All Implemented Interfaces:
Closeable, DataInput, AutoCloseable

A data input stream lets an application read primitive Java data types from an underlying input stream in a machine-independent way. An application uses a data output stream to write data that can later be read by a data input stream.

A DataInputStream is not safe for use by multiple concurrent threads. If a DataInputStream is to be used by more than one thread then access to the data input stream should be controlled by appropriate synchronization.

Since:
1.0
See Also:

  • Field Summary

  • Constructor Summary

    Constructors

    Creates a DataInputStream that uses the specified underlying InputStream.

  • Method Summary

    final int

    read(byte[] b)

    Reads some number of bytes from the contained input stream and stores them into the buffer array b.

    final int

    read(byte[] b, int off, int len)

    Reads up to len bytes of data from the contained input stream into an array of bytes.

    final boolean

    See the general contract of the readBoolean method of DataInput.

    final byte

    readByte()

    See the general contract of the readByte method of DataInput.

    final char

    readChar()

    See the general contract of the readChar method of DataInput.

    final double

    See the general contract of the readDouble method of DataInput.

    final float

    readFloat()

    See the general contract of the readFloat method of DataInput.

    final void

    readFully(byte[] b)

    See the general contract of the readFully method of DataInput.

    final void

    readFully(byte[] b, int off, int len)

    See the general contract of the readFully method of DataInput.

    final int

    readInt()

    See the general contract of the readInt method of DataInput.

    readLine()

    final long

    readLong()

    See the general contract of the readLong method of DataInput.

    final short

    readShort()

    See the general contract of the readShort method of DataInput.

    final int

    See the general contract of the readUnsignedByte method of DataInput.

    final int

    See the general contract of the readUnsignedShort method of DataInput.

    readUTF()

    See the general contract of the readUTF method of DataInput.

    Reads from the stream in a representation of a Unicode character string encoded in modified UTF-8 format; this string of characters is then returned as a String.

    final int

    skipBytes(int n)

    See the general contract of the skipBytes method of DataInput.

    Methods declared in class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • DataInputStream

      Creates a DataInputStream that uses the specified underlying InputStream.

      Parameters:
      in - the specified input stream

  • Method Details

    • read

      public final int read(byte[] b) throws IOException

      Reads some number of bytes from the contained input stream and stores them into the buffer array b. The number of bytes actually read is returned as an integer. This method blocks until input data is available, end of file is detected, or an exception is thrown.

      If b is null, a NullPointerException is thrown. If the length of b is zero, then no bytes are read and 0 is returned; otherwise, there is an attempt to read at least one byte. If no byte is available because the stream is at end of file, the value -1 is returned; otherwise, at least one byte is read and stored into b.

      The first byte read is stored into element b[0], the next one into b[1], and so on. The number of bytes read is, at most, equal to the length of b. Let k be the number of bytes actually read; these bytes will be stored in elements b[0] through b[k-1], leaving elements b[k] through b[b.length-1] unaffected.

      The read(b) method has the same effect as: 

       read(b, 0, b.length)
      Overrides:
      read in class FilterInputStream
      Parameters:
      b - the buffer into which the data is read.
      Returns:
      the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.
      Throws:
      IOException - if the first byte cannot be read for any reason other than end of file, the stream has been closed and the underlying input stream does not support reading after close, or another I/O error occurs.
      See Also:

    • read

      public final int read(byte[] b, int off, int len) throws IOException

      Reads up to len bytes of data from the contained input stream into an array of bytes. An attempt is made to read as many as len bytes, but a smaller number may be read, possibly zero. The number of bytes actually read is returned as an integer.

      This method blocks until input data is available, end of file is detected, or an exception is thrown.

      If len is zero, then no bytes are read and 0 is returned; otherwise, there is an attempt to read at least one byte. If no byte is available because the stream is at end of file, the value -1 is returned; otherwise, at least one byte is read and stored into b.

      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. Let k be the number of bytes actually read; these bytes will be stored in elements b[off] through b[off+k-1], leaving elements b[off+k] through b[off+len-1] unaffected.

      In every case, elements b[0] through b[off] and elements b[off+len] through b[b.length-1] are unaffected.

      Overrides:
      read in class FilterInputStream
      Parameters:
      b - the buffer into which the data is read.
      off - the start offset in the destination array b
      len - the maximum number of bytes read.
      Returns:
      the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.
      Throws:
      NullPointerException - If b is null.
      IndexOutOfBoundsException - If off is negative, len is negative, or len is greater than b.length - off
      IOException - if the first byte cannot be read for any reason other than end of file, the stream has been closed and the underlying input stream does not support reading after close, or another I/O error occurs.
      See Also:

    • readFully

      public final void readFully(byte[] b) throws IOException

      See the general contract of the readFully method of DataInput.

      Bytes for this operation are read from the contained input stream.

      Specified by:
      readFully in interface DataInput
      Parameters:
      b - the buffer into which the data is read.
      Throws:
      NullPointerException - if b is null.
      EOFException - if this input stream reaches the end before reading all the bytes.
      IOException - the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.
      See Also:

    • readFully

      public final void readFully(byte[] b, int off, int len) throws IOException

      See the general contract of the readFully method of DataInput.

      Bytes for this operation are read from the contained input stream.

      Specified by:
      readFully in interface DataInput
      Parameters:
      b - the buffer into which the data is read.
      off - the start offset in the data array b.
      len - the number of bytes to read.
      Throws:
      NullPointerException - if b is null.
      IndexOutOfBoundsException - if off is negative, len is negative, or len is greater than b.length - off.
      EOFException - if this input stream reaches the end before reading all the bytes.
      IOException - the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.
      See Also:

    • skipBytes

      public final int skipBytes(int n) throws IOException

      See the general contract of the skipBytes method of DataInput.

      Bytes for this operation are read from the contained input stream.

      Specified by:
      skipBytes in interface DataInput
      Parameters:
      n - the number of bytes to be skipped.
      Returns:
      the actual number of bytes skipped.
      Throws:
      IOException - if the contained input stream does not support seek, or the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.

    • readBoolean

      public final boolean readBoolean() throws IOException

      See the general contract of the readBoolean method of DataInput.

      Bytes for this operation are read from the contained input stream.

      Specified by:
      readBoolean in interface DataInput
      Returns:
      the boolean value read.
      Throws:
      EOFException - if this input stream has reached the end.
      IOException - the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.
      See Also:

    • readByte

      public final byte readByte() throws IOException

      See the general contract of the readByte method of DataInput.

      Bytes for this operation are read from the contained input stream.

      Specified by:
      readByte in interface DataInput
      Returns:
      the next byte of this input stream as a signed 8-bit byte.
      Throws:
      EOFException - if this input stream has reached the end.
      IOException - the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.
      See Also:

    • readUnsignedByte

      public final int readUnsignedByte() throws IOException

      See the general contract of the readUnsignedByte method of DataInput.

      Bytes for this operation are read from the contained input stream.

      Specified by:
      readUnsignedByte in interface DataInput
      Returns:
      the next byte of this input stream, interpreted as an unsigned 8-bit number.
      Throws:
      EOFException - if this input stream has reached the end.
      IOException - the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.
      See Also:

    • readShort

      public final short readShort() throws IOException

      See the general contract of the readShort method of DataInput.

      Bytes for this operation are read from the contained input stream.

      Specified by:
      readShort in interface DataInput
      Returns:
      the next two bytes of this input stream, interpreted as a signed 16-bit number.
      Throws:
      EOFException - if this input stream reaches the end before reading two bytes.
      IOException - the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.
      See Also:

    • readUnsignedShort

      public final int readUnsignedShort() throws IOException

      See the general contract of the readUnsignedShort method of DataInput.

      Bytes for this operation are read from the contained input stream.

      Specified by:
      readUnsignedShort in interface DataInput
      Returns:
      the next two bytes of this input stream, interpreted as an unsigned 16-bit integer.
      Throws:
      EOFException - if this input stream reaches the end before reading two bytes.
      IOException - the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.
      See Also:

    • readChar

      public final char readChar() throws IOException

      See the general contract of the readChar method of DataInput.

      Bytes for this operation are read from the contained input stream.

      Specified by:
      readChar in interface DataInput
      Returns:
      the next two bytes of this input stream, interpreted as a char.
      Throws:
      EOFException - if this input stream reaches the end before reading two bytes.
      IOException - the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.
      See Also:

    • readInt

      public final int readInt() throws IOException

      See the general contract of the readInt method of DataInput.

      Bytes for this operation are read from the contained input stream.

      Specified by:
      readInt in interface DataInput
      Returns:
      the next four bytes of this input stream, interpreted as an int.
      Throws:
      EOFException - if this input stream reaches the end before reading four bytes.
      IOException - the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.
      See Also:

    • readLong

      public final long readLong() throws IOException

      See the general contract of the readLong method of DataInput.

      Bytes for this operation are read from the contained input stream.

      Specified by:
      readLong in interface DataInput
      Returns:
      the next eight bytes of this input stream, interpreted as a long.
      Throws:
      EOFException - if this input stream reaches the end before reading eight bytes.
      IOException - the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.
      See Also:

    • readFloat

      public final float readFloat() throws IOException

      See the general contract of the readFloat method of DataInput.

      Bytes for this operation are read from the contained input stream.

      Specified by:
      readFloat in interface DataInput
      Returns:
      the next four bytes of this input stream, interpreted as a float.
      Throws:
      EOFException - if this input stream reaches the end before reading four bytes.
      IOException - the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.
      See Also:

    • readDouble

      public final double readDouble() throws IOException

      See the general contract of the readDouble method of DataInput.

      Bytes for this operation are read from the contained input stream.

      Specified by:
      readDouble in interface DataInput
      Returns:
      the next eight bytes of this input stream, interpreted as a double.
      Throws:
      EOFException - if this input stream reaches the end before reading eight bytes.
      IOException - the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.
      See Also:

    • readLine

      See the general contract of the readLine method of DataInput.

      Bytes for this operation are read from the contained input stream.

      Specified by:
      readLine in interface DataInput
      Returns:
      the next line of text from this input stream.
      Throws:
      IOException - if an I/O error occurs.
      See Also:

    • readUTF

      See the general contract of the readUTF method of DataInput.

      Bytes for this operation are read from the contained input stream.

      Specified by:
      readUTF in interface DataInput
      Returns:
      a Unicode string.
      Throws:
      EOFException - if this input stream reaches the end before reading all the bytes.
      IOException - the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.
      UTFDataFormatException - if the bytes do not represent a valid modified UTF-8 encoding of a string.
      See Also:

    • readUTF

      Reads from the stream in a representation of a Unicode character string encoded in modified UTF-8 format; this string of characters is then returned as a String. The details of the modified UTF-8 representation are exactly the same as for the readUTF method of DataInput.

      Parameters:
      in - a data input stream.
      Returns:
      a Unicode string.
      Throws:
      EOFException - if the input stream reaches the end before all the bytes.
      IOException - the stream has been closed and the contained input stream does not support reading after close, or another I/O error occurs.
      UTFDataFormatException - if the bytes do not represent a valid modified UTF-8 encoding of a Unicode string.
      See Also: