CAT 源码分析之入口

CAT 应用 首先是一个Web应用，web层主要的提供 后台系统配置 和 用户查询操作。

web应用的入口都是从 web.xml 开始的。

web.xml

web.xml工程目录

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    version="2.5">
    <filter>
        <filter-name>cat-filter</filter-name>
        <filter-class>com.dianping.cat.servlet.CatFilter</filter-class>
    </filter>
    <filter>
        <filter-name>domain-filter</filter-name>
        <filter-class>com.dianping.cat.report.view.DomainFilter</filter-class>
    </filter>
    <servlet>
        <servlet-name>cat-servlet</servlet-name>
        <servlet-class>com.dianping.cat.servlet.CatServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet>
        <servlet-name>mvc-servlet</servlet-name>
        <servlet-class>org.unidal.web.MVC</servlet-class>
        <init-param>
            <param-name>cat-client-xml</param-name>
            <param-value>client.xml</param-value>
        </init-param>
        <init-param>
            <param-name>init-modules</param-name>
            <param-value>false</param-value>
        </init-param>
        <load-on-startup>2</load-on-startup>
    </servlet>
    <filter-mapping>
        <filter-name>cat-filter</filter-name>
        <url-pattern>/r/*</url-pattern>
        <dispatcher>REQUEST</dispatcher>
    </filter-mapping>
    <filter-mapping>
        <filter-name>domain-filter</filter-name>
        <url-pattern>/r/*</url-pattern>
        <dispatcher>REQUEST</dispatcher>
    </filter-mapping>
    <filter-mapping>
        <filter-name>cat-filter</filter-name>
        <url-pattern>/s/*</url-pattern>
        <dispatcher>REQUEST</dispatcher>
    </filter-mapping>
    <filter-mapping>
        <filter-name>cat-filter</filter-name>
        <url-pattern>/jsp/*</url-pattern>
        <dispatcher>FORWARD</dispatcher>
    </filter-mapping>
    <servlet-mapping>
        <servlet-name>mvc-servlet</servlet-name>
        <url-pattern>/r/*</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>mvc-servlet</servlet-name>
        <url-pattern>/s/*</url-pattern>
    </servlet-mapping>
    <jsp-config>
        <taglib>
            <taglib-uri>/WEB-INF/app.tld</taglib-uri>
            <taglib-location>/WEB-INF/app.tld</taglib-location>
        </taglib>
    </jsp-config>
</web-app>

 

• servlet 加载
  • cat-servlet 的 load-on-startup 的 第 1 位启动。
  • mvc-servlet 的 load-on-startup 的 第 2 位启动。
  • mvc-servlet 对应的 url-pattern 值有
    • /s/*
    • /r/*
• filter 过滤器注册
  • domain-filter 是 /r/*
  • cat-filter 配置 url-pattern 有
    • /r/*
    • /s/*
    • /jsp/*