类继承图
1.接口Channel
2.抽象类
服务器端ServerSocketChannel和客户端SocketChannel
与socket平级的通道还有本地磁盘文件file 网络套接字socket device 内存等。也就是说 通道不止一种 其中有包括了套接字socket。nio包的channel只是把不同硬件设备(网络编程-网卡 磁盘文件 内存)的读写方式 统一成了通道这么一个概念。具体来说 就是 不同通道都继承了Channel这个接口。
3.实现可
服务器端ServerSocketChannelImpl和客户端SocketChannelImpl
file:///var/folders/m9/yshd99dx1g38gtyxvv3k201r0000gn/T/WizNote/66d37a06-db36-4885-97c7-d3a782a18a83/index_files/d6d53fd2-73fb-4416-a4a4-8f0e8bdd3bdb.jpg
file:///var/folders/m9/yshd99dx1g38gtyxvv3k201r0000gn/T/WizNote/66d37a06-db36-4885-97c7-d3a782a18a83/index_files/39568da6-b31d-491d-bdfe-b6e4d4eae272.jpg
服务器端
主要方法
1.bind()
2.listen()
3.accept()方法 //接受客户端的连接
4.读写数据
时序图
file:///var/folders/m9/yshd99dx1g38gtyxvv3k201r0000gn/T/WizNote/66d37a06-db36-4885-97c7-d3a782a18a83/index_files/02a75fd2-efa3-4b2b-ba48-92a5e7f8353d.png
//流程图
源码分析
ServerSocketChannelImpl
/**
* An implementation of ServerSocketChannels
*/
class ServerSocketChannelImpl
extends ServerSocketChannel
implements SelChImpl
{
// Our socket adaptor, if any
ServerSocket socket; //这里虽然包含了
public ServerSocket socket() {
synchronized (stateLock) {
if (socket == null)
socket = ServerSocketAdaptor.create(this);
return socket;
}
}
@Override
public ServerSocketChannel bind(SocketAddress local, int backlog) throws IOException {
synchronized (lock) {
if (!isOpen())
throw new ClosedChannelException();
if (isBound())
throw new AlreadyBoundException();
InetSocketAddress isa = (local == null) ? new InetSocketAddress(0) :
Net.checkAddress(local);
SecurityManager sm = System.getSecurityManager();
if (sm != null)
sm.checkListen(isa.getPort());
NetHooks.beforeTcpBind(fd, isa.getAddress(), isa.getPort());
Net.bind(fd, isa.getAddress(), isa.getPort()); //native方法
Net.listen(fd, backlog < 1 ? 50 : backlog); //native方法
synchronized (stateLock) {
localAddress = Net.localAddress(fd);
}
}
return this;
}
public class ServerSocketAdaptor // package-private
extends ServerSocket
{
// The channel being adapted
private final ServerSocketChannelImpl ssc;
public void bind(SocketAddress local, int backlog) throws IOException {
if (local == null)
local = new InetSocketAddress(0);
try {
ssc.bind(local, backlog); //最终还是调用ServerSocketChannelImpl.bind()
} catch (Exception x) {
Net.translateException(x);
}
}
ServerSocketChannel
/**
* A selectable channel for stream-oriented listening sockets.
*
* <p> A server-socket channel is created by invoking the {@link #open() open}
* method of this class. It is not possible to create a channel for an arbitrary,
* pre-existing {@link ServerSocket}. A newly-created server-socket channel is
* open but not yet bound. An attempt to invoke the {@link #accept() accept}
* method of an unbound server-socket channel will cause a {@link NotYetBoundException}
* to be thrown. A server-socket channel can be bound by invoking one of the
* {@link #bind(java.net.SocketAddress,int) bind} methods defined by this class.
*
* <p> Socket options are configured using the {@link #setOption(SocketOption,Object)
* setOption} method. Server-socket channels support the following options:
* <blockquote>
* <table border summary="Socket options">
* <tr>
* <th>Option Name</th>
* <th>Description</th>
* </tr>
* <tr>
* <td> {@link java.net.StandardSocketOptions#SO_RCVBUF SO_RCVBUF} </td>
* <td> The size of the socket receive buffer </td>
* </tr>
* <tr>
* <td> {@link java.net.StandardSocketOptions#SO_REUSEADDR SO_REUSEADDR} </td>
* <td> Re-use address </td>
* </tr>
* </table>
* </blockquote>
* Additional (implementation specific) options may also be supported.
*
* <p> Server-socket channels are safe for use by multiple concurrent threads.
* </p>
*
* @author Mark Reinhold
* @author JSR-51 Expert Group
* @since 1.4
*/
public abstract class ServerSocketChannel
extends AbstractSelectableChannel
implements NetworkChannel
{
public abstract class SelectableChannel
extends AbstractInterruptibleChannel
implements Channel
{
客户端
主要方法
1.connect()方法 //连接服务器端
2.读写数据
