Servlet-web.xml 常见配置

路径映射

指定一个映射路径

<servlet-mapping>
    <servlet-name>Hello</servlet-name>
    <url-pattern>/hello</url-pattern>
</servlet-mapping>

指定多个映射路径

<servlet-mapping>
    <servlet-name>Hello</servlet-name>
    <url-pattern>/hello</url-pattern>
</servlet-mapping>
<servlet-mapping>
    <servlet-name>Hello</servlet-name>
    <url-pattern>/hello2</url-pattern>
</servlet-mapping>
...

指定通用映射路径

<servlet-mapping>
    <servlet-name>Hello</servlet-name>
    <url-pattern>/hello/*</url-pattern>
</servlet-mapping>

默认请求路径

<servlet-mapping>
    <servlet-name>Hello</servlet-name>
    <url-pattern>/*</url-pattern>
</servlet-mapping>

指定一些后缀或者前缀

<!-- xxx.do -->
<servlet-mapping>
    <servlet-name>Hello</servlet-name>
    <url-pattern>*.do</url-pattern>
</servlet-mapping>

优先级问题

指定了固有的映射路径优先级最高，如果找不到就会走默认的处理请求；

<servlet-mapping>
    <servlet-name>error</servlet-name>
    <url-pattern>/hello</url-pattern>
</servlet-mapping>
<!-- 404 -->
<servlet-mapping>
    <servlet-name>error</servlet-name>
    <url-pattern>/*</url-pattern>
</servlet-mapping>

过滤器配置

<filter>
    <filter-name>CharacterEncodingFilter</filter-name>
    <filter-class>com.demo.filter.CharacterEncodingFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>CharacterEncodingFilter</filter-name>
    <url-pattern>/*</url-pattern> <!--所有请求过滤-->
</filter-mapping>

监听器配置

<listener>
    <listener-class>com.demo.listener.CountOnlineListener</listener-class>
</listener>

session配置

<session-config>
    <!--15分钟后自动失效-->
    <session-timeout>15</session-timeout>
</session-config>

初始化参数

<context-param>
    <param-name>encoding</param-name>
    <param-value>utf-8</param-value>
</context-param>

欢迎页

<welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
</welcome-file-list>