Jetty的DispatcherType(和其他1000个未记录的东西)

Question

有人可以告诉我,DispatcherType正在做什么？

似乎是一个重要的配置.

通过指向诸如ServletContextHandler#addFilter之类的东西,类的使用也没有帮助我,这是用明智的词语"记录"的:convenience method to add a filter.

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一般来说,任何机会都可以"理解" 未记录的 Jetty API而无需代码示例 - 搜索 - 乐趣或尝试 - 失败和奇迹？

Answer 1

这也是web.xml中的一个设置; 并且可能已经存在了相当长的一段时间.

http://download.oracle.com/docs/cd/B32110_01/web.1013/b28959/filters.htm#BCFIEDGB

配置转发或包含目标的过滤器

本节提供了一些示例配置,以使过滤器作用于前进或包含目标.我们从过滤器声明开始,然后是备用过滤器映射配置:

<filter>
    <filter-name>myfilter</filter-name>
    <filter-class>mypackage.MyFilter</filter-class>
</filter>

要执行MyFilter以过滤名为includedservlet的包含目标,请执行以下操作:

<filter-mapping>
   <filter-name>myfilter</filter-name>
   <servlet-name>includedservlet</servlet-name>
   <dispatcher>INCLUDE</dispatcher>
</filter-mapping>

请注意,include()调用可以来自应用程序中的任何servlet(或其他资源).另请注意,除非您有另一个值为REQUEST的元素,否则MyFilter不会执行includedservlet的直接请求.

要执行MyFilter以过滤通过URL模式"/ mypath /"直接请求的任何servlet,或执行它以过滤通过以"/ mypath /"开头的URL模式调用的任何前向目标:

<filter-mapping>
   <filter-name>myfilter</filter-name>
   <url-pattern>/mypath/*</url-pattern>
   <dispatcher>FORWARD</dispatcher>
   <dispatcher>REQUEST</dispatcher>
</filter-mapping>

~~~~~~~~~~~~~~~~~~~~~~

此外,默认为Request; 阅读下面的applyTo(...)方法:

http://grepcode.com/file/repo1.maven.org/maven2/org.eclipse.jetty/jetty-servlet/8.0.0.M0/org/eclipse/jetty/servlet/FilterMapping.java#FilterMapping.0_dispatches

Answer 2

添加到Asad的答案,调度程序不是特定于Jetty的,它是2.2版之前的servlet规范的一部分.以下是来自web-app_2_5.xsd的调度程序值的官方说明:

<xsd:complexType name="dispatcherType">
    <xsd:annotation>
        <xsd:documentation>

The dispatcher has four legal values: FORWARD, REQUEST, INCLUDE,
and ERROR. A value of FORWARD means the Filter will be applied
under RequestDispatcher.forward() calls.  A value of REQUEST
means the Filter will be applied under ordinary client calls to
the path or servlet. A value of INCLUDE means the Filter will be
applied under RequestDispatcher.include() calls.  A value of
ERROR means the Filter will be applied under the error page
mechanism.  The absence of any dispatcher elements in a
filter-mapping indicates a default of applying filters only under
ordinary client calls to the path or servlet.

        </xsd:documentation>
    </xsd:annotation>

    <xsd:simpleContent>
        <xsd:restriction base="javaee:string">
            <xsd:enumeration value="FORWARD"/>
            <xsd:enumeration value="INCLUDE"/>
            <xsd:enumeration value="REQUEST"/>
            <xsd:enumeration value="ERROR"/>
        </xsd:restriction>
    </xsd:simpleContent>
</xsd:complexType>