Java中channel用法總結

本文實例總結了Java中channel用法。分享給大家供大家參考。具體分析如下：

1.Channel接口的定義：

 public interface Channel{ public boolean isOpen( ); public void close( ) throws IOException;}

2.Channel的常見類型：

FileChannel, SocketChannel, ServerSocketChannel, and DatagramChannel；
FileChannel通過RandomAccessFile, FileInputStream, FileOutputStream的getChannel()來初始化。

 SocketChannel sc = SocketChannel.open();sc.connect (new InetSocketAddress ("somehost", someport));ServerSocketChannel ssc = ServerSocketChannel.open( );ssc.socket().bind (new InetSocketAddress (somelocalport));DatagramChannel dc = DatagramChannel.open();

3.Scatter/Gather，必須使用ByteBuffer.allocateDirect(100)

 public interface ScatteringByteChannel extends ReadableByteChannel { public long read (ByteBuffer [] dsts) throws IOException; public long read (ByteBuffer [] dsts, int offset, int length) throws IOException;}public interface GatheringByteChannel extends WritableByteChannel { public long write(ByteBuffer[] srcs) throws IOException; public long write(ByteBuffer[] srcs, int offset, int length) throws IOException;}

4.file lock是和file相關，而不是channel。可以對進程有效，而不是線程。可以通過內存映射文件(memory-mapped file)來實現線程同步

5.buffer = fileChannel.map (FileChannel.MapMode.READ_ONLY, 100, 200);

6.MappedByteBuffer are direct. load( )將整個文件加載到內存（改方法不能保證完成）。 force( )將數據flush到硬盤。

7.未綁定端口的DatagramChannel系統會自動分配端口。 DatagramChannel的connect()，將保證只接受指定源地址的數據包。這時候，可以使用普通的read和write方法，包括Scatter/Gather

希望本文所述對大家的java程序設計有所幫助。