Tomcat 7 Connector 精读（1）

这个类图是本人截取的最重要的类的方法和属性。

其中ProtocalHandler是协议处理器，tomcat支持的协议以下方法可以看到。不同协议实现了不同的ProtocalHandler类。

public void setProtocol(String protocol) {

        if (AprLifecycleListener.isAprAvailable()) {
            if ("HTTP/1.1".equals(protocol)) {
                setProtocolHandlerClassName
                    ("org.apache.coyote.http11.Http11AprProtocol");
            } else if ("AJP/1.3".equals(protocol)) {
                setProtocolHandlerClassName
                    ("org.apache.coyote.ajp.AjpAprProtocol");
            } else if (protocol != null) {
                setProtocolHandlerClassName(protocol);
            } else {
                setProtocolHandlerClassName
                    ("org.apache.coyote.http11.Http11AprProtocol");
            }
        } else {
            if ("HTTP/1.1".equals(protocol)) {
                setProtocolHandlerClassName
                    ("org.apache.coyote.http11.Http11NioProtocol");
            } else if ("AJP/1.3".equals(protocol)) {
                setProtocolHandlerClassName
                    ("org.apache.coyote.ajp.AjpNioProtocol");
            } else if (protocol != null) {
                setProtocolHandlerClassName(protocol);
            }
        }

    }

ProtocalHandler是整个Connector类的核心。

初始化Connector的时候;根据协议名字创建处理器对象。

 public Connector(String protocol) {
        setProtocol(protocol);
        // Instantiate protocol handler
        ProtocolHandler p = null;
        try {
            Class<?> clazz = Class.forName(protocolHandlerClassName);
            p = (ProtocolHandler) clazz.newInstance();
        } catch (Exception e) {
            log.error(sm.getString(
                    "coyoteConnector.protocolHandlerInstantiationFailed"), e);
        } finally {
            this.protocolHandler = p;
        }

        if (!Globals.STRICT_SERVLET_COMPLIANCE) {
            URIEncoding = "UTF-8";
            URIEncodingLower = URIEncoding.toLowerCase(Locale.ENGLISH);
        }
    }

首先是初始化协议处理器（去除了不太重要的代码）

protected void initInternal() throws LifecycleException {

        super.initInternal();

        // 初始化Adapter
        adapter = new CoyoteAdapter(this);
        protocolHandler.setAdapter(adapter);
// 每个协议处理器都有对应的适配器，适配器干啥的呢？

         protocolHandler.init();

    }

Connector的启动，实则是启动对应的协议处理器的启动，

 protected void startInternal() throws LifecycleException {

        // Validate settings before starting
        if (getPort() < 0) {
            throw new LifecycleException(sm.getString(
                    "coyoteConnector.invalidPort", Integer.valueOf(getPort())));
        }

        setState(LifecycleState.STARTING);

        try {
            protocolHandler.start();
        } catch (Exception e) {
            String errPrefix = "";
            if(this.service != null) {
                errPrefix += "service.getName(): \"" + this.service.getName() + "\"; ";
            }

            throw new LifecycleException
                (errPrefix + " " + sm.getString
                 ("coyoteConnector.protocolHandlerStartFailed"), e);
        }
    }

终止实则是终止协议处理器

 protected void startInternal() throws LifecycleException {

        // Validate settings before starting
        if (getPort() < 0) {
            throw new LifecycleException(sm.getString(
                    "coyoteConnector.invalidPort", Integer.valueOf(getPort())));
        }

        setState(LifecycleState.STARTING);

        try {
            protocolHandler.start();
        } catch (Exception e) {
            String errPrefix = "";
            if(this.service != null) {
                errPrefix += "service.getName(): \"" + this.service.getName() + "\"; ";
            }

            throw new LifecycleException
                (errPrefix + " " + sm.getString
                 ("coyoteConnector.protocolHandlerStartFailed"), e);
        }
    }

各位看管看到这里，其实看到连接器类需要做如下工作

（1）创建请求对象

/**
     * Create (or allocate) and return a Request object suitable for
     * specifying the contents of a Request to the responsible Container.
     */
    public Request createRequest() {

        Request request = new Request();
        request.setConnector(this);
        return (request);

    }

（2）创建响应对象

  /**
     * Create (or allocate) and return a Response object suitable for
     * receiving the contents of a Response from the responsible Container.
     */
    public Response createResponse() {

        Response response = new Response();
        response.setConnector(this);
        return (response);

    }

（3）传给这两个对象给容器，简单而言，就是在创建好对象后，传递给那个适配器类就OK了。CoyoteAdapter类