Servlet 容器对URI的处理

问题
请求到达server以后，server是怎样处理URI请求资源路径的，在与web.xml文件里的映射进行比对时的原则是什么。

方案
针对精确匹配、通配符匹配、后缀匹配三种模式改动web.xml文件里的配置，查看不同比对原则的訪问结果

步骤
step1：新建URIServlet.java 文件
代码例如以下：

package web;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class URIServlet extends HttpServlet{
    protected void service(HttpServletRequest request,
            HttpServletResponse response)
            throws ServletException,IOException{
        System.out.println("这里是URIServlet的service()方法");
    }
}

step2：改动web.xml文件
例如以下：

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" 
    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_3_0.xsd">
  <display-name></display-name> 
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  <servlet>
    <servlet-name>uri1</servlet-name>
    <servlet-class>web.URIServlet</servlet-class>
  </servlet>
  <!-- URI匹配,每次仅仅能开放一个servlet-mapping -->
  <!-- 
  <servlet-mapping>
    <servlet-name>uri1</servlet-name>
    <url-pattern>/abc/abc.html</url-pattern>
  </servlet-mapping>
  -->
  <servlet-mapping>
    <servlet-name>uri1</servlet-name>
    <url-pattern>/abc/*</url-pattern>
  </servlet-mapping>
  <!-- 
  <servlet-mapping>
    <servlet-name>uri1</servlet-name>
    <url-pattern>*.do</url-pattern>
  </servlet-mapping>
   -->
</web-app>

step3：新建uri.html文件、測试
例如以下：

<!DOCTYPE html>
<html>
  <head>
    <title>uri.html</title>

    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="this is my page">
    <meta http-equiv="content-type" content="text/html; charset=UTF-8">

    <!--<link rel="stylesheet" type="text/css" href="./styles.css">-->

  </head>

  <body style="font-size:24">
    <h3>请求资源路径的 处理</h3>
    <ul>
      <li style="margin:40px">精确匹配
        <ul>
            <li>url-pattern:/abc/abc.html
            <li><a href="abc.html">abc.html</a>
            <li><a href="abc/abc.html">abc/abc.html</a>
        </ul>
        <li style="margin:40px">通配符匹配
        <ul>
            <li>url-pattern:/abc/*
            <li><a href="abc.html">abc.html</a>
            <li><a href="abc/abc.html">abc/abc.html</a>
        </ul>
        <li style="margin:40px">精确匹配   //注意li/ul的使用，效果例如以下图
        <ul>   
            <li>url-pattern:*.do
            <li><a href="abc.do">abc.do</a>
            <li><a href="abc/abc.do">abc/abc.do</a>
        </ul>
    </ul>
  </body>
</html>

==============================
測试界面例如以下所看到的：

測试成功时：在Console会输出：
这里是URIServlet的service()方法
（出如今Server startup in 36041 ms的以下）

刚開始測试时，出现一个错误：

严重: ContainerBase.addChild: start: 
org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/URIServletTest]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:649)
    at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1247)
    at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1898)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.IllegalArgumentException: Servlet mapping specifies an unknown servlet name uril

原因：web.xml文件里同一时候包括了多个
解决方法：每次仅仅开启一个,不用的凝视掉