Why after configure this, request can be redirected to acegi?

<filter>
    <filter-name>Acegi Filter Chain Proxy</filter-name>
    <filter-class>
        org.acegisecurity.util.FilterToBe开发者_高级运维anProxy
    </filter-class>
    <init-param>
        <param-name>targetClass</param-name>
        <param-value>
            org.acegisecurity.util.FilterChainProxy
        </param-value>
    </init-param>
</filter>

<filter-mapping>
    <filter-name>Acegi Filter Chain Proxy</filter-name>
    <url-pattern>/*</url-pattern>
    <dispatcher>FORWARD</dispatcher>
    <dispatcher>REQUEST</dispatcher>
</filter-mapping>

Can someone explain what's these configuration for , or useful references . Thanks in advance !

This is configuring your webapp to use Acegi security filters. Depending on the associated config files, this will give you things like login / authentication via a number of means, a local "user details" service (or integration with LDAP, etc), an authorization model, access control to selected pages, etc.

Acegi is the old name for SpringSecurity. (The name changed with version 2.0, and SS is now at 3.0.x)

Online documentation for Acegi may still be found at http://acegisecurity.org/reference.html.