`static ByteArrayDataInput`	`newDataInput(ByteArrayInputStream byteArrayInputStream)` Returns a new `ByteArrayDataInput` instance to read from the given `ByteArrayInputStream`.
`static ByteArrayDataOutput`	`newDataOutput()` Returns a new `ByteArrayDataOutput` instance with a default size.
`static ByteArrayDataOutput`	`newDataOutput(ByteArrayOutputStream byteArrayOutputSteam)` Returns a new `ByteArrayDataOutput` instance which writes to the given `ByteArrayOutputStream`.
`static ByteArrayDataOutput`	`newDataOutput(int size)` Returns a new `ByteArrayDataOutput` instance sized to hold `size` bytes before resizing.
`static OutputStream`	`nullOutputStream()` Returns an `OutputStream` that simply discards written bytes.
`static int`	`read(InputStream in, byte[] b, int off, int len)` Reads some bytes from an input stream and stores them into the buffer array `b`.
`static <T> T`	`readBytes(InputStream input, ByteProcessor<T> processor)` Process the bytes of the given input stream using the given processor.
`static void`	`readFully(InputStream in, byte[] b)` Attempts to read enough bytes from the stream to fill the given byte array, with the same behavior as `DataInput.readFully(byte[])`.
`static void`	`readFully(InputStream in, byte[] b, int off, int len)` Attempts to read `len` bytes from the stream into the given array starting at `off`, with the same behavior as `DataInput.readFully(byte[], int, int)`.
`static void`	`skipFully(InputStream in, long n)` Discards `n` bytes of data from the input stream.
`static byte[]`	`toByteArray(InputStream in)` Reads all bytes from an input stream into a byte array.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - copy
```
public static long copy(InputStream from,
                        OutputStream to)
                 throws IOException
```
    Copies all bytes from the input stream to the output stream. Does not close or flush either stream.
    
    Parameters:
    
    from - the input stream to read from
    
    to - the output stream to write to
    
    Returns:
    
    the number of bytes copied
    
    Throws:
    
    IOException - if an I/O error occurs
  - copy
```
public static long copy(ReadableByteChannel from,
                        WritableByteChannel to)
                 throws IOException
```
    Copies all bytes from the readable channel to the writable channel. Does not close or flush either channel.
    
    Parameters:
    
    from - the readable channel to read from
    
    to - the writable channel to write to
    
    Returns:
    
    the number of bytes copied
    
    Throws:
    
    IOException - if an I/O error occurs
  - toByteArray
```
public static byte[] toByteArray(InputStream in)
                          throws IOException
```
    Reads all bytes from an input stream into a byte array. Does not close the stream.
    
    Parameters:
    
    in - the input stream to read from
    
    Returns:
    
    a byte array containing all the bytes from the stream
    
    Throws:
    
    IOException - if an I/O error occurs
  - exhaust
```
public static long exhaust(InputStream in)
                    throws IOException
```
    Reads and discards data from the given InputStream until the end of the stream is reached. Returns the total number of bytes read. Does not close the stream.
    
    Throws:
    
    IOException
    
    Since:
    
    20.0
  - newDataInput
```
public static ByteArrayDataInput newDataInput(byte[] bytes)
```
    Returns a new ByteArrayDataInput instance to read from the bytes array from the beginning.
  - newDataInput
```
public static ByteArrayDataInput newDataInput(byte[] bytes,
                                              int start)
```
    Returns a new ByteArrayDataInput instance to read from the bytes array, starting at the given position.
    
    Throws:
    
    IndexOutOfBoundsException - if start is negative or greater than the length of the array
  - newDataInput
```
public static ByteArrayDataInput newDataInput(ByteArrayInputStream byteArrayInputStream)
```
    Returns a new ByteArrayDataInput instance to read from the given ByteArrayInputStream. The given input stream is not reset before being read from by the returned ByteArrayDataInput.
    
    Since:
    
    17.0
  - newDataOutput
```
public static ByteArrayDataOutput newDataOutput()
```
    Returns a new ByteArrayDataOutput instance with a default size.
  - newDataOutput
```
public static ByteArrayDataOutput newDataOutput(int size)
```
    Returns a new ByteArrayDataOutput instance sized to hold size bytes before resizing.
    
    Throws:
    
    IllegalArgumentException - if size is negative
  - newDataOutput
```
public static ByteArrayDataOutput newDataOutput(ByteArrayOutputStream byteArrayOutputSteam)
```
    Returns a new ByteArrayDataOutput instance which writes to the given ByteArrayOutputStream. The given output stream is not reset before being written to by the returned ByteArrayDataOutput and new data will be appended to any existing content.
    Note that if the given output stream was not empty or is modified after the ByteArrayDataOutput is created, the contract for ByteArrayDataOutput.toByteArray() will not be honored (the bytes returned in the byte array may not be exactly what was written via calls to ByteArrayDataOutput).
    
    Since:
    
    17.0
  - nullOutputStream
```
public static OutputStream nullOutputStream()
```
    Returns an OutputStream that simply discards written bytes.
    
    Since:
    
    14.0 (since 1.0 as com.google.common.io.NullOutputStream)
  - limit
```
public static InputStream limit(InputStream in,
                                long limit)
```
    Wraps a InputStream, limiting the number of bytes which can be read.
    
    Parameters:
    
    in - the input stream to be wrapped
    
    limit - the maximum number of bytes to be read
    
    Returns:
    
    a length-limited InputStream
    
    Since:
    
    14.0 (since 1.0 as com.google.common.io.LimitInputStream)
  - readFully
```
public static void readFully(InputStream in,
                             byte[] b)
                      throws IOException
```
    Attempts to read enough bytes from the stream to fill the given byte array, with the same behavior as DataInput.readFully(byte[]). Does not close the stream.
    
    Parameters:
    
    in - the input stream to read from.
    
    b - the buffer into which the data is read.
    
    Throws:
    
    EOFException - if this stream reaches the end before reading all the bytes.
    
    IOException - if an I/O error occurs.
  - readFully
```
public static void readFully(InputStream in,
                             byte[] b,
                             int off,
                             int len)
                      throws IOException
```
    Attempts to read len bytes from the stream into the given array starting at off, with the same behavior as DataInput.readFully(byte[], int, int). Does not close the stream.
    
    Parameters:
    
    in - the input stream to read from.
    
    b - the buffer into which the data is read.
    
    off - an int specifying the offset into the data.
    
    len - an int specifying the number of bytes to read.
    
    Throws:
    
    EOFException - if this stream reaches the end before reading all the bytes.
    
    IOException - if an I/O error occurs.
  - skipFully
```
public static void skipFully(InputStream in,
                             long n)
                      throws IOException
```
    Discards n bytes of data from the input stream. This method will block until the full amount has been skipped. Does not close the stream.
    
    Parameters:
    
    in - the input stream to read from
    
    n - the number of bytes to skip
    
    Throws:
    
    EOFException - if this stream reaches the end before skipping all the bytes
    
    IOException - if an I/O error occurs, or the stream does not support skipping
  - readBytes
```
public static <T> T readBytes(InputStream input,
                              ByteProcessor<T> processor)
                       throws IOException
```
    Process the bytes of the given input stream using the given processor.
    
    Parameters:
    
    input - the input stream to process
    
    processor - the object to which to pass the bytes of the stream
    
    Returns:
    
    the result of the byte processor
    
    Throws:
    
    IOException - if an I/O error occurs
    
    Since:
    
    14.0
  - read
```
public static int read(InputStream in,
                       byte[] b,
                       int off,
                       int len)
                throws IOException
```
    Reads some bytes from an input stream and stores them into the buffer array b. This method blocks until len bytes of input data have been read into the array, or end of file is detected. The number of bytes read is returned, possibly zero. Does not close the stream.
    A caller can detect EOF if the number of bytes read is less than len. All subsequent calls on the same stream will return zero.
    If b is null, a NullPointerException is thrown. If off is negative, or len is negative, or off+len is greater than the length of the array b, then an IndexOutOfBoundsException is thrown. If len is zero, then no bytes are read. Otherwise, the first byte read is stored into element b[off], the next one into b[off+1], and so on. The number of bytes read is, at most, equal to len.
    
    Parameters:
    
    in - the input stream to read from
    
    b - the buffer into which the data is read
    
    off - an int specifying the offset into the data
    
    len - an int specifying the number of bytes to read
    
    Returns:
    
    the number of bytes read
    
    Throws:
    
    IOException - if an I/O error occurs

Class ByteStreams

Method Summary

Methods inherited from class java.lang.Object

Method Detail

copy

copy

toByteArray

exhaust

newDataInput

newDataInput

newDataInput

newDataOutput

newDataOutput

newDataOutput

nullOutputStream

limit

readFully

readFully

skipFully

readBytes

read