public class BufferedReader extends Reader
The buffer size may be specified, or the default size may be used. The default is large enough for most purposes.
In general, each read request made of a Reader causes a corresponding read request to be made of the underlying character or byte stream. It is therefore advisable to wrap a BufferedReader around any Reader whose read() operations may be costly, such as FileReaders and InputStreamReaders. For example,
BufferedReader in = new BufferedReader(new FileReader("foo.in"));will buffer the input from the specified file. Without buffering, each invocation of read() or readLine() could cause bytes to be read from the file, converted into characters, and then returned, which can be very inefficient.
Programs that use DataInputStreams for textual input can be localized by replacing each DataInputStream with an appropriate BufferedReader.
|Constructor and Description|
Creates a buffering character-input stream that uses a default-sized input buffer.
Creates a buffering character-input stream that uses an input buffer of the specified size.
|Modifier and Type||Method and Description|
Closes the stream and releases any system resources associated with it.
Marks the present position in the stream.
Tells whether this stream supports the mark() operation, which it does.
Reads a single character.
Reads characters into a portion of an array.
Reads a line of text.
Tells whether this stream is ready to be read.
Resets the stream to the most recent mark.
public BufferedReader(Reader in, int sz)
in- A Reader
sz- Input-buffer size
sz <= 0
public BufferedReader(Reader in)
in- A Reader
public int read() throws IOException
public int read(char cbuf, int off, int len) throws IOException
This method implements the general contract of the corresponding
method of the
class. As an additional convenience, it
attempts to read as many characters as possible by repeatedly invoking
read method of the underlying stream. This iterated
read continues until one of the following conditions becomes
readmethod of the underlying stream returns
-1, indicating end-of-file, or
readymethod of the underlying stream returns
false, indicating that further input requests would block.
readon the underlying stream returns
-1to indicate end-of-file then this method returns
-1. Otherwise this method returns the number of characters actually read.
Subclasses of this class are encouraged, but not required, to attempt to read as many characters as possible in the same fashion.
Ordinarily this method takes characters from this stream's character
buffer, filling it from the underlying stream as necessary. If,
however, the buffer is empty, the mark is not valid, and the requested
length is at least as large as the buffer, then this method will read
characters directly from the underlying stream into the given array.
BufferedReaders will not copy data
public String readLine() throws IOException
IOException- If an I/O error occurs
public long skip(long n) throws IOException
public boolean ready() throws IOException
public boolean markSupported()
public void mark(int readAheadLimit) throws IOException
readAheadLimit- Limit on the number of characters that may be read while still preserving the mark. An attempt to reset the stream after reading characters up to this limit or beyond may fail. A limit value larger than the size of the input buffer will cause a new buffer to be allocated whose size is no smaller than limit. Therefore large values should be used with care.
readAheadLimit < 0
IOException- If an I/O error occurs
public void reset() throws IOException
public void close() throws IOException
Stream, the elements of which are lines read from this
Streamis lazily populated, i.e., read only occurs during the terminal stream operation.
The reader must not be operated on during the execution of the terminal stream operation. Otherwise, the result of the terminal stream operation is undefined.
After execution of the terminal stream operation there are no guarantees that the reader will be at a specific position from which to read the next character or line.
IOException is thrown when accessing the underlying
BufferedReader, it is wrapped in an
UncheckedIOException which will be thrown from the
method that caused the read to take place. This method will return a
Stream if invoked on a BufferedReader that is closed. Any operation on
that stream that requires reading from the BufferedReader after it is
closed, will cause an UncheckedIOException to be thrown.
Stream<String>providing the lines of text described by this
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For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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