Spring - source code analysis - DispatcherServlet (... to be continued)

1, ContextLoaderListener listener

public class ContextLoaderListener extends ContextLoader implements ServletContextListener{
    public ContextLoaderListener() {
    }

    public ContextLoaderListener(WebApplicationContext context) {
        super(context);
    }

    //初始化容器
    public void contextInitialized(ServletContextEvent event) {
        this.initWebApplicationContext(event.getServletContext());
    }

    public void contextDestroyed(ServletContextEvent event) {
        this.closeWebApplicationContext(event.getServletContext());
        ContextCleanupListener.cleanupAttributes(event.getServletContext());
    }
}

1. Create a container object

this.context = this.createWebApplicationContext(servletContext);

//查找需要使用的容器类，默认从 contextClass 属性获取，没有该属性，从 ContextLoader.properties 文件中进行读取，采用的是 XmlWebApplicationContext 容器
Class<?> contextClass = this.determineContextClass(sc);
return (ConfigurableWebApplicationContext)BeanUtils.instantiateClass(contextClass);

2, refresh container

this.configureAndRefreshWebApplicationContext(cwac, servletContext);

//1.将 ServletContext 放到容器中
wac.setServletContext(sc);
//2.读取 contextConfigLocation 配置文件路径
configLocationParam = sc.getInitParameter("contextConfigLocation");
//3.刷新容器
wac.refresh();

3, to set the properties ServletContext

//属性名称为 WebApplicationContext.class.getName() + ".ROOT";
servletContext.setAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE, this.context);

2, DispatcherServlet components

1, the assembly is ultimately a Servlet, it will execute the init method and perform multiple service when business calls, the init in HttpServletBean

public final void init() throws ServletException {
    //...省略
    initServletBean();
}

2, initServletBean, implemented in FrameworkServlet

protected final void initServletBean() throws ServletException {
    this.webApplicationContext = initWebApplicationContext();
    //空实现
    initFrameworkServlet();
}

//init实现
WebApplicationContext rootContext =
				WebApplicationContextUtils.getWebApplicationContext(getServletContext());
WebApplicationContext wac = null;
//1.使用的是 XmlWebApplicationContext 容器
wac = createWebApplicationContext(rootContext);
//2.该方法在 DispatcherServlet 中重写，用来初始化 Dispatcher 的相关组件
onRefresh()

3, initialization component. . . To be continued