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.
DataOutputStreamin public DataInputStream(InputStream in)
Creates a DataInputStream that uses the specified underlying InputStream.
in - the specified input streampublic 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)
read in class FilterInputStream
b - the buffer into which the data is read.-1 if there is no more data because the end of the stream has been reached.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.FilterInputStream.in, InputStream.read(byte[], int, int)
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.
read in class FilterInputStream
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.-1 if there is no more data because the end of the stream has been reached.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.FilterInputStream.in, InputStream.read(byte[], int, int)
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.
readFully in interface DataInput
b - the buffer into which the data is read.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.FilterInputStream.inpublic 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.
readFully in interface DataInput
b - the buffer into which the data is read.off - the start offset of the data.len - the number of bytes to read.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.FilterInputStream.inpublic 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.
skipBytes in interface DataInput
n - the number of bytes to be skipped.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.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.
readBoolean in interface DataInput
boolean value read.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.FilterInputStream.inpublic 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.
readByte in interface DataInput
byte.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.FilterInputStream.inpublic 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.
readUnsignedByte in interface DataInput
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.FilterInputStream.inpublic 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.
readShort in interface DataInput
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.FilterInputStream.inpublic 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.
readUnsignedShort in interface DataInput
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.FilterInputStream.inpublic 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.
readChar in interface DataInput
char.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.FilterInputStream.inpublic 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.
readInt in interface DataInput
int.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.FilterInputStream.inpublic 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.
readLong in interface DataInput
long.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.FilterInputStream.inpublic 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.
readFloat in interface DataInput
float.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.readInt(), Float.intBitsToFloat(int)
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.
readDouble in interface DataInput
double.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.readLong(), Double.longBitsToDouble(long)
@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 the BufferedReader.readLine() method. Programs that use the DataInputStream class to read lines can be converted to use the BufferedReader class by replacing code of the form:
DataInputStream d = new DataInputStream(in);with:
BufferedReader d
= new BufferedReader(new InputStreamReader(in)); See the general contract of the readLine method of DataInput.
Bytes for this operation are read from the contained input stream.
readLine in interface DataInput
IOException - if an I/O error occurs.BufferedReader.readLine(), FilterInputStream.in
public final String readUTF()
throws IOException See the general contract of the readUTF method of DataInput.
Bytes for this operation are read from the contained input stream.
readUTF in interface DataInput
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.readUTF(java.io.DataInput)public static final String readUTF(DataInput in)
throws IOException 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.
in - a data input stream.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.readUnsignedShort()
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