Java中channel用法總結_java

本文執行個體總結了Java中channel用法。分享給大家供大家參考。具體分析如下：

1.Channel介面的定義：

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。可以通過記憶體對應檔(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( )將整個檔案載入到記憶體（改方法不能保證完成）。force( )將資料flush到硬碟。

7.未綁定連接埠的DatagramChannel系統會自動分配連接埠。DatagramChannel的connect()，將保證只接受指定源地址的資料包。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程式設計有所協助。