spring data how query注解查询mongo数据库语法

答：你可以使用@Query注解来编写自定义查询，在该注解中使用MongoDB的查询语法。例如，可以使用以下查询语法来实现模糊查询：

@Query("{'name': {$regex: ?0 }}")

List<Person> findByNameRegex(String regex);

可以在查询方法中使用该注解，通过问号参数的方式传递查询的参数。

相关问题

how to query data using mongo in java

To query data using MongoDB in Java, you can use the following steps:

1. Create a MongoClient instance to connect to the MongoDB server.

MongoClient mongoClient = new MongoClient("localhost", 27017);

2. Get a reference to the database you want to query.

MongoDatabase database = mongoClient.getDatabase("mydb");

3. Get a reference to the collection you want to query.

MongoCollection<Document> collection = database.getCollection("mycollection");

4. Build a query using the QueryBuilder class.

QueryBuilder queryBuilder = QueryBuilder.start("name").is("John");

5. Execute the query on the collection.

FindIterable<Document> result = collection.find(queryBuilder.get());

6. Iterate over the result set to retrieve the data.

for (Document doc : result) {
    System.out.println(doc.toJson());
}

Note: This code requires the MongoDB Java driver to be installed in your project.

how to query mongo data in python

To query MongoDB data in Python, you can use the PyMongo library. Here's an example of querying a MongoDB collection for documents that match a specific criteria:

import pymongo

# connect to the MongoDB server
client = pymongo.MongoClient("<mongodb_uri>")

# select the database and collection
db = client["mydatabase"]
col = db["mycollection"]

# define the query criteria
query = { "name": "John" }

# execute the query and retrieve the matching documents
results = col.find(query)

# iterate over the results and print them
for doc in results:
    print(doc)

In this example, replace `<mongodb_uri>` with the URI of your MongoDB server, `"mydatabase"` with the name of your database, `"mycollection"` with the name of your collection, and `"name": "John"` with the criteria you want to use for the query.