tomcat源码分析 Acceptor run 过程

org.apache.tomcat.util.net.JIoEndpoint.Acceptor

1、调用countUpOrAwaitConnection，阀门数加1。

     每个Acceptor有最大处理上限，默认为10000，如为-1，则无上限。

     

protected void countUpOrAwaitConnection() throws InterruptedException {
        if (maxConnections==-1) return;
        LimitLatch latch = connectionLimitLatch;
        if (latch!=null) latch.countUpOrAwait();
    }

2、默认serverSocket监听8080端口，当监听到请求时，为socket设置默认的options。

protected boolean setSocketOptions(Socket socket) {
        try {
            // 1: Set socket options: timeout, linger, etc
            socketProperties.setProperties(socket);
        } catch (SocketException s) {
            //error here is common if the client has reset the connection
            if (log.isDebugEnabled()) {
                log.debug(sm.getString("endpoint.err.unexpected"), s);
            }
            // Close the socket
            return false;
        } catch (Throwable t) {
            ExceptionUtils.handleThrowable(t);
            log.error(sm.getString("endpoint.err.unexpected"), t);
            // Close the socket
            return false;
        }
        return true;
    }

3、为其生成一个包装器类，SocketWrapper，除socket属性之外，还包括其它一些属性

    如：lastAccess， timeout，async

4、为包装器类生成一个SocketProcessor类，这个类实现了Runnable接口，并将此实例添加到线程队列中，交由线程池处理。

protected boolean processSocket(Socket socket) {
        // Process the request from this socket
        try {
            SocketWrapper<Socket> wrapper = new SocketWrapper<Socket>(socket);
            wrapper.setKeepAliveLeft(getMaxKeepAliveRequests());
            // During shutdown, executor may be null - avoid NPE
            if (!running) {
                return false;
            }
            getExecutor().execute(new SocketProcessor(wrapper));
        } catch (RejectedExecutionException x) {
            log.warn("Socket processing request was rejected for:"+socket,x);
            return false;
        } catch (Throwable t) {
            ExceptionUtils.handleThrowable(t);
            // This means we got an OOM or similar creating a thread, or that
            // the pool and its queue are full
            log.error(sm.getString("endpoint.process.fail"), t);
            return false;
        }
        return true;
    }

5、阀门数减1.

protected long countDownConnection() {
        if (maxConnections==-1) return -1;
        LimitLatch latch = connectionLimitLatch;
        if (latch!=null) {
            long result = latch.countDown();
            if (result<0) {
                getLog().warn("Incorrect connection count, multiple socket.close called on the same socket." );
            }
            return result;
        } else return -1;
    }