Question

我正在尝试在MongoDb中实现一个自动增量列
我正在关注这篇文章：mongodb_autoincrement_sequence 他说要在服务器上创建一个java脚本函数：

function getNextSequenceValue {some logic reading from a Sequence}

然后在插入文档时调用它：

>db.products.insert({
   "_id":getNextSequenceValue("productid")
   ...

我如何使用java框架（Spring和mongoTemplate）做同样的事情？
我试图将调用添加到document.put（newDocument.id，“getNextSequenceValue ...”
但它会将实际的字符串“getNextSequenceValue ...”保存到数据库中，并且不会生成ID

    DBCollection collection = mongoTemplate.getCollection(DbCollections.employee);
    document.put(newDocument.id,"getNextSequenceValue(" +DbSequences.docSeqId + ")");       
    WriteResult result = collection.save(document);

Answer 1

最终使用this

 // connect to MongoDB server.
Mongo mongo = new Mongo("localhost", 27017);
DB database = mongo.getDB("mydb");
DBCollection collection = database.getCollection("testCollection");

// create a simple db object where counter value is 0
DBObject temp = new BasicDBObject("name", "someName").append("counter", 0);

// insert it into the collection
collection.insert(temp);

// create an increment query
DBObject modifier = new BasicDBObject("counter", 1);
DBObject incQuery = new BasicDBObject("$inc", modifier);

// create a search query    
DBObject searchQuery = new BasicDBObject("name", "someName");

// increment a counter value atomically
WriteResult upRes = collection.update(searchQuery, incQuery);

MongoTemplate - 自动增量

1 个答案: