{"id":2647,"date":"2016-03-19T21:03:32","date_gmt":"2016-03-19T19:03:32","guid":{"rendered":"http:\/\/www.extradrm.com\/?p=2647"},"modified":"2020-10-05T21:09:46","modified_gmt":"2020-10-05T19:09:46","slug":"lucene-vs-solr","status":"publish","type":"post","link":"https:\/\/www.extradrm.com\/?p=2647","title":{"rendered":"Lucene vs SolR … Exact Search Problems"},"content":{"rendered":"

Lucene and Solr are 2 differents Apache projects :<\/em><\/strong><\/p>\n

1) Lucene and Solr are NOT created<\/strong> to work together. Only Solr uses Lucene under the hood. Lucene has no clue about Solr API.<\/p>\n

2) Lucene is a powerful search engine framework that lets us add search capability to our application. It exposes easy-to-use API while hiding all the search-related complex operations. Any application can use this library, not just Solr.<\/p>\n

3) Solr is built around Lucene. It is not just a http-wrapper around Lucene but has been known to add more arsenal to Lucene<\/strong>. Solr is ready-to-use out of box. It is a web application that offers infrastructure related and a lot more features in addition to what Lucene offers.<\/p>\n

4) Lucene doesn’t just create the Index for the consumption by Solr<\/strong>. Lucene handles all the search related operations. Any application can use lucene framework.<\/p>\n

Examples are Solr, Elastic Search, LinkedIn (yes, under the hood), etc..<\/p>\n

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Lucene is a low level Java library<\/strong> (with ports to .NET, etc.) which implements indexing, analyzing, searching, etc.<\/p>\n

Solr is a standalone pre-configured product\/webapp which uses Lucene. If you prefer dealing with HTTP API instead of Java API, Solr is for you. Solr has also got some extra features on top (e.g. grouping).<\/p>\n<\/div>\n

A simple way to conceptualize the relationship between Solr and Lucene is that of a car and its engine. You can’t drive an engine, but you can drive a car. Similarly, Lucene is a programmatic library which you can’t use as-is, whereas Solr is a complete application which you can use out-of-box.<\/p>\n

At the heart of Lucene is an Index<\/tt>. You pump your data into the Index<\/tt>, then do searches on the Index<\/tt> to get results out. Document<\/tt> objects are stored in the Index<\/tt>, and it is your job to “convert” your data into Document<\/tt> objects and store them to the Index<\/tt>.<\/p>\n

Adding a Document\/object to Index<\/h3>\n

Now you need to index your documents or business objects. To index an object, you use the Lucene Document<\/tt> class, to which you add the fields that you want indexed. As we briefly mentioned before, a Lucene Document<\/tt> is basically a container for a set of indexed fields. This is best illustrated by an example:<\/p>\n

Document doc = new Document();\r\ndoc.add(new StringField(\"id\", \"Hotel-1345\", Field.Store.YES));\r\ndoc.add(new TextField(\"description\", \"A beautiful hotel\", Field.Store.YES));<\/pre>\n
In the above example, we add two fields, “id” and “description”, with the respective values “Hotel-1345” and “A beautiful hotel” to the document.<\/p>\n
More precisely, to add a field to a document, you create a new instance of the Field<\/tt> class, which can be either a StringField<\/tt> or a TextField<\/tt> (the difference between the two will be explained shortly). A field object takes the following three parameters:<\/p>\n