Question

我使用java async driver for mongoDb而不是默认驱动程序

我有一个带有'collect'集合的db'test'，每个文档都在下面给出的表格中，其中time是10位unix时间戳

{ "_id", "userId", "programId", "time" }

我想写一个等同于下面给出的sql查询的查询，其中input1是unix时间戳格式的当前时间，input2是userId作为输入

SELECT * 
FROM collect 
WHERE time >= input1 AND userId = input2 
ORDER BY time DESC 
LIMIT 30

我做了类似的事

collection = db.getCollection("ProgramBookings"); Long Datetimesatmp =
new Date().getTime() / 1000;

Aggregate.Builder builder = new Aggregate.Builder();

builder = (builder.match(where("time").
          greaterThan(Datetimesatmp.toString()).and("userId")     .equals(userId.toString())).sort(desc("time"))).limit(30);

Aggregate d1 = builder.build();

这里我的意思是只检索符合条件的列表'时间'。但我被困在这里谷歌搜索后找不到很多有用的链接。我提到this link来执行上面给出的代码。有没有一种简单的方法可以做到这一点。

编辑：我想将值添加到List of ProgramTime对象，就像

public class ProgramTime {

    private Integer userId;     
      private Integer programId;    
      private Long time; 
}

Answer 1

我不认为聚合框架是正确的选择。我会直接'找'。有一个Find类和嵌套Find.Builder类用于构造更复杂的查询。

import static com.allanbank.mongodb.builder.QueryBuilder.where;

import com.allanbank.mongodb.MongoClient;
import com.allanbank.mongodb.MongoCollection;
import com.allanbank.mongodb.MongoFactory;
import com.allanbank.mongodb.MongoIterator;
import com.allanbank.mongodb.bson.Document;
import com.allanbank.mongodb.builder.Find;
import com.allanbank.mongodb.builder.Sort;

public class StackOverFlow {
    // SELECT * FROM collect
    // WHERE time >= input1 AND userId = input2
    // ORDER BY time DESC
    // LIMIT 30
    public static void query(long input1, String input2) {
        MongoClient client = MongoFactory
                .createClient("mongodb://localhost:27017/");

        // SELECT * FROM collect -- Kinda...
        MongoCollection collection = client.getDatabase("test").getCollection(
                "collect");

        Find.Builder builder = Find.builder();
        // WHERE time >= input1 AND userId = input2
        builder.query(where("time").greaterThan(input1).and("userId")
                .equals(input2));
        // ORDER BY time DESC
        builder.sort(Sort.desc("time"));
        // LIMIT 30
        builder.limit(30);

        try (MongoIterator<Document> iter = collection.find(builder)) {
            for (Document doc : iter) {
                System.out.println(doc);
            }
        }
    }
}

MongoDb java异步驱动程序：从集合中排序和限制值的正确查询是什么

1 个答案: