- java.lang.Object
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- java.io.InputStream
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- java.io.FilterInputStream
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- java.io.DataInputStream
 
 
 
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- All Implemented Interfaces:
- Closeable,- DataInput,- AutoCloseable
 
 public class DataInputStream extends FilterInputStream implements DataInput 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.DataInputStream is not necessarily safe for multithreaded access. Thread safety is optional and is the responsibility of users of methods in this class. - Since:
- 1.0
- See Also:
- DataOutputStream
 
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Field Summary- 
Fields declared in class java.io.FilterInputStreamin
 
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Constructor SummaryConstructors Constructor Description DataInputStream(InputStream in)Creates a DataInputStream that uses the specified underlying InputStream.
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Method SummaryAll Methods Static Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description intread(byte[] b)Reads some number of bytes from the contained input stream and stores them into the buffer arrayb.intread(byte[] b, int off, int len)Reads up tolenbytes of data from the contained input stream into an array of bytes.booleanreadBoolean()See the general contract of thereadBooleanmethod ofDataInput.bytereadByte()See the general contract of thereadBytemethod ofDataInput.charreadChar()See the general contract of thereadCharmethod ofDataInput.doublereadDouble()See the general contract of thereadDoublemethod ofDataInput.floatreadFloat()See the general contract of thereadFloatmethod ofDataInput.voidreadFully(byte[] b)See the general contract of thereadFullymethod ofDataInput.voidreadFully(byte[] b, int off, int len)See the general contract of thereadFullymethod ofDataInput.intreadInt()See the general contract of thereadIntmethod ofDataInput.StringreadLine()Deprecated.This method does not properly convert bytes to characters.longreadLong()See the general contract of thereadLongmethod ofDataInput.shortreadShort()See the general contract of thereadShortmethod ofDataInput.intreadUnsignedByte()See the general contract of thereadUnsignedBytemethod ofDataInput.intreadUnsignedShort()See the general contract of thereadUnsignedShortmethod ofDataInput.StringreadUTF()See the general contract of thereadUTFmethod ofDataInput.static StringreadUTF(DataInput in)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.intskipBytes(int n)See the general contract of theskipBytesmethod ofDataInput.- 
Methods declared in class java.io.FilterInputStreamavailable, close, mark, markSupported, read, reset, skip
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Methods declared in class java.io.InputStreamnullInputStream, readAllBytes, readNBytes, readNBytes, transferTo
 
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Constructor Detail- 
DataInputStreampublic DataInputStream(InputStream in) Creates a DataInputStream that uses the specified underlying InputStream.- Parameters:
- in- the specified input stream
 
 
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Method Detail- 
readpublic final int read(byte[] b) throws IOExceptionReads 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 class- FilterInputStream
- 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:
- FilterInputStream.in,- InputStream.read(byte[], int, int)
 
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readpublic final int read(byte[] b, int off, int len) throws IOExceptionReads 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 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
             -1if there is no more data because the end of the stream has been reached.
- Throws:
- NullPointerException- If- bis- null.
- IndexOutOfBoundsException- If- offis negative,- lenis negative, or- lenis 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:
- FilterInputStream.in,- InputStream.read(byte[], int, int)
 
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readFullypublic final void readFully(byte[] b) throws IOExceptionSee the general contract of thereadFullymethod ofDataInput.Bytes for this operation are read from the contained input stream. - Specified by:
- readFullyin interface- DataInput
- Parameters:
- b- the buffer into which the data is read.
- Throws:
- NullPointerException- if- bis- 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:
- FilterInputStream.in
 
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readFullypublic final void readFully(byte[] b, int off, int len) throws IOExceptionSee the general contract of thereadFullymethod ofDataInput.Bytes for this operation are read from the contained input stream. - Specified by:
- readFullyin 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- bis- null.
- IndexOutOfBoundsException- if- offis negative,- lenis negative, or- lenis 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:
- FilterInputStream.in
 
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skipBytespublic final int skipBytes(int n) throws IOExceptionSee the general contract of theskipBytesmethod ofDataInput.Bytes for this operation are read from the contained input stream. - Specified by:
- skipBytesin 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.
 
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readBooleanpublic final boolean readBoolean() throws IOExceptionSee the general contract of thereadBooleanmethod ofDataInput.Bytes for this operation are read from the contained input stream. - Specified by:
- readBooleanin interface- DataInput
- 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:
- FilterInputStream.in
 
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readBytepublic final byte readByte() throws IOExceptionSee the general contract of thereadBytemethod ofDataInput.Bytes for this operation are read from the contained input stream. - Specified by:
- readBytein 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:
- FilterInputStream.in
 
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readUnsignedBytepublic final int readUnsignedByte() throws IOExceptionSee the general contract of thereadUnsignedBytemethod ofDataInput.Bytes for this operation are read from the contained input stream. - Specified by:
- readUnsignedBytein 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:
- FilterInputStream.in
 
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readShortpublic final short readShort() throws IOExceptionSee the general contract of thereadShortmethod ofDataInput.Bytes for this operation are read from the contained input stream. - Specified by:
- readShortin 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:
- FilterInputStream.in
 
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readUnsignedShortpublic final int readUnsignedShort() throws IOExceptionSee the general contract of thereadUnsignedShortmethod ofDataInput.Bytes for this operation are read from the contained input stream. - Specified by:
- readUnsignedShortin 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:
- FilterInputStream.in
 
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readCharpublic final char readChar() throws IOExceptionSee the general contract of thereadCharmethod ofDataInput.Bytes for this operation are read from the contained input stream. - Specified by:
- readCharin 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:
- FilterInputStream.in
 
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readIntpublic final int readInt() throws IOExceptionSee the general contract of thereadIntmethod ofDataInput.Bytes for this operation are read from the contained input stream. - Specified by:
- readIntin 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:
- FilterInputStream.in
 
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readLongpublic final long readLong() throws IOExceptionSee the general contract of thereadLongmethod ofDataInput.Bytes for this operation are read from the contained input stream. - Specified by:
- readLongin 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:
- FilterInputStream.in
 
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readFloatpublic final float readFloat() throws IOExceptionSee the general contract of thereadFloatmethod ofDataInput.Bytes for this operation are read from the contained input stream. - Specified by:
- readFloatin 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:
- readInt(),- Float.intBitsToFloat(int)
 
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readDoublepublic final double readDouble() throws IOExceptionSee the general contract of thereadDoublemethod ofDataInput.Bytes for this operation are read from the contained input stream. - Specified by:
- readDoublein 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:
- readLong(),- Double.longBitsToDouble(long)
 
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readLine@Deprecated public final String readLine() throws IOException 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 interface- DataInput
- Returns:
- the next line of text from this input stream.
- Throws:
- IOException- if an I/O error occurs.
- See Also:
- BufferedReader.readLine(),- FilterInputStream.in
 
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readUTFpublic final String readUTF() throws IOException See the general contract of thereadUTFmethod ofDataInput.Bytes for this operation are read from the contained input stream. - Specified by:
- readUTFin 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(java.io.DataInput)
 
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readUTFpublic static final String readUTF(DataInput in) throws IOException 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:
- readUnsignedShort()
 
 
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