web.xml文件配置详解(页 1) - 电脑综合区 - 我爱电脑技术论坛打造最好的电脑自学交流论坛

不和人说话 发表于 2008-6-13 16:09

web.xml文件配置详解

欢迎页
<welcome-file-list>mu3IEH!b
      <welcome-file>/login.jsp</welcome-file>J-r5X$fQ Z3ptY A8VS*i
</welcome-file-list>
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错误代码
<error-page>
      <error-code>404</error-code>6}!\3B}oS)X]j
      <location>/foundHtml.html</location>/IQD$mG\h)`.R^(Q0x
</error-page>
<error-page>
      <error-code>500</error-code>
      <location>/serverHtml.html</location>
</error-page>5Gy%\SHE` Y!}

异常 Ee_/Ec v"iq
<error-page>       <exception-type>java.lang.NullPointException</exception-type>2u0Lp~%yA${
      <location>/serverHtml.html</location>
</error-page>2R[u5Pb(E0]-BY
mrp1U a4S?'deF

所有session超时
<session-config>
      <session-timeout>1</session-timeout>7BOT#{2p5WSt|
</session-config>fM#i~f$s,~ b_
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获取Servlet初始化参数F)^bq|:sl

ServletConfig对象读取初始化参数E/f.R&bs+@5X
ServletConfig config = getServletConfig();;D;a S0v2au
String aa = config.getInitParameter("a");~9j$b`,~'N)U
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  <servlet>
<servlet-name>te</servlet-name>`.zD cIGNZ
<servlet-class>com.gao.te</servlet-class>H3w a6BA?
<init-param>6Fa:~ow$?:]0D-c{
      <param-name>a</param-name>B4L?8{]+@
      <param-value>11</param-value>
</init-param>
  </servlet>6[(\0V2v)z4dFU$H
  <servlet-mapping>B,_:O~'qzt?c
<servlet-name>te</servlet-name>-|@ P oo{
<url-pattern>/te</url-pattern>%vM`BY2JHdS
  </servlet-mapping>-l y)^.N.o ~+L-k
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获取ServletContext初始化参数(全局,所有servlet都有效)

<context-param>
      <param-name>aa</param-name>,WY2[f5m^
      <param-value>111</param-value>Flx%F.h#Zk
</context-param>*]1r5cTg-S"d
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ServletContext context = this.getServletContext();JldT6Z
context.getInitParameter("aa");Dc{lkf-Y

获取工程别名及主版本号与次版本号
<description> 0JG c%|vc
      My JSP/Servlet Examples.
</description>
<display-name>JSP/Servlet Examples</display-name>'XSN+oa!\ y+u
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out.println("Server: " +  application.getServerInfo() + "<br>");             //取得servlet容器的名字
out.println(application.getMajorVersion() + "." + application.getMinorVersion() + "<br>");//主版本号与次版本号 ,`(mzC?$z
out.println("Servlet Context Name: " + application.getServletContextName());       //<display-name>标签的内容
執行的結果如下：
Server: Apache Tomcat/5.0.182B:R hkc(e{
Servlet API: 2.4
Servlet Context Name: JSP/Servlet Examples ,RTDQ:i'k9N'?0j
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过滤器
<filter> |"k'`J0XaG#\
<filter-name>te</servlet-name>-t k.@-F!sg
<filter-class>com.gao.te</servlet-class>
<init-param>~4\lU8o2Q uov?-Vt
      <param-name>a</param-name>3xf^2fm6S
      <param-value>11</param-value>
</init-param>;r$P8s TFm{N
  </filter>YG'_!Ur"v*d

  <filter-mapping>
<filter-name>te</servlet-name>ii,?"xm~-z!t
<url-pattern>/admin/*</url-pattern>       只有admin文件下才经过过滤器5[3c)aB@9B&[
  </filter-mapping>

這可以在web.xml中加以設定，觸發Filter的方式有FORWARD、 INCLUDE、REQUEST與ERROR，即轉發、包含、請求與錯誤網頁請求時，預設的觸發方式是REQUEST，您可以使用< dispatcher>標籤來加以設定，例如：IJ6F6WgA{1G
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<filter-mapping>
  <filter-name>SomeFilter</filter-name> W j2H7W,}5|`"X2Q
  <url-pattern>/somePage.jsp</url-mapping>
  <dispatcher>REQUEST</dispatcher>
  <dispatcher>INCLUDE</dispatcher> 'WU`9rU+O/B}
</filter-mapping>

服务器启动時載入Servlet，可以在web.xml的<servlet>定義時，加入<load-on- startup>值越低优先级越高$o7gb5MY;@
<servlet>
<servlet-name>Servletname1</servlet-name> &D5C["U*Vi5x
<servlet-class>demo.servlet.SomeServlet1</servlet-class>
<load-on-startup>10</load-on-startup> O5V)j*W3^8pTZI
</servlet>
<servlet>
<servlet-name>Servletname2</servlet-name>
<servlet-class>demo.servlet.SomeServlet2</servlet-class>
<load-on-startup>20</load-on-startup> FOz/_|:H*Y!pX8G&Y
</servlet>

瀏覽器發出請求至Servlet的執行順序是： M0H%j.[ s-?/? vE|
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瀏覽器 -> Web 伺服器 -> Servlet 容器 -> service()J&igM4NW8QO
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如果是HttpServlet則會依請求的方法，在service()之後呼叫對應的doXXX()方法。

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配置监听器 (BPF?aN3J3L*r
<listener>
<listener-class>com.gao.AListener</listener-class>g(\q.LN0X
</listener>

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web.xml文件配置详解