Java NIO: The concept of the channel of the NIO series tutorial in Java

One: Java's NIO channel

Java NiO channels are similar to streams, but are somewhat different:

The ==> can read data from the channel and write data to the channel. But stream reads and writes are usually one-way.

==> channels can be read and written asynchronously.

The data in the ==> channel is always read to a buffer first, or it is always written from a buffer.

As mentioned above, the data is read from the channel to the buffer, and the data is written from the buffer to the channel. As shown in the following:




Second: implementation of the channel of NiO in Java

These are the most important implementations of the channel in Java NIO:

==>filechannel:

==>datagramchannel

==>socketchannel

==>serversocketchannel





Third: The role of the implementation of the Java NIO Channel


==>filechannel Read and write data from a file.

==>datagramchannel can read and write data on the network through UDP.

==>socketchannel can read and write data in the network via TCP.

==>serversocketchannel can listen for incoming TCP connections, like a Web server. A socketchannel is created for each new incoming connection.




Four: A basic example of a Java NIO channel

1  PackageCom.yeepay.sxf.testnio;2 3 Importjava.io.IOException;4 ImportJava.io.RandomAccessFile;5 ImportJava.nio.ByteBuffer;6 ImportJava.nio.channels.FileChannel;7 /**8 * Simple test of the role of channel components in the Java NiO9  * @authorSXFTen  * One  */ A  Public classTestchannelfornio { -  -      Public Static voidMain (string[] args)throwsIOException { the         //loading files into memory/usr/sxf/testnio file -Randomaccessfile Afile =NewRandomaccessfile ("/usr/sxf/testnio", "RW"); -         //get the channel from the file -FileChannel Inchannel =Afile.getchannel (); +         //registers a buffer from the channel, 48 bytes at a time -Bytebuffer buf = Bytebuffer.allocate (48); +         //Read the first time A         intBytesread =Inchannel.read (BUF); at         //See if there's any data in the file -          while(Bytesread! =-1) { -             //print the number of characters that are read for the first time -System.out.println ("Read" +bytesread); -              -             //Note that the call to Buf.flip () first reads the data into buffer, then inverts the buffer, and then reads the data from buffer.  in Buf.flip (); -              to             //print each character to a console +              while(Buf.hasremaining ()) { -System.out.print ((Char) Buf.get ()); the             } *              $             //clear this buffer .Panax Notoginseng buf.clear (); -      theBytesread =Inchannel.read (BUF); +  A         } the  + afile.close (); -     } $}

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Java NIO: The concept of the channel of the NIO series tutorial in Java