Tomcat源码---请求处理四(1)

noel0217

　　一,现在到了StandardWrapperValve#invoke下,现在才算是真正的调用,主要实现了对servlet,filter执行

/**
* Invoke the servlet we are managing, respecting the rules regarding
* servlet lifecycle and SingleThreadModel support.
*
* @param request Request to be processed
* @param response Response to be produced
* @param valveContext Valve context used to forward to the next Valve
*
* @exception IOException if an input/output error occurred
* @exception ServletException if a servlet error occurred
*/
public final void invoke(Request request, Response response)
throws IOException, ServletException {
// Initialize local variables we may need
boolean unavailable = false;
Throwable throwable = null;
// This should be a Request attribute...
long t1=System.currentTimeMillis();
requestCount++;
StandardWrapper wrapper = (StandardWrapper) getContainer();
Servlet servlet = null;
Context context = (Context) wrapper.getParent();
// Check for the application being marked unavailable
if (!context.getAvailable()) {
response.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE,
sm.getString("standardContext.isUnavailable"));
unavailable = true;
}
// Check for the servlet being marked unavailable
if (!unavailable && wrapper.isUnavailable()) {
container.getLogger().info(sm.getString("standardWrapper.isUnavailable",
wrapper.getName()));
long available = wrapper.getAvailable();
if ((available > 0L) && (available < Long.MAX_VALUE)) {
response.setDateHeader("Retry-After", available);
response.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE,
sm.getString("standardWrapper.isUnavailable",
wrapper.getName()));
} else if (available == Long.MAX_VALUE) {
response.sendError(HttpServletResponse.SC_NOT_FOUND,
sm.getString("standardWrapper.notFound",
wrapper.getName()));
}
unavailable = true;
}
// Allocate a servlet instance to process this request
try {
if (!unavailable) {
//servlet行行在这一步
servlet = wrapper.allocate();
}
} catch (UnavailableException e) {
container.getLogger().error(
sm.getString("standardWrapper.allocateException",
wrapper.getName()), e);
long available = wrapper.getAvailable();
if ((available > 0L) && (available < Long.MAX_VALUE)) {
response.setDateHeader("Retry-After", available);
response.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE,
sm.getString("standardWrapper.isUnavailable",
wrapper.getName()));
} else if (available == Long.MAX_VALUE) {
response.sendError(HttpServletResponse.SC_NOT_FOUND,
sm.getString("standardWrapper.notFound",
wrapper.getName()));
}
} catch (ServletException e) {
container.getLogger().error(sm.getString("standardWrapper.allocateException",
wrapper.getName()), StandardWrapper.getRootCause(e));
throwable = e;
exception(request, response, e);
servlet = null;
} catch (Throwable e) {
container.getLogger().error(sm.getString("standardWrapper.allocateException",
wrapper.getName()), e);
throwable = e;
exception(request, response, e);
servlet = null;
}
// Identify if the request is Comet related now that the servlet has been allocated
boolean comet = false;
if (servlet instanceof CometProcessor
&& request.getAttribute("org.apache.tomcat.comet.support") == Boolean.TRUE) {
comet = true;
request.setComet(true);
}
// Acknowledge the request
try {
//通知request已经调用
response.sendAcknowledgement();
} catch (IOException e) {
request.removeAttribute(Globals.JSP_FILE_ATTR);
container.getLogger().warn(sm.getString("standardWrapper.acknowledgeException",
wrapper.getName()), e);
throwable = e;
exception(request, response, e);
} catch (Throwable e) {
container.getLogger().error(sm.getString("standardWrapper.acknowledgeException",
wrapper.getName()), e);
throwable = e;
exception(request, response, e);
servlet = null;
}
MessageBytes requestPathMB = null;
if (request != null) {
requestPathMB = request.getRequestPathMB();
}
request.setAttribute
(ApplicationFilterFactory.DISPATCHER_TYPE_ATTR,
ApplicationFilterFactory.REQUEST_INTEGER);
request.setAttribute
(ApplicationFilterFactory.DISPATCHER_REQUEST_PATH_ATTR,
requestPathMB);
// Create the filter chain for this request
ApplicationFilterFactory factory =
ApplicationFilterFactory.getInstance();
//过滤链的创建
ApplicationFilterChain filterChain =
factory.createFilterChain(request, wrapper, servlet);
// Reset comet flag value after creating the filter chain
request.setComet(false);
// Call the filter chain for this request
// NOTE: This also calls the servlet's service() method
try {
String jspFile = wrapper.getJspFile();
if (jspFile != null)
request.setAttribute(Globals.JSP_FILE_ATTR, jspFile);
else
request.removeAttribute(Globals.JSP_FILE_ATTR);
if ((servlet != null) && (filterChain != null)) {
// Swallow output if needed
if (context.getSwallowOutput()) {
try {
SystemLogHandler.startCapture();
if (comet) {
filterChain.doFilterEvent(request.getEvent());
request.setComet(true);
} else {
//这里面开始对过滤器进行处理
filterChain.doFilter(request.getRequest(),
response.getResponse());
}
} finally {
String log = SystemLogHandler.stopCapture();
if (log != null && log.length() > 0) {
context.getLogger().info(log);
}
}
} else {
if (comet) {
request.setComet(true);
filterChain.doFilterEvent(request.getEvent());
} else {
filterChain.doFilter
(request.getRequest(), response.getResponse());
}
}
}
request.removeAttribute(Globals.JSP_FILE_ATTR);
} catch (ClientAbortException e) {
request.removeAttribute(Globals.JSP_FILE_ATTR);
throwable = e;
exception(request, response, e);
} catch (IOException e) {
request.removeAttribute(Globals.JSP_FILE_ATTR);
container.getLogger().error(sm.getString("standardWrapper.serviceException",
wrapper.getName()), e);
throwable = e;
exception(request, response, e);
} catch (UnavailableException e) {
request.removeAttribute(Globals.JSP_FILE_ATTR);
container.getLogger().error(sm.getString("standardWrapper.serviceException",
wrapper.getName()), e);
//            throwable = e;
//            exception(request, response, e);
wrapper.unavailable(e);
long available = wrapper.getAvailable();
if ((available > 0L) && (available < Long.MAX_VALUE)) {
response.setDateHeader("Retry-After", available);
response.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE,
sm.getString("standardWrapper.isUnavailable",
wrapper.getName()));
} else if (available == Long.MAX_VALUE) {
response.sendError(HttpServletResponse.SC_NOT_FOUND,
sm.getString("standardWrapper.notFound",
wrapper.getName()));
}
// Do not save exception in 'throwable', because we
// do not want to do exception(request, response, e) processing
} catch (ServletException e) {
request.removeAttribute(Globals.JSP_FILE_ATTR);
Throwable rootCause = StandardWrapper.getRootCause(e);
if (!(rootCause instanceof ClientAbortException)) {
container.getLogger().error(sm.getString("standardWrapper.serviceException",
wrapper.getName()), rootCause);
}
throwable = e;
exception(request, response, e);
} catch (Throwable e) {
request.removeAttribute(Globals.JSP_FILE_ATTR);
container.getLogger().error(sm.getString("standardWrapper.serviceException",
wrapper.getName()), e);
throwable = e;
exception(request, response, e);
}
// Release the filter chain (if any) for this request
if (filterChain != null) {
if (request.isComet()) {
// If this is a Comet request, then the same chain will be used for the
// processing of all subsequent events.
filterChain.reuse();
} else {
filterChain.release();
}
}
// Deallocate the allocated servlet instance
try {
if (servlet != null) {
//servlet释放
wrapper.deallocate(servlet);
}
} catch (Throwable e) {
container.getLogger().error(sm.getString("standardWrapper.deallocateException",
wrapper.getName()), e);
if (throwable == null) {
throwable = e;
exception(request, response, e);
}
}
// If this servlet has been marked permanently unavailable,
// unload it and release this instance
try {
if ((servlet != null) &&
(wrapper.getAvailable() == Long.MAX_VALUE)) {
wrapper.unload();
}
} catch (Throwable e) {
container.getLogger().error(sm.getString("standardWrapper.unloadException",
wrapper.getName()), e);
if (throwable == null) {
throwable = e;
exception(request, response, e);
}
}
long t2=System.currentTimeMillis();
long time=t2-t1;
processingTime += time;
if( time > maxTime) maxTime=time;
if( time < minTime) minTime=time;
}