tomcat源码分析 JIoEndpoint SocketProcessor处理过程

当JIoEndpoint接受到请求时，生成SocketProcessor实例，SocketProcessor实现了Runnable接口。

我们稍微看一下SocketProcessor的run方法做了什么事情。

1、设置SocketState状态为SocketState.OPEN，这是一个枚举类。

SocketState state = SocketState.OPEN;

2、对socket进行一些额外处理，事实上只有在ssl的情况下，才会有额外处理。

如抛出异常，则设置状态值为SocketState.CLOSED

// SSL handshake
serverSocketFactory.handshake(socket.getSocket());

3、刚开始接收到请求时处理

if ((state != SocketState.CLOSED)) {
if (status == null) {
state = handler.process(socket, SocketStatus.OPEN);
} else {
state = handler.process(socket,status);
}
}

4、交由org.apache.coyote.http11.Http11Protocol.Http11ConnectionHandler 来处理socket请求

　Http11ConnectionHandler 会先获取一个Http11Processor实例，如有必要，创建一个。

然后根据当前状态，选择Http11Processor相应方式来处理socket。

do {
if (status == SocketStatus.DISCONNECT &&
!processor.isComet()) {
// Do nothing here, just wait for it to get recycled
// Don't do this for Comet we need to generate an end
// event (see BZ 54022)
} else if (processor.isAsync() ||
state == SocketState.ASYNC_END) {
state = processor.asyncDispatch(status);
} else if (processor.isComet()) {
state = processor.event(status);
} else if (processor.isUpgrade()) {
state = processor.upgradeDispatch();
} else {
state = processor.process(socket);
}

if (state != SocketState.CLOSED && processor.isAsync()) {
state = processor.asyncPostProcess();
}

if (state == SocketState.UPGRADING) {
// Get the UpgradeInbound handler
UpgradeInbound inbound = processor.getUpgradeInbound();
// Release the Http11 processor to be re-used
release(socket, processor, false, false);
// Create the light-weight upgrade processor
processor = createUpgradeProcessor(socket, inbound);
inbound.onUpgradeComplete();
}
} while (state == SocketState.ASYNC_END ||
state == SocketState.UPGRADING);

当跳出循环之后，再根据状态值选择release还是longPoll

release收回Http11Processor实例，longPoll则将以socket为key, processor为值放对map中，以做下一步处理。

5、再根据handler的处理结果，来决定下一步的处理。

录为OPEN, UPGRADING, UPGRADED时，则设置launch=true。

if (state == SocketState.OPEN ||
state == SocketState.UPGRADING  ||
state == SocketState.UPGRADED){
socket.setKeptAlive(true);
socket.access();
launch = true;
}

6、当状态为LONG，则表示连接还持续，请求还需要再处理。类似于文件上传的这类请求。

if (state == SocketState.LONG) {
socket.access();
waitingRequests.add(socket);
}

7、最终进入finally代码块

当状态为lauch，则需要进一步处理请求。

if (launch) {
try {
getExecutor().execute(new SocketProcessor(socket, SocketStatus.OPEN));
} catch (RejectedExecutionException x) {
///.......
}
}