| Java | 您所在的位置：网站首页 › 小试身手 › Java |
Java
|
通过之前两篇文章
Java-WebSocket 项目的研究(一) Java-WebSocket类图描述
Java-WebSocket 项目的研究(二) 小试身手：客户端连接服务器并发送消息实例 的介绍我们大概了解到了整个项目的类结构，其中有一个重要的类：WebSocketClient，下面就让我们详细了解一下这个类
首先看一下我们之前的类图关于WebSocketClient的描述，可以看出： 1.继承自WebSocketAdapter 2.依赖于类WebSocketImpl（实际上关于WebSocket核心代码都在类WebSocketImpl里） 3.实现了WebSocket接口（实际上通过类WebSocketImpl实现的）
很简单的，从字面意思我们就大概能猜到WebSocketAdapter是适配器类，架起了WebSocketImpl与WebSocketClient之间的桥梁，WebSocketImpl是web implementation的缩写，意思就是真正实现了websocket里主要的功能。
然后我们看一下WebSocketClient的几个主要方法： 首先是connect方法 [java] view plain copy print ?
/** * Initiates the websocket connection. This method does not block. */ public void connect() { if( writeThread != null ) throw new IllegalStateException( "WebSocketClient objects are not reuseable" ); writeThread = new Thread( this ); writeThread.start(); }
/**
* Initiates the websocket connection. This method does not block.
*/
public void connect() {
if( writeThread != null )
throw new IllegalStateException( "WebSocketClient objects are not reuseable" );
writeThread = new Thread( this );
writeThread.start();
}
我们可以发现：
他其实是起了一个线程，由于WebSocketClient类实现了Runnable接口，因此他会自动去调用run方法，然后我们进一步到run方法里去一探究竟 [java] view plain copy print ?
public void run() { try { if( socket == null ) { socket = new Socket( proxy ); } else if( socket.isClosed() ) { throw new IOException(); } System.out.println("----> "+uri.toString()+" port: "+getPort() ); if( !socket.isBound() ) socket.connect( new InetSocketAddress( uri.getHost(), getPort() ), connectTimeout ); istream = socket.getInputStream(); ostream = socket.getOutputStream(); sendHandshake(); } catch ( /*IOException | SecurityException | UnresolvedAddressException | InvalidHandshakeException | ClosedByInterruptException | SocketTimeoutException */Exception e ) { onWebsocketError( engine, e ); engine.closeConnection( CloseFrame.NEVER_CONNECTED, e.getMessage() ); return; } writeThread = new Thread( new WebsocketWriteThread() ); writeThread.start(); byte[] rawbuffer = new byte[ WebSocketImpl.RCVBUF ]; int readBytes; try { while ( !isClosed() && ( readBytes = istream.read( rawbuffer ) ) != -1 ) { engine.decode( ByteBuffer.wrap( rawbuffer, 0, readBytes ) ); } engine.eot(); } catch ( IOException e ) { engine.eot(); } catch ( RuntimeException e ) { // this catch case covers internal errors only and indicates a bug in this websocket implementation onError( e ); engine.closeConnection( CloseFrame.ABNORMAL_CLOSE, e.getMessage() ); } assert ( socket.isClosed() ); }
public void run() {
try {
if( socket == null ) {
socket = new Socket( proxy );
} else if( socket.isClosed() ) {
throw new IOException();
}
System.out.println("----> "+uri.toString()+" port: "+getPort() );
if( !socket.isBound() )
socket.connect( new InetSocketAddress( uri.getHost(), getPort() ), connectTimeout );
istream = socket.getInputStream();
ostream = socket.getOutputStream();
sendHandshake();
} catch ( /*IOException | SecurityException | UnresolvedAddressException | InvalidHandshakeException | ClosedByInterruptException | SocketTimeoutException */Exception e ) {
onWebsocketError( engine, e );
engine.closeConnection( CloseFrame.NEVER_CONNECTED, e.getMessage() );
return;
}
writeThread = new Thread( new WebsocketWriteThread() );
writeThread.start();
byte[] rawbuffer = new byte[ WebSocketImpl.RCVBUF ];
int readBytes;
try {
while ( !isClosed() && ( readBytes = istream.read( rawbuffer ) ) != -1 ) {
engine.decode( ByteBuffer.wrap( rawbuffer, 0, readBytes ) );
}
engine.eot();
} catch ( IOException e ) {
engine.eot();
} catch ( RuntimeException e ) {
// this catch case covers internal errors only and indicates a bug in this websocket implementation
onError( e );
engine.closeConnection( CloseFrame.ABNORMAL_CLOSE, e.getMessage() );
}
assert ( socket.isClosed() );
}
下面我们对上面的代码进行详细研究： [java] view plain copy print ?
socket = new Socket( proxy );
socket = new Socket( proxy );
这句显而易见，是创建了一个socket套接字。
[java]
view plain
copy
print
?
socket.connect( new InetSocketAddress( uri.getHost(), getPort() ), connectTimeout );
socket.connect( new InetSocketAddress( uri.getHost(), getPort() ), connectTimeout );
这句的意思是创建连接，参数就是服务器地址，端口号，超时时间。
[java]
view plain
copy
print
?
istream = socket.getInputStream();
istream = socket.getInputStream();
是接受服务器端的数据，关于接受的详细过程，我会在后期的博客中阐述，敬请期待。
[java]
view plain
copy
print
?
ostream = socket.getOutputStream();
ostream = socket.getOutputStream();
是发送数据用的。
其他的先不解释，我们继续之前的流程------connect之后就要发送信息，也就是调用send方法，send方法如下： [java] view plain copy print ?
/** * Sends text to the connected websocket server. * * @param text * The string which will be transmitted. */ public void send( String text ) throws NotYetConnectedException { engine.send( text ); }
/**
* Sends text to the connected websocket server.
*
* @param text
* The string which will be transmitted.
*/
public void send( String text ) throws NotYetConnectedException {
engine.send( text );
}
它调用了engine的send方法，那么engine是啥东东呢，在类的声明处有这么一句话：
[java]
view plain
copy
print
?
private WebSocketImpl engine = null;
private WebSocketImpl engine = null;
说明了
WebSocketImpl类实现了send的操作。
转自：http://blog.csdn.net/zjh171/article/details/24800493 |
【本文地址】
公司简介
联系我们