mongodb objetcid_mongoDB Java SDK CRUD操作例子

以下使用MongoDB Java SDK进行CRUD操作的示例：

1. 连接到MongoDB数据库

MongoClient mongoClient = new MongoClient("localhost", 27017);
MongoDatabase database = mongoClient.getDatabase("mydb");

2. 插入数据

MongoCollection<Document> collection = database.getCollection("mycollection");
Document document = new Document("name", "John Doe")
        .append("age", 30)
        .append("email", "johndoe@example.com");
collection.insertOne(document);

3. 查询数据

MongoCollection<Document> collection = database.getCollection("mycollection");
Document query = new Document("name", "John Doe");
FindIterable<Document> results = collection.find(query);
for (Document result : results) {
    System.out.println(result.toJson());
}

4. 更新数据

MongoCollection<Document> collection = database.getCollection("mycollection");
Document query = new Document("name", "John Doe");
Document update = new Document("$set", new Document("age", 35));
collection.updateOne(query, update);

5. 删除数据

MongoCollection<Document> collection = database.getCollection("mycollection");
Document query = new Document("name", "John Doe");
collection.deleteOne(query);

注意：以上代码只是示例，实际使用时需要根据具体情况进行修改。