如何使用 Java 在 MongoDB 中执行通配符搜索 [英] How to perform wildcard search in MongoDB using Java

问题描述

我刚刚开始使用 MongoDB！正在尝试使用此处支持的各种搜索功能.

I am just getting to use MongoDB! Was trying out with variety of search features supported here.

我可以使用以下选项(不考虑大小写)搜索包含 name=MongoDB 的文档 - goDB、Mongo、go.努力在以下选项中搜索文档 - Mon*DB、*on*DB.也就是说，在同一个搜索文本中有多个通配符.

I could search for a document, say containing name=MongoDB with the following options (irrespective of the case) - goDB, Mongo, go. Working out to search for the document in the following options - Mon*DB, *on*DB. That is, having multiple wild-card in the same search text.

任何指针将不胜感激！

推荐答案

你可以做一个 正则表达式匹配 Mongo 中的字段，以下是您如何执行第一个模式:

You can do a Regular expression match on fields in Mongo, here's how you'd do the first of your patterns:

Pattern p = Pattern.compile("Mon.*DB", CASE_INSENSITIVE);
BasicDBObject query = new BasicDBObject("name", p);

// finds all records with "name" matching /Mon.*DB/i
DBCursor cursor = collection.find(query);

但是要小心，许多正则表达式匹配需要全表扫描.这意味着，如果您针对大型集合运行它们，引擎将不得不遍历所有文档(可能会访问磁盘)并单独检查每个文档是否匹配.这比使用索引的查询慢得多.

Be careful, though, many regular expression matches require a full table scan. This means that if you run them against a large collection, the engine will have to iterate over all the documents (probably hitting disk) and check each individually for a match. This is much slower than queries that use indexes.

唯一会命中索引的正则表达式是区分大小写的前缀匹配.您可以像这样搜索所有Mon*"并使用索引:

The only regular expressions that will hit an index are case sensitive prefix matches. You could search for all "Mon*" like this and use an index:

Pattern p = Pattern.compile("^Mon.*");
BasicDBObject query = new BasicDBObject("name", p);

// finds all records with "name" matching /^Mon.*/
DBCursor cursor = collection.find(query);

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