Servlet filter example concept for use filter for do something before

Servlet filter example concept for use filter for do something before
Before main logic if  you need to do some thing like .. encode, check authorize
you can use Servlet filter to help you

Step 1 : Create servlet class  implements Filter  interface
Step 2 : Implements method  doFilter(ServletRequest req, ServletResponse res,FilterChain chain)

You can use request and response to chain filter and do something you want.

Step 3 : add config in web.xml like this
<filter>
    <filter-name>myFilter</filter-name>
    <filter-class>
        mypaclate.MyFilter
    </filter-class>
    <init-param>
        <param-name>test-filter</param-name>
        <param-value>This Call Filter</param-value>
    </init-param>
</filter>
<filter-mapping>
    <filter-name>MyFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>