Difference between WhitespaceTokenizerFactory and

问题:

I am new to Solr. By reading Solr's wiki, I don't understand the differences between WhitespaceTokenizerFactory and StandardTokenizerFactory. What's their real difference?

回答1:

They differ in how they split the analyzed text into tokens.

The StandardTokenizer does this based on the following (taken from lucene javadoc):

• Splits words at punctuation characters, removing punctuation. However, a dot that's not followed by whitespace is considered part of a token.
• Splits words at hyphens, unless there's a number in the token, in which case the whole token is interpreted as a product number and is not split.
• Recognizes email addresses and internet hostnames as one token.

The WhitespaceTokenizer does this based on whitespace characters:

A WhitespaceTokenizer is a tokenizer that divides text at whitespace. Adjacent sequences of non-Whitespace characters form tokens.

You should pick the tokenizer that best fits your application. In any case you have to use the same analyzer/tokenizers for indexing and searching!