readUTF method of DataInput. Bytes for this operation are read from the contained input stream. @return a Unicode string. @exception EOFException if this input stream reaches the end beforereading all the bytes. @exception IOException the stream has been closed and the containedinput stream does not support reading after close, or another I/O error occurs. @exception UTFDataFormatException if the bytes do not represent a validmodified UTF-8 encoding of a string. @see java.io.DataInputStream#readUTF(java.io.DataInput)
ObjectOutputStream.writeUTF()
@throws IOException If an IO exception happened when reading the primitive data.
readUTF is that it reads a representation of a Unicode character string encoded in modified UTF-8 format; this string of characters is then returned as a String. First, two bytes are read and used to construct an unsigned 16-bit integer in the manner of the readUnsignedShort method, using network byte order (regardless of the current byte order setting). This integer value is called the UTF length and specifies the number of additional bytes to be read. These bytes are then converted to characters by considering them in groups. The length of each group is computed from the value of the first byte of the group. The byte following a group, if any, is the first byte of the next group.
If the first byte of a group matches the bit pattern 0xxxxxxx (where x means "may be 0 or 1"), then the group consists of just that byte. The byte is zero-extended to form a character.
If the first byte of a group matches the bit pattern 110xxxxx, then the group consists of that byte a and a second byte b. If there is no byte b (because byte a was the last of the bytes to be read), or if byte b does not match the bit pattern 10xxxxxx, then a UTFDataFormatException is thrown. Otherwise, the group is converted to the character:
(char)(((a& 0x1F) << 6) | (b & 0x3F)) 1110xxxx, then the group consists of that byte a and two more bytes b and c. If there is no byte c (because byte a was one of the last two of the bytes to be read), or either byte b or byte c does not match the bit pattern 10xxxxxx, then a UTFDataFormatException is thrown. Otherwise, the group is converted to the character:
(char)(((a & 0x0F) << 12) | ((b & 0x3F) << 6) | (c & 0x3F)) 1111xxxx or the pattern 10xxxxxx, then a UTFDataFormatException is thrown. If end of file is encountered at any time during this entire process, then an java.io.EOFException is thrown.
After every group has been converted to a character by this process, the characters are gathered, in the same order in which their corresponding groups were read from the input stream, to form a String, which is returned.
The current byte order setting is ignored.
The bit offset within the stream is reset to zero before the read occurs.
Note: This method should not be used in the implementation of image formats that use standard UTF-8, because the modified UTF-8 used here is incompatible with standard UTF-8. @return a String read from the stream. @exception java.io.EOFException if this stream reaches the endbefore reading all the bytes. @exception java.io.UTFDataFormatException if the bytes do not representa valid modified UTF-8 encoding of a string. @exception IOException if an I/O error occurs.
For more information on the UTF-8 format, see "File System Safe UCS Transformation Format (FSS_UTF)", X/Open Preliminary Specification, X/Open Company Ltd., Document Number: P316. This information also appears in ISO/IEC 10646, Annex P. @return a Unicode string from the bytes message stream @throws JMSException if the JMS provider fails to read the message due to some internal error. @throws MessageEOFException if unexpected end of bytes stream has been reached. @throws MessageNotReadableException if the message is in write-only mode.
For more information on the UTF-8 format, see "File System Safe UCS Transformation Format (FSS_UTF)", X/Open Preliminary Specification, X/Open Company Ltd., Document Number: P316. This information also appears in ISO/IEC 10646, Annex P. @return a Unicode string from the bytes message stream @throws JMSException if the JMS provider fails to read the message due tosome internal error. @throws MessageEOFException if unexpected end of bytes stream has beenreached. @throws MessageNotReadableException if the message is in write-only mode.
For more information on the UTF-8 format, see "File System Safe UCS Transformation Format (FSS_UTF)", X/Open Preliminary Specification, X/Open Company Ltd., Document Number: P316. This information also appears in ISO/IEC 10646, Annex P. @return a Unicode string from the bytes message stream @throws JMSException if the JMS provider fails to read the message due to some internal error. @throws MessageEOFException if unexpected end of bytes stream has been reached. @throws MessageNotReadableException if the message is in write-only mode.
DataInput The length of the string has been encoded by the {@link DataOutput}, so no length needs to be given as parameter.
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