아파치 톰캣 서블릿/JSP 컨테이너

아파치 톰캣 7

Version 7.0.28-dev, Oct 2 2013
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아파치 톰캣 개발

디폴트 서블릿 레퍼런스

Table of Contents
What is the DefaultServlet
디폴트 서블릿은 정적 자원들과 디렉토리 목록(디렉토리 목록이 지원된다면)을 지원하는 서블릿이다. The default servlet is the servlet which serves static resources as well as serves the directory listings (if directory listings are enabled).
Where is it declared?
$CATALINA_BASE/conf/web.xml에 아래와 같이 전역적으로 선언되어 있다. By default here is it's declaration:
    <servlet>
        <servlet-name>default</servlet-name>
        <servlet-class>
          org.apache.catalina.servlets.DefaultServlet
        </servlet-class>
        <init-param>
            <param-name>debug</param-name>
            <param-value>0</param-value>
        </init-param>
        <init-param>
            <param-name>listings</param-name>
            <param-value>false</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

...

    <servlet-mapping>
        <servlet-name>default</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

따라서, 디폴트 서블릿은 webapp의 시작시에 로드되고 디렉토리 목록은 접근할 수 없으며 디버깅 기능은 작동하지 않는 상태다. So by default, the default servlet is loaded at webapp startup and directory listings are disabled and debugging is turned off.
What can I change?
디폴트 서블릿은 아래와 같은 초기화 인자를 허용한다. The DefaultServlet allows the following initParamters:
debug 디버깅 레벨. 톰캣 개발자가 아니라면 그다지 쓸모있진 않다. 이 글을 쓰는 시점에 유용한 값은 0,1,11,1000 가 있다.[0] Debugging level. It is not very useful unless you are a tomcat developer. As of this writing, useful values are 0, 1, 11, 1000. [0]
listings welcome 파일이 없으면, 디렉토리 목록이 보여지는가? If no welcome file is present, can a directory listing be shown? 설정값은 truefalse가 된다. [false] value may be true or false [false]
Welcome 파일들은 서블릿 API의 일부이다. Welcome files are part of the servlet api.
경고: 많은 엔트리를 포함하는 디렉토리 목록은 부하를 유발한다. 큰 디렉토리 목록에 대한 여러번의 요청이 서버의 자원을 눈에 띌 정도로 소모하게 된다. WARNING: Listings of directories containing many entries are expensive. Multiple requests for large directory listings can consume significant proportions of server resources.
readmeFile 디렉토리 목록이 나타난다면, readme 파일또한 목록과 함께 보여진다. 이 파일은 그대로 삽입되므로 HTML 을 포함할 수도 있다. If a directory listing is presented, a readme file may also be presented with the listing. This file is inserted as is so it may contain HTML.
globalXsltFile 디렉토리 목록을 수정하고 싶다면, XSL 변환을 사용하라. 이 값은 모든 디렉토리 목록에 사용되는 파일의 절대 경로 이름이다. 이는 컨텍스트 혹은 디렉토리당 override 될 수 있다. 아래의 contextXsltFilelocalXsltFile 를 살펴보자. xml 형식이 자세히 나와 있다. If you wish to customize your directory listing, you can use an XSL transformation. This value is an absolute file name which be used for all directory listings. This can be overridden per context and/or per directory. See contextXsltFile and localXsltFile below. The format of the xml is shown below.
contextXsltFile You may also customize your directory listing by context by configuring contextXsltFile. This should be a context relative path (e.g.: /path/to/context.xslt). This overrides globalXsltFile. If this value is present but a file does not exist, then globalXsltFile will be used. If globalXsltFile does not exist, then the default directory listing will be shown.
localXsltFile You may also customize your directory listing by directory by configuring localXsltFile. This should be a relative file name in the directory where the listing will take place. This overrides globalXsltFile and contextXsltFile. If this value is present but a file does not exist, then contextXsltFile will be used. If contextXsltFile does not exist, then globalXsltFile will be used. If globalXsltFile does not exist, then the default directory listing will be shown.
input Input buffer size (in bytes) when reading resources to be served. [2048]
output Output buffer size (in bytes) when writing resources to be served. [2048]
readonly Is this context "read only", so HTTP commands like PUT and DELETE are rejected? [true]
fileEncoding File encoding to be used when reading static resources. [platform default]
sendfileSize If the connector used supports sendfile, this represents the minimal file size in KB for which sendfile will be used. Use a negative value to always disable sendfile. [48]
useAcceptRanges If true, the Accept-Ranges header will be set when appropriate for the response. [true]
How do I customize directory listings?

You can override DefaultServlet with you own implementation and use that in your web.xml declaration. If you can understand what was just said, we will assume you can read the code to DefaultServlet servlet and make the appropriate adjustments. (If not, then that method isn't for you)

You can use either localXsltFile or globalXsltFile and DefaultServlet will create an xml document and run it through an xsl transformation based on the values provided in localXsltFile and globalXsltFile. localXsltFile is first checked, followed by globalXsltFile, then default behaviors takes place.

Format:

    <listing>
     <entries>
      <entry type='file|dir' urlPath='aPath' size='###' date='gmt date'>
        fileName1
      </entry>
      <entry type='file|dir' urlPath='aPath' size='###' date='gmt date'>
        fileName2
      </entry>
      ...
     </entries>
     <readme></readme>
    </listing>
  • size will be missing if type='dir'
  • Readme is a CDATA entry

The following is a sample xsl file which mimics the default tomcat behavior:
<?xml version="1.0"?>

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  version="1.0">

  <xsl:output method="xhtml" encoding="iso-8859-1" indent="no"/>

  <xsl:template match="listing">
   <html>
    <head>
      <title>
        Sample Directory Listing For
        <xsl:value-of select="@directory"/>
      </title>
      <style>
        h1{color : white;background-color : #0086b2;}
        h3{color : white;background-color : #0086b2;}
        body{font-family : sans-serif,Arial,Tahoma;
             color : black;background-color : white;}
        b{color : white;background-color : #0086b2;}
        a{color : black;} HR{color : #0086b2;}
      </style>
    </head>
    <body>
      <h1>Sample Directory Listing For
            <xsl:value-of select="@directory"/>
      </h1>
      <hr size="1" />
      <table cellspacing="0"
                  width="100%"
            cellpadding="5"
                  align="center">
        <tr>
          <th align="left">Filename</th>
          <th align="center">Size</th>
          <th align="right">Last Modified</th>
        </tr>
        <xsl:apply-templates select="entries"/>
        </table>
      <xsl:apply-templates select="readme"/>
      <hr size="1" />
      <h3>Apache Tomcat/7.0</h3>
    </body>
   </html>
  </xsl:template>


  <xsl:template match="entries">
    <xsl:apply-templates select="entry"/>
  </xsl:template>

  <xsl:template match="readme">
    <hr size="1" />
    <pre><xsl:apply-templates/></pre>
  </xsl:template>

  <xsl:template match="entry">
    <tr>
      <td align="left">
        <xsl:variable name="urlPath" select="@urlPath"/>
        <a href="{$urlPath}">
          <tt><xsl:apply-templates/></tt>
        </a>
      </td>
      <td align="right">
        <tt><xsl:value-of select="@size"/></tt>
      </td>
      <td align="right">
        <tt><xsl:value-of select="@date"/></tt>
      </td>
    </tr>
  </xsl:template>

</xsl:stylesheet>
How do I secure directory listings?
Use web.xml in each individual webapp. See the security section of the Servlet specification.

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