301 Redirects Made Easy In Java

I’ve just released a new version of visural-common – 0.3.2.

This version includes a new Servlet Filter, which makes 301-redirects in Java a breeze.

You’d recall that 301 redirects are useful for SEO (and just general good practice) for when you move content to another place, or to create a “canonical” version of a piece of content. Matt Cutt‘s has done a few posts about 301 vs. 302 redirects and when you should use each, but this post pretty much summarizes the use-case for this filter.

Using the filter is easy, just create a class that extends from PermanentRedirectFilter:

public class MyRedirect extends PermanentRedirectFilter {
    public void configureRoutes() {
        // ... your config goes in here ...
        // e.g.
        fromHost("mydomain.com").to("www.mydomain.com");

        // urls work too
        fromURL("http://www.mydomain.com/index.jsp")
             .to("http://www.mydomain.com/");

        fromURL("http://www.mydomain.com/blog/post.jsp?p=123")
            .to("http://www.mydomain.com/blog/2010/06/how-to-do-301-redirects-in-java");

        // you could also use this to move your domain to another place altogether.
        // The same page url and parameters will be used after the host.
        fromHost("www.myolddomain.com").to("www.other.com");
    }
}

Pretty easy and efficient syntax.

You’ll then want to add this to your web.xml in the usual way for configuring a filter, e.g.:

    <filter>
        <filter-name>MyRedirectFilter</filter-name>
        <filter-class>com.mycom.MyRedirectFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>MyRedirectFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

Done and done – that’s all there is to it.

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