Java compact1, compact2, compact3 java.io Class BufferedReader（JDK8）

Constructor Detail

• BufferedReader

  public BufferedReader(Reader in,
                        int sz)

  Creates a buffering character-input stream that uses an input buffer of the specified size.

  Parameters:

  in - A Reader

  sz - Input-buffer size

  Throws:

  IllegalArgumentException - If sz <= 0

• BufferedReader

  public BufferedReader(Reader in)

  Creates a buffering character-input stream that uses a default-sized input buffer.

  Parameters:

  in - A Reader

Method Detail

• read

  public int read()
           throws IOException

  Reads a single character.

  Overrides:

  read in class Reader

  Returns:

  The character read, as an integer in the range 0 to 65535 (0x00-0xffff), or -1 if the end of the stream has been reached

  Throws:

  IOException - If an I/O error occurs

• read

  public int read(char[] cbuf,
                  int off,
                  int len)
           throws IOException

  Reads characters into a portion of an array.

  This method implements the general contract of the corresponding read method of the Reader class. As an additional convenience, it attempts to read as many characters as possible by repeatedly invoking the read method of the underlying stream. This iterated read continues until one of the following conditions becomes true:

  • The specified number of characters have been read,
  • The read method of the underlying stream returns -1, indicating end-of-file, or
  • The ready method of the underlying stream returns false, indicating that further input requests would block.

  If the first read on the underlying stream returns -1 to 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. Thus redundant BufferedReaders will not copy data unnecessarily.

  Specified by:

  read in class Reader

  Parameters:

  cbuf - Destination buffer

  off - Offset at which to start storing characters

  len - Maximum number of characters to read

  Returns:

  The number of characters read, or -1 if the end of the stream has been reached

  Throws:

  IOException - If an I/O error occurs

• readLine

  public String readLine()
                  throws IOException

  Reads a line of text. A line is considered to be terminated by any one of a line feed ('\n'), a carriage return ('\r'), or a carriage return followed immediately by a linefeed.

  Returns:

  A String containing the contents of the line, not including any line-termination characters, or null if the end of the stream has been reached

  Throws:

  IOException - If an I/O error occurs

  See Also:

  Files.readAllLines(java.nio.file.Path, java.nio.charset.Charset)

• skip

  public long skip(long n)
            throws IOException

  Skips characters.

  Overrides:

  skip in class Reader

  Parameters:

  n - The number of characters to skip

  Returns:

  The number of characters actually skipped

  Throws:

  IllegalArgumentException - If n is negative.

  IOException - If an I/O error occurs

• ready

  public boolean ready()
                throws IOException

  Tells whether this stream is ready to be read. A buffered character stream is ready if the buffer is not empty, or if the underlying character stream is ready.

  Overrides:

  ready in class Reader

  Returns:

  True if the next read() is guaranteed not to block for input, false otherwise. Note that returning false does not guarantee that the next read will block.

  Throws:

  IOException - If an I/O error occurs

• markSupported

  public boolean markSupported()

  Tells whether this stream supports the mark() operation, which it does.

  Overrides:

  markSupported in class Reader

  Returns:

  true if and only if this stream supports the mark operation.

• mark

  public void mark(int readAheadLimit)
            throws IOException

  Marks the present position in the stream. Subsequent calls to reset() will attempt to reposition the stream to this point.

  Overrides:

  mark in class Reader

  Parameters:

  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.

  Throws:

  IllegalArgumentException - If readAheadLimit < 0

  IOException - If an I/O error occurs

• reset

  public void reset()
             throws IOException

  Resets the stream to the most recent mark.

  Overrides:

  reset in class Reader

  Throws:

  IOException - If the stream has never been marked, or if the mark has been invalidated

• close

  public void close()
             throws IOException

  Description copied from class: Reader
  Closes the stream and releases any system resources associated with it. Once the stream has been closed, further read(), ready(), mark(), reset(), or skip() invocations will throw an IOException. Closing a previously closed stream has no effect.

  Specified by:

  close in interface Closeable

  Specified by:

  close in interface AutoCloseable

  Specified by:

  close in class Reader

  Throws:

  IOException - If an I/O error occurs

• lines

  public Stream<String> lines()

  Returns a Stream, the elements of which are lines read from this BufferedReader. The Stream is 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.

  If an IOException is thrown when accessing the underlying BufferedReader, it is wrapped in an UncheckedIOException which will be thrown from the Stream 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.

  Returns:

  a Stream<String> providing the lines of text described by this BufferedReader

  Since:

  1.8