Interface/enum listing standard mime-type constants

Diving deep into MIME Type classes

Working with MIME types in Java? There's a class for that! Here are a few that come in handy:

Java Enterprise Edition (JavaEE)

Lucky ones playing with JavaEE have this javax.ws.rs.core.MediaType class. It's bursting with standard MIME types:

import javax.ws.rs.core.MediaType;

String jsonMimeType = MediaType.APPLICATION_JSON; // Now serving: JSON
String xmlMimeType = MediaType.APPLICATION_XML; // Little bit of XML for the road?
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Spring Framework

Spring users will find life easier with org.springframework.http.MediaType - a class chock-full of fanciful features for both standard and exclusive MIME types:

import org.springframework.http.MediaType;

MediaType jsonMediaType = MediaType.APPLICATION_JSON; // Spring into JSON action!
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Google Guava

Google Guava's MediaType class is specially tailored to solve GWT (Issue 823) and it provides nothing but clean, straightforward solutions:

import com.google.common.net.MediaType;

String jsonMimeType = MediaType.JSON_UTF_8.toString(); // More than just a pretty face!
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These classes save your time from reinventing MIME types and help to keep bugs at bay.

Keeping your code clean

Here are some tips to keep your MIME type handling squeaky clean:

Maintain consistency

Stay loyal to standard constants, because typos lurk around corners, waiting to wreak havoc.

Expand wisely

If you need custom MIME types, extend or wrap the existing classes/interfaces. Don't go on a wild goose chase!

Keep it lite

Importing MIME type handling can add overhead. Consider the extra baggage before traveling the code landscape.

When files enter the MIME type arena

Ever dreamt of becoming a MIME type handler while dealing with files? Wake up and smell the code, here are your magic beans:

Detective work on MIME types

Java NIO has a knack for sleuthing the MIME type of a file. Comes in mighty handy when your MIME type is dressed in a cloak:

import java.nio.file.Files;
import java.nio.file.Path;

Path path = ...;
String probedMimeType = Files.probeContentType(path); // Undercover agent NIO!
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Mime types on the Web

In the world of HTTP content negotiation, MIME types are currency. Be a high roller by serving accurate MIME types:

response.setContentType(MimeType.APPLICATION_JSON); // "I'll have what client's having"
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This is synonymous with telling your client, "Here's your data and that's how you untangle it!"