Java Mongodb regex query

Question

I have to run this query in Java

 db.Users.find({"name": /^ind/i})

My Java code is

Document findQuery = new Document();
findQuery.append("name", Pattern.compile("/^"+name+"/i"));
FindIterable<Document> iterable = db.getCollection("Users").find(findQuery);

It is not returning any data, I think the above java code is converting

> /^ind/i into "/^ind/i"

Thanks in advance.

Edit:

Based on stribizhev suggestion updated the query and its worked

db.Users.find({"name": {"$regex": /^ind/, "$options": "i"}})

Java code

Document regQuery = new Document();
regQuery.append("$regex", "^(?)" + Pattern.quote(name));
regQuery.append("$options", "i");

Document findQuery = new Document();
findQuery.append("name", regQuery);
FindIterable<Document> iterable = db.getCollection("Users").find(findQuery);

In Java, do not use regex delimiters. Try "^(?i)"+Pattern.quote(name) instead of "/^"+name+"/i". — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Sep 22, 2015 at 10:19
Thanks, it worked so basically "^(?)"+Pattern.quote("ind") converted value to ^(?)\Qind\E — Indrajeet
– Indrajeet, Commented Sep 22, 2015 at 10:31
Please specify which import you use. import java.util.regex.Pattern; — Marco Fantasia
– Marco Fantasia, Commented Sep 26, 2017 at 6:56
Something similar worked for me - findQuery.append("name", new BsonRegularExpression(regexLiteral)); — TimeTraveler
– TimeTraveler, Commented Jan 6, 2021 at 6:55

Wiktor Stribiżew · Accepted Answer · 2015-09-22 10:33:48Z

9

You cannot use regex delimiters in Java Pattern.compile, as there are other means in Java (e.g. flags) to do the same.

To enforce case-insensitive search, use inline modifier (?i). So, use "^(?i)"+Pattern.quote(name) instead of "/^"+name+"/i".

Pattern.quote just escapes all regex metacharacters so that they were treated as literals (same as \Q...\E).

answered Sep 22, 2015 at 10:33

Wiktor Stribiżew

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2 Comments

Indrajeet Over a year ago

Yes, exactly so I updated the mongo query as well to use this db.Users.find({"name": {"$regex": /^ind/, "$options": "i"}}) Java code is Document regQuery = new Document(); regQuery.append("$regex", "^(?)" + Pattern.quote(name)); regQuery.append("$options", "i");

Wiktor Stribiżew Over a year ago

You may add this code you end up with to the question, at the end.

pulu · Accepted Answer · 2016-10-06 13:03:17Z

8

I guess there is a more elegant way to do that in Java, by using the provided Filters in the MongoDB Java Driver (version 3 and above):

Document query = new Document("equipment","gloves");

//whatever pattern you need. But you do not need the "/" delimiters
String pattern = ".*" + query.getString("equipment") + ".*";

//find(regex("field name", "pattern", "options"));
collection.find(regex("equipment", pattern, "i"));

answered Oct 6, 2016 at 13:03

pulu

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Comments

hestellezg · Accepted Answer · 2022-04-19 14:22:25Z

8

You could use Pattern -and Filters-

Pattern regex = Pattern.compile("ind", Pattern.CASE_INSENSITIVE);
Bson filter = Filters.eq("name", regex);

The object Pattern has some other flags, as you can see here

edited Apr 19, 2022 at 14:22

answered Jun 23, 2017 at 21:30

hestellezg

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Comments

Mihael · Accepted Answer · 2018-08-14 14:04:21Z

3

Most of the answers here are not working for me (maybe not up-to-date MongoDB Java driver). Here is what worked for me:

Document regexQuery = new Document();
regexQuery.append("$regex", ".*" + Pattern.quote(searchTerm) + ".*");
BasicDBObject criteria = new BasicDBObject("name", regexQuery);
DBCursor cursor = collection.find(criteria);

answered Aug 14, 2018 at 14:04

Mihael

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