标签：tomcat 读书笔记 host engine valve
/**
* Return the Context that would be used to process the specified
* host-relative request URI, if any; otherwise return <code>null</code>.
*
* @param uri Request URI to be mapped
*/
public Context map(String uri);根据url来返回一个Context。 public StandardHost() {
super();
pipeline.setBasic(new StandardHostValve());
}StandardHost并没有invoke方法,它需要调用ContainerBase的invoke方法。 //ContainerBase.java
public void invoke(Request request, Response response)throws IOException, ServletException {
pipeline.invoke(request, response);
}另外StandardHostValve这个基础阀会调用StandardHost的map方法获得一个context容器。 public void invoke(Request request, Response response,
ValveContext valveContext)
throws IOException, ServletException {
....
StandardHost host = (StandardHost) getContainer();
//这里调用的是ContainerBase的map方法 最终会调用StandardHost的map方法(两个map方法没有关系 没有//复写 参数都不一样)
Context context = (Context) host.map(request, true);
....
}在ContainerBase的start中有如下的代码
addDefaultMapper(this.mapperClass);看ConntainerBase
ContainerBase.java
protected void addDefaultMapper(String mapperClass) {
......
// Instantiate and add a default Mapper
Class<?> clazz = Class.forName(mapperClass);
Mapper mapper = (Mapper) clazz.newInstance();
mapper.setProtocol("http");
addMapper(mapper);
......
}StandardHost.java
protected void addDefaultMapper(String mapperClass) {
// 参数默认为 "org.apache.catalina.core.StandardHostMapper";
super.addDefaultMapper(this.mapperClass);
} public Container map(Request request, boolean update) {
...
String uri = ((HttpRequest) request).getDecodedRequestURI();
Context context = host.map(uri);
...
return (context);
}在得到上下对象的时候需要一个往返过程，map 方法介绍两个参数，该方法是在 ContainerBase 中的。然后 ContainerBase 类又在它的子对象中查找合适的映射器并调用它的 map 方法。 public void invoke(Request request, Response response,
ValveContext valveContext)
throws IOException, ServletException {
....
StandardHost host = (StandardHost) getContainer();
//这里调用的是ContainerBase的map方法 最终会调用StandardHost的map方法(两个map方法没有关系 没有//复写 参数都不一样)
Context context = (Context) host.map(request, true);
....
HttpServletRequest hreq = (HttpServletRequest) request.getRequest();
String sessionId = hreq.getRequestedSessionId();
if (sessionId != null) {
Manager manager = context.getManager();
if (manager != null) {
Session session = manager.findSession(sessionId);
if ((session != null) && session.isValid())
session.access(); //修改session的最后访问时间
}
}
context.invoke(request, response); //最后调用context的invoke
}
private void applicationConfig() {
...
synchronized (webDigester) {
try {
URL url =
servletContext.getResource(Constants.ApplicationWebXml);
.....
} public URL getResource(String path)
throws MalformedURLException {
DirContext resources = context.getResources();
if (resources != null) {
String fullPath = context.getName() + path;
// this is the problem. Host must not be null
String hostName = context.getParent().getName();
....
}看到最后一行的getParent大家都明白了吧。 public void invoke(Request request, Response response,
ValveContext valveContext)
throws IOException, ServletException {
..........
// Select the Host to be used for this Request
StandardEngine engine = (StandardEngine) getContainer();
Host host = (Host) engine.map(request, true); //同样调用的是Containerbase的map
//addDefaultMapper 怎么来的就不用说//了吧
if (host == null) {
((HttpServletResponse) response.getResponse()).sendError
(HttpServletResponse.SC_BAD_REQUEST,
sm.getString("standardEngine.noHost",
request.getRequest().getServerName()));
return;
}
// Ask this Host to process this request
host.invoke(request, response);
}How tomcat works 读书笔记十三 Host和Engine
标签：tomcat 读书笔记 host engine valve
原文地址：http://blog.csdn.net/dlf123321/article/details/41543369
