Class DataInputStream
- All Implemented Interfaces:
Closeable,DataInput,AutoCloseable
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:
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Field Summary
Fields declared in class java.io.FilterInputStream
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Constructor Summary
ConstructorsConstructorDescriptionCreates a DataInputStream that uses the specified underlying InputStream. -
Method Summary
Modifier and TypeMethodDescriptionfinal intread(byte[] b) Reads some number of bytes from the contained input stream and stores them into the buffer arrayb.final intread(byte[] b, int off, int len) Reads up tolenbytes of data from the contained input stream into an array of bytes.final booleanSee the general contract of thereadBooleanmethod ofDataInput.final bytereadByte()See the general contract of thereadBytemethod ofDataInput.final charreadChar()See the general contract of thereadCharmethod ofDataInput.final doubleSee the general contract of thereadDoublemethod ofDataInput.final floatSee the general contract of thereadFloatmethod ofDataInput.final voidreadFully(byte[] b) See the general contract of thereadFullymethod ofDataInput.final voidreadFully(byte[] b, int off, int len) See the general contract of thereadFullymethod ofDataInput.final intreadInt()See the general contract of thereadIntmethod ofDataInput.final StringreadLine()Deprecated.This method does not properly convert bytes to characters.final longreadLong()See the general contract of thereadLongmethod ofDataInput.final shortSee the general contract of thereadShortmethod ofDataInput.final intSee the general contract of thereadUnsignedBytemethod ofDataInput.final intSee the general contract of thereadUnsignedShortmethod ofDataInput.final StringreadUTF()See the general contract of thereadUTFmethod ofDataInput.static final StringReads from the streamina representation of a Unicode character string encoded in modified UTF-8 format; this string of characters is then returned as aString.final intskipBytes(int n) See the general contract of theskipBytesmethod ofDataInput.Methods declared in class java.io.FilterInputStream
available, close, mark, markSupported, read, reset, skipMethods declared in class java.io.InputStream
nullInputStream, readAllBytes, readNBytes, readNBytes, skipNBytes, transferTo
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Constructor Details
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DataInputStream
Creates a DataInputStream that uses the specified underlying InputStream.- Parameters:
in- the specified input stream
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Method Details
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read
Reads some number of bytes from the contained input stream and stores them into the buffer arrayb. 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
bis null, aNullPointerExceptionis thrown. If the length ofbis zero, then no bytes are read and0is 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-1is returned; otherwise, at least one byte is read and stored intob.The first byte read is stored into element
b[0], the next one intob[1], and so on. The number of bytes read is, at most, equal to the length ofb. Letkbe the number of bytes actually read; these bytes will be stored in elementsb[0]throughb[k-1], leaving elementsb[k]throughb[b.length-1]unaffected.The
read(b)method has the same effect as:read(b, 0, b.length)
- Overrides:
readin classFilterInputStream- Parameters:
b- the buffer into which the data is read.- Returns:
- the total number of bytes read into the buffer, or
-1if 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:
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read
Reads up tolenbytes of data from the contained input stream into an array of bytes. An attempt is made to read as many aslenbytes, 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
lenis zero, then no bytes are read and0is 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-1is returned; otherwise, at least one byte is read and stored intob.The first byte read is stored into element
b[off], the next one intob[off+1], and so on. The number of bytes read is, at most, equal tolen. Let k be the number of bytes actually read; these bytes will be stored in elementsb[off]throughb[off+k-1], leaving elementsb[off+k]throughb[off+len-1]unaffected.In every case, elements
b[0]throughb[off]and elementsb[off+len]throughb[b.length-1]are unaffected.- Overrides:
readin classFilterInputStream- Parameters:
b- the buffer into which the data is read.off- the start offset in the destination arrayblen- the maximum number of bytes read.- Returns:
- the total number of bytes read into the buffer, or
-1if there is no more data because the end of the stream has been reached. - Throws:
NullPointerException- Ifbisnull.IndexOutOfBoundsException- Ifoffis negative,lenis negative, orlenis greater thanb.length - offIOException- 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:
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readFully
See the general contract of thereadFullymethod ofDataInput.Bytes for this operation are read from the contained input stream.
- Specified by:
readFullyin interfaceDataInput- Parameters:
b- the buffer into which the data is read.- Throws:
NullPointerException- ifbisnull.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:
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readFully
See the general contract of thereadFullymethod ofDataInput.Bytes for this operation are read from the contained input stream.
- Specified by:
readFullyin interfaceDataInput- Parameters:
b- the buffer into which the data is read.off- the start offset in the data arrayb.len- the number of bytes to read.- Throws:
NullPointerException- ifbisnull.IndexOutOfBoundsException- ifoffis negative,lenis negative, orlenis greater thanb.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:
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skipBytes
See the general contract of theskipBytesmethod ofDataInput.Bytes for this operation are read from the contained input stream.
- Specified by:
skipBytesin interfaceDataInput- 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.
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readBoolean
See the general contract of thereadBooleanmethod ofDataInput.Bytes for this operation are read from the contained input stream.
- Specified by:
readBooleanin interfaceDataInput- Returns:
- the
booleanvalue 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:
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readByte
See the general contract of thereadBytemethod ofDataInput.Bytes for this operation are read from the contained input stream.
- Specified by:
readBytein interfaceDataInput- 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:
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readUnsignedByte
See the general contract of thereadUnsignedBytemethod ofDataInput.Bytes for this operation are read from the contained input stream.
- Specified by:
readUnsignedBytein interfaceDataInput- 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:
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readShort
See the general contract of thereadShortmethod ofDataInput.Bytes for this operation are read from the contained input stream.
- Specified by:
readShortin interfaceDataInput- 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:
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readUnsignedShort
See the general contract of thereadUnsignedShortmethod ofDataInput.Bytes for this operation are read from the contained input stream.
- Specified by:
readUnsignedShortin interfaceDataInput- 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:
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readChar
See the general contract of thereadCharmethod ofDataInput.Bytes for this operation are read from the contained input stream.
- Specified by:
readCharin interfaceDataInput- 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:
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readInt
See the general contract of thereadIntmethod ofDataInput.Bytes for this operation are read from the contained input stream.
- Specified by:
readIntin interfaceDataInput- 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:
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readLong
See the general contract of thereadLongmethod ofDataInput.Bytes for this operation are read from the contained input stream.
- Specified by:
readLongin interfaceDataInput- 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:
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readFloat
See the general contract of thereadFloatmethod ofDataInput.Bytes for this operation are read from the contained input stream.
- Specified by:
readFloatin interfaceDataInput- 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:
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readDouble
See the general contract of thereadDoublemethod ofDataInput.Bytes for this operation are read from the contained input stream.
- Specified by:
readDoublein interfaceDataInput- 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:
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readLine
Deprecated.This method does not properly convert bytes to characters. As of JDK 1.1, the preferred way to read lines of text is via theBufferedReader.readLine()method. Programs that use theDataInputStreamclass to read lines can be converted to use theBufferedReaderclass by replacing code of the form:
with:DataInputStream d = new DataInputStream(in);BufferedReader d = new BufferedReader(new InputStreamReader(in));See the general contract of thereadLinemethod ofDataInput.Bytes for this operation are read from the contained input stream.
- Specified by:
readLinein interfaceDataInput- Returns:
- the next line of text from this input stream.
- Throws:
IOException- if an I/O error occurs.- See Also:
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readUTF
See the general contract of thereadUTFmethod ofDataInput.Bytes for this operation are read from the contained input stream.
- Specified by:
readUTFin interfaceDataInput- 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:
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readUTF
Reads from the streamina representation of a Unicode character string encoded in modified UTF-8 format; this string of characters is then returned as aString. The details of the modified UTF-8 representation are exactly the same as for thereadUTFmethod ofDataInput.- 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:
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