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  • MongoDB 组合多个条件查询($and、$in、$gte、$lte)

    一,问题描述

    数据格式: id, timeStamp,count

    条件1:查询 某个时间段 内的数据: timeStamp BETWEEN startTime AND endTime。比如 timeStamp BETWEEN 1499875200  AND 1499875600

    条件2:记录 的 id 字段 属于某集合: id IN (1001,1002,1003)

    条件3:记录 的count字段 大于某个阈值,比如: count > 10000

    二,代码实现

    条件1实现如下, $gte (greater equal)表示“大于等于 ”。【$lte(lower equal)】表示“小于等于”

        private DBObject timeCondi(long startTimeStamp, long endTimeStamp){
            DBObject queryCondition = new BasicDBObject("$gte", startTimeStamp).append("$lte", endTimeStamp);
            BasicDBObject query = new BasicDBObject("timeStamp", queryCondition);
            return query;
        }

    条件2的实现如下,使用 $in ArrayList<Integer> 来表示 id IN (1001,1002,1003)

        private DBObject inCondi() {
            List<Integer> idList = new ArrayList<Integer>();
            idList.add(1001);
            idList.add(1002);
            idList.add(1003);
    
            BasicDBObject inQuery = new BasicDBObject();
            inQuery.put("id", new BasicDBObject("$in", idList));
            return inQuery;
        }

    组合条件1 和 条件2 查询:(条件1 AND 条件2).List 将所有 AND 组合的条件add进去,然后使用 $and 组合。

        private DBObject andQuery(long startTimeStamp, long endTimeStamp) {
            DBObject timeCondi = timeCondi(startTimeStamp, endTimeStamp);
            DBObject inCondi = inCondi();
    
            List<DBObject> andCondi = new ArrayList<DBObject>();
            andCondi.add(timeCondi);//组合 条件1
            andCondi.add(inCondi);//组合 条件2
    
            BasicDBObject andQuery = new BasicDBObject();
            andQuery.put("$and", andCondi);
            return andQuery;
        }

    条件3:记录 的count字段 大于某个阈值,比如: count > 10000

        private DBObject countCondi(int size) {
            DBObject queryCondition = new BasicDBObject("$gte", size);
            BasicDBObject query = new BasicDBObject("count", queryCondition);
            return query;
        }

    WINDOWS下安装好MongoDB后,MongoDB采用Clietn--Server 模式。WIN10下启动MongoDB服务端:-dbpath 指定 数据存储目录(可自己指定一个)

    D:Program FilesMongoDBServer3.4in>.mongod.exe -dbpath ..data

    另起一个 Cmd命令行,输入:

    D:Program FilesMongoDBServer3.4in>.mongo.exe

    就可以以Shell方式操作MongoDB了。

    输入 exit 退出

    D:Program FilesMongoDBServer3.4in>netstat -ano | findstr 27017  查看端口是否开启

    另外,推荐一个MongoDB的可视化工具:RoboMongoDB。执行相应的查询语句如下:

    三,新版本MongoDB(3.0版本以上),使用Filters来组合多个条件

    查询 timeStamp 在[startTimeStamp, endTimeStamp) 内的所有document

    1     private static Bson timeBetweenCondition(long startTimeStamp, long endTimeStamp) {
    2         Bson condition = Filters.and(Filters.gte("timeStamp", startTimeStamp), Filters.lt("timeStamp", endTimeStamp));
    3         return condition;
    4     }

    上面的示例,使用Filters的and方法连接了两个条件,其实还可以连接多个条件:比如查询 timeStamp 在[startTimeStamp, endTimeStamp) 区间内,并且 uid 在List<Long>uids 内的document

    1     private static Bson multipleAndCondition(long startTimeStamp, long endTimeStamp, List<Long> uids) {
    2         Bson condition = Filters.and(Filters.gte("timeStamp", startTimeStamp), Filters.lt("timeStamp", endTimeStamp), Filters.in("uid", uids));
    3         return condition;
    4     }

    Filters还组合了 IN 条件:比如,查询 uid 在[123, 456, 789]中,可用如下条件:

    1     private static Bson uidInCondition(List<Long> uids) {
    2         Bson condition = Filters.in("uid", uids);
    3         return condition;
    4     }

     具体更多的条件查询,可查看Filters的源代码。关于Filters的更多的用法可参考:Filters的若干使用示例

    四,MongoDB查询时,过滤某些字段

    使用Document对象来指定需要查询或者排除的字段。0 表示不返回该字段的值,1 表示返回该字段的值。

    1     //0 表示 不返回 该字段, 1 表示 返回该字段
    2     private static Document fetchFields() {
    3         Document fetchFields = new Document();
    4         fetchFields.put("_id", 0);//查询的结果 不返回 _id 字段
    5         fetchFields.put("uid", 1);//返回 uid 字段
    6         fetchFields.put("chat", 1);//返回 chat 字段
    7         return fetchFields;
    8     }

    然后再将 fetchFields 对象传入 project()方法即可,如下:

    collection.find(timeBetweenCondition(startTimeStamp, endTimeStamp)).projection(fetchFields())

    整个完整示例参考:

    import com.mongodb.MongoClient;
    import com.mongodb.client.MongoCollection;
    import com.mongodb.client.MongoCursor;
    import com.mongodb.client.MongoDatabase;
    import com.mongodb.client.model.Filters;
    import org.bson.Document;
    import org.bson.conversions.Bson;
    
    import java.time.LocalDateTime;
    import java.time.ZoneId;
    import java.util.Arrays;
    import java.util.List;
    //import static com.mongodb.client.model.Filters.*;
    
    /**
     * Created by Administrator on 2017/10/20.
     */
    public class MongoUtil {
        private static final String HOST = "localhost";
        private static final int PORT = 27017;
        private static final String DB_NAME = "test";
        private static final MongoClient mongoClient = new MongoClient(HOST, PORT);
        private static MongoDatabase getDataBase() {
            return mongoClient.getDatabase(DB_NAME);
        }
    
        private static MongoCollection<Document> getCollection(String collName) {
            return getDataBase().getCollection(collName);
        }
    
        private static Bson timeBetweenCondition(long startTimeStamp, long endTimeStamp) {
            Bson condition = Filters.and(Filters.gte("timeStamp", startTimeStamp), Filters.lt("timeStamp", endTimeStamp));
            return condition;
        }
    
        private static Bson uidInCondition(List<Long> uids) {
            Bson condition = Filters.in("uid", uids);
            return condition;
        }
    
        private static Bson multipleAndCondition(long startTimeStamp, long endTimeStamp, List<Long> uids) {
            Bson condition = Filters.and(Filters.gte("timeStamp", startTimeStamp), Filters.lt("timeStamp", endTimeStamp), Filters.in("uid", uids));
            return condition;
        }
    
    
        //0 表示 不抽取该字段, 1 表示 抽取该字段
        private static Document fetchFields() {
            Document fetchFields = new Document();
            fetchFields.put("_id", 0);//查询的结果 不返回 _id 字段
            fetchFields.put("uid", 1);//返回 uid 字段
            fetchFields.put("chat", 1);//返回 chat 字段
            return fetchFields;
        }
    
        public static void main(String[] args) {
            MongoCollection collection = getCollection("mycollection_name");
            LocalDateTime today = LocalDateTime.of(2017, 8, 29, 0, 0, 0);
            LocalDateTime tomorrow = today.plusDays(1);
    
            long startTimeStamp = today.atZone(ZoneId.systemDefault()).toEpochSecond();
            long endTimeStamp = tomorrow.atZone(ZoneId.systemDefault()).toEpochSecond();
            Bson andCondition = multipleAndCondition(startTimeStamp, endTimeStamp, Arrays.asList(65496L));
    
    //        Bson andCondition = timeBetweenCondition(startTimeStamp, endTimeStamp);
            Document fetchFields = fetchFields();
            MongoCursor<Document> cursor = collection.find(andCondition).projection(fetchFields).iterator();
    
            long count = collection.count(andCondition);
            System.out.println(count);
            while (cursor.hasNext()) {
                Document document = cursor.next();
                String chat = (String) document.get("chat");
                Long uid = (Long) document.get("uid");
                System.out.println("chat:" + chat + ", uid:" + uid);
            }
        }
    }

    五:参考文献

    https://www.mkyong.com/mongodb/java-mongodb-query-document/

    http://farenda.com/mongodb/mongodb-filtering-sorting-and-projections/

    原文:http://www.cnblogs.com/hapjin/p/7450309.html

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  • 原文地址:https://www.cnblogs.com/hapjin/p/7450309.html
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