struts2核心工作流程与原理1 - Scripts 学盟

FilterDispatcher进行初始化并启用核心doFilter
其代码如下：
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) req;
HttpServletResponse response = (HttpServletResponse) res;
ServletContext servletContext = filterConfig.getServletContext();
// 在这里处理了HttpServletRequest和HttpServletResponse。
DispatcherUtils du = DispatcherUtils.getInstance();
du.prepare(request, response);//正如这个方法名字一样进行locale、encoding以及特殊request parameters设置
try {
request = du.wrapRequest(request, servletContext);//对request进行包装
} catch (IOException e) {
String message = "Could not wrap servlet request with MultipartRequestWrapper!";
LOG.error(message, e);
throw new ServletException(message, e);
}
ActionMapperIF mapper = ActionMapperFactory.getMapper();//得到action的mapper
ActionMapping mapping = mapper.getMapping(request);// 得到action 的 mapping
if (mapping == null) {
// there is no action in this request, should we look for a static resource?
String resourcePath = RequestUtils.getServletPath(request);
if ("".equals(resourcePath) && null != request.getPathInfo()) {
resourcePath = request.getPathInfo();
}
if ("true".equals(Configuration.get(WebWorkConstants.WEBWORK_SERVE_STATIC_CONTENT))
&& resourcePath.startsWith("/webwork")) {
String name = resourcePath.substring("/webwork".length());
findStaticResource(name, response);
} else {
// this is a normal request, let it pass through
chain.doFilter(request, response);
}
// WW did its job here
return;
}
Object o = null;
try {
//setupContainer(request);
o = beforeActionInvocation(request, servletContext);
//整个框架最最核心的方法，下面分析
du.serviceAction(request, response, servletContext, mapping);
} finally {
afterActionInvocation(request, servletContext, o);
ActionContext.setContext(null);
}
}
du.serviceAction(request, response, servletContext, mapping);
//这个方法询问ActionMapper是否需要调用某个Action来处理这个（request）请求，如果ActionMapper决定需要调用某个Action，FilterDispatcher把请求的处理交给ActionProxy
public void serviceAction(HttpServletRequest request, HttpServletResponse response, String namespace, String actionName, Map requestMap, Map parameterMap, Map sessionMap, Map applicationMap) {
HashMap extraContext = createContextMap(requestMap, parameterMap, sessionMap, applicationMap, request, response, getServletConfig()); //实例化Map请求，询问ActionMapper是否需要调用某个Action来处理这个（request）请求
extraContext.put(SERVLET_DISPATCHER, this);
OgnlValueStack stack = (OgnlValueStack) request.getAttribute(ServletActionContext.WEBWORK_VALUESTACK_KEY);
if (stack != null) {
extraContext.put(ActionContext.VALUE_STACK,new OgnlValueStack(stack));
}
try {
ActionProxy proxy = ActionProxyFactory.getFactory().createActionProxy(namespace, actionName, extraContext);
//这里actionName是通过两道getActionName解析出来的, FilterDispatcher把请求的处理交给ActionProxy，下面是ServletDispatcher的 TODO:
request.setAttribute(ServletActionContext.WEBWORK_VALUESTACK_KEY, proxy.getInvocation().getStack());
proxy.execute();
//通过代理模式执行ActionProxy
if (stack != null){
request.setAttribute(ServletActionContext.WEBWORK_VALUESTACK_KEY,stack);
}
} catch (ConfigurationException e) {
log.error("Could not find action", e);
sendError(request, response, HttpServletResponse.SC_NOT_FOUND, e);
} catch (Exception e) {
log.error("Could not execute action", e);
sendError(request, response, HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e);
}
}

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