Streams - Java Network Programming - page 43

strings. For exchanging UTF-8 text with all other software, you should use an Input
StreamReader with the appropriate encoding. (There wouldn't be any confusion if Sun
had just called this method and its partner writeString() and readString() rather
than writeUTF() and readUTF() .)
Along with these methods for writing binary numbers and strings, DataOutput
Stream of course has the usual write() , flush() , and close() methods any Output
Stream class has.
DataInputStream is the complementary class to DataOutputStream . Every format that
DataOutputStream writes, DataInputStream can read. In addition, DataInputStream
has the usual read() , available() , skip() , and close() methods, as well as methods
for reading complete arrays of bytes and lines of text.
There are 9 methods to read binary data that match the 11 methods in DataOutput
Stream (there's no exact complement for writeBytes() or writeChars() ; these are
handled by reading the bytes and chars one at a time):
public final boolean readBoolean () throws IOException
public final byte readByte () throws IOException
public final char readChar () throws IOException
public final short readShort () throws IOException
public final int readInt () throws IOException
public final long readLong () throws IOException
public final float readFloat () throws IOException
public final double readDouble () throws IOException
public final String readUTF () throws IOException
In addition, DataInputStream provides two methods to read unsigned bytes and un‐
signed shorts and return the equivalent int . Java doesn't have either of these data types,
but you may encounter them when reading binary data written by a C program:
public final int readUnsignedByte () throws IOException
public final int readUnsignedShort () throws IOException
DataInputStream has the usual two multibyte read() methods that read data into an
array or subarray and return the number of bytes read. It also has two readFully()
methods that repeatedly read data from the underlying input stream into an array until
the requested number of bytes have been read. If enough data cannot be read, then an
IOException is thrown. These methods are especially useful when you know in advance
exactly how many bytes you have to read. This might be the case when you've read the
Content-length field out of an HTTP header and thus know how many bytes of data
there are:
public final int read ( byte [] input ) throws IOException
public final int read ( byte [] input , int offset , int length )
throws IOException
public final void readFully ( byte [] input ) throws IOException