查询Tomcat服务器的默认页面

Question

This is a very basic question that i would like to understand.

I am running Fresh Apache tomcat server on port 8080, and when i type URL http://localhost:8080 , i see that browser sends following request to tomcat.

GET / HTTP/1.1
Host: localhost:8080
Connection: keep-alive
Cache-Control: max-age=0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/35.0.1916.114 Safari/537.36
Accept-Encoding: gzip,deflate,sdch
Accept-Language: en-US,en;q=0.8

I see the below http response with Content-type:text/html

My question:

1) How / parameter of GET request mapped to this above html page as response at tomcat side, when tomcat server received this GET request? Is this something to do with below xml element in tomcat/conf/web.xml? What is the flow on tomcat side after receiving this request?

<!-- The mapping for the default servlet -->
    <servlet-mapping>
        <servlet-name>default</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

Answer 1

Tomcat Architecture

A UML sequence diagram of the Request Process Flow will help you to understand it.

Read more about the following sections directly from official document of Apache Tomcat 7:

• Overview - An overview of the Tomcat server architecture with key terms and concepts.
• Server Startup - A detailed description, with sequence diagrams, of how the Tomcat server starts up.
• Request Process Flow - A detailed description of how Tomcat handles a request.

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It might help you to understand the url-pattern

Servlet Matching Procedure

A request may match more than one servlet-mapping in a given context. The servlet container uses a straightforward matching procedure to determine the best match.

The matching procedure has four simple rules.

• First, the container prefers an exact path match over a wildcard path match.

• Second, the container prefers to match the longest pattern .

• Third, the container prefers path matches over filetype matches.

• Finally, the pattern <url-pattern>/</url-pattern> always matches any request that no other pattern matches.

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Have a look at my post How does a servlets filter identify next destination is another filter or a servlet/jsp? for detailed description to understand it visually.

Answer 2

对。这就是这个web.xml.this是Java Web应用程序中最重要的文件之一.GET的/ paramter由内置的servlet映射。为了更好地理解这一点你需要学习一点JSP / Servlet的事情