java - MongoDB 3.3.0以上版本中QueryBuilder和BasicDBObjectBuilder的使用

Question

第 1 部分

跟进Querying Mongo Collection using QueryBuilder in Mongo 3.3.0的解决方案，我尝试实现建议的方法来实现collection.find()。但被不同的参数所困扰，已将 BasicDBObjectBuilder 传递给相同的内容，如下 -

BasicDBObjectBuilder queryBuilder = BasicDBObjectBuilder.start();

query.getParams().entrySet().stream().forEach(entry -> queryBuilder.add(entry.getKey(), entry.getValue()));


BasicDBObjectBuilder outputQuery = BasicDBObjectBuilder.start();
outputQuery.add(nameKey, 1);

<小时/>

这不能编译:

FindIterable<TDocType> tDocTypeList = collection.find(queryBuilder.get(), outputQuery.get());

<小时/>

这也不会编译:

FindIterable<TDocType> tDocTypeList = collection.find((Bson)queryBuilder.get(), (Bson)outputQuery.get()); 

<小时/>

这也不会编译:

org.bson.Document queryBuilder = new org.bson.Document();

query.getParams().entrySet().stream().forEach(entry -> queryBuilder.put(entry.getKey(), entry.getValue()));

org.bson.Document outputQuery = new org.bson.Document();
outputQuery.put(nameKey, 1); 

FindIterable<TDocType> tDocTypeList = collection.find(queryBuilder, outputQuery); 

Question - How do I specify a projection for the results required out of find() from collections?

<小时/>

第 2 部分

一方面，我可以简单地替换 mongo 3.0.4 java 驱动程序的代码 -

DBObject dbObject = collection.findOne(new QueryBuilder().put(ids).is(id).get())

到

Bson filter = Filters.eq(ids, id);
TDocType doc = collection.find(filter).first();

现在，如果我们有一个实现，通过迭代构建查询，如示例代码所示 -

for(Map.Entry<String, Object> entry : query.getParams().entrySet()) {
    // this is where its building the query
    if(some condition) {
        queryBuilder.put(entry.getKey()).is(entry.getValue()); 
    }
    if(some other condition) {
        queryBuilder.put(entry.getKey()).in(query.getValues());
    }
}

Question - Is there a way to implement such appending query Filters with current mongo 3.3.0+ as well?

Answer 1

find 方法的第二个参数是结果类型。尝试如下。

FindIterable<TDocType> tDocTypeList = dbCollection.find(filter, TDocType.class);

投影更新

FindIterable<TDocType> tDocTypeList = dbCollection.find(filter, TDocType.class).projection(outputQuery);

附加过滤器的更新

List<Bson> filters = new ArrayList<>();
for (Map.Entry<String, Object> entry : query.getParams().entrySet()) {
        // this is where its building the query
   if (some condition){
       filters.add(Filters.eq(entry.getKey(), entry.getValue()));
   }
   if (some other condition){
       filters.add(Filters.in(entry.getKey(), query.getValues()));
   }
}
FindIterable<TDocType> docType = dbCollection.find(Filters.and(filters));