Handling Byte-Order-Mark Characters in Groovy

A recent article showed how to process Byte Order Mark (BOM) characters within text files when coding in Java. In particular, often manual removal of those characters might be needed when processing text files. The article showed how to remove the BOM characters when using the InputStream and Reader classes as well as how to do it using NIO functionality. It also showed how the BOMInputStream class in Apache Commons IO could be used. It automatically skips over the BOM characters.

Those examples can be run as is in Groovy (albeit after fixing a bug in the first example) but the (complete!) idiomatic solution in Groovy is:

That’s right, Groovy automatically detects the encoding, and removes BOM characters, when using the getText() method along with others like eachLine, splitEachLine, readLines, withReader, and filterLine. The same functionality can be obtained using the newReader method too on files and URLs.

When needed there are variants that let you specify the encoding should you wish to explicitly declare it. In that case, you’d need to handle the BOM characters manually.

Groovy’s methods like getText call an underlying CharsetToolkit class. You can also use that class directly should you wish to learn more about the encoding of a file.