MongoDB模糊查询java实现样例

矫情吗；* 2022-06-05 07:28 386阅读 0赞

在我的mongoDB中北京共有16个区县  
  
![这里写图片描述][SouthEast]  
  
  
其中只有密云和延庆是县，其他的为区，现在要将这两个例外查出来

直接用mongoDB shell命令是这样查询的：

db.country.find({ 'name':{ $regex:/县/},'sheng':'11','level':3})

java实现如下：

package com.adtec.mongodb;
    
    import java.util.Iterator;
    import java.util.regex.Pattern;
    
    import com.mongodb.BasicDBObject;
    import com.mongodb.DB;
    import com.mongodb.DBCollection;
    import com.mongodb.DBCursor;
    import com.mongodb.DBObject;
    import com.mongodb.MongoClient;
    
    /** * * @author 浪丶荡 * <br> * 模糊查询实例 * */
    public class BlurQuery { 
        private String host = "192.168.71.193";
    
        private int port = 27017;
    
        public static void main(String[] args) {
            BlurQuery blurQuery = new BlurQuery();
            //数据库test
            String dbname = "test";
            DB db = blurQuery.getDB(dbname);
            //集合country
            String collectionName = "country";
            //获取结果集
            DBCursor cur = blurQuery.query(db, collectionName);
            //show一下结果
            blurQuery.printDBCursor(cur);
    
    
        }
    
        /** * * @param dbname * @return 获取一个与指定数据库相关联的DB对象 */
        public DB getDB(String dbname) {
    
            @SuppressWarnings("resource")
            MongoClient mongoClient = new MongoClient(host, port);
            @SuppressWarnings("deprecation")
            DB db = mongoClient.getDB(dbname);
            return db;
        }
    
        /** * * @param db * @param name * @return DBCursor * 查询北京市县级单位带"县"字的城市<br> * mongodb vue 是db.country.find({'name':{$regex:/县/},'sheng':'11','level':3}) */
        public DBCursor query(DB db, String collectionName) {
            DBCollection dbColl = db.getCollection(collectionName);
    
            // 模糊匹配正则规则（只要名字里带县字）
            Pattern pattern = Pattern.compile("^.*县.*$", Pattern.CASE_INSENSITIVE);
            BasicDBObject query = new BasicDBObject();
            //加入查询条件
            query.put("name", pattern);
            query.put("sheng", "11");
            query.put("level", 3);
            //按名次升序排序
            BasicDBObject sort = new BasicDBObject();
            // 1,表示正序； －1,表示倒序
            sort.put("name", 1);
            DBCursor cur = dbColl.find(query).sort(sort);
            return cur;
        }
    
        /** * 遍历结果集 * @param cur */
        private void printDBCursor(DBCursor cur) {
            Iterator<DBObject> iterator = cur.iterator();
            while (iterator.hasNext()) {
                System.out.println(iterator.next());
            }
        }
    }

结果：

十一月 21, 2017 3:12:16 下午 com.mongodb.diagnostics.logging.JULLogger log
    信息: Cluster created with settings {hosts=[192.168.71.193:27017], mode=SINGLE, requiredClusterType=UNKNOWN, serverSelectionTimeout='30000 ms', maxWaitQueueSize=500}
    十一月 21, 2017 3:12:16 下午 com.mongodb.diagnostics.logging.JULLogger log
    信息: No server chosen by ReadPreferenceServerSelector{readPreference=primary} from cluster description ClusterDescription{type=UNKNOWN, connectionMode=SINGLE, serverDescriptions=[ServerDescription{address=192.168.71.193:27017, type=UNKNOWN, state=CONNECTING}]}. Waiting for 30000 ms before timing out
    十一月 21, 2017 3:12:16 下午 com.mongodb.diagnostics.logging.JULLogger log
    信息: Opened connection [connectionId{localValue:1, serverValue:14}] to 192.168.71.193:27017
    十一月 21, 2017 3:12:16 下午 com.mongodb.diagnostics.logging.JULLogger log
    信息: Monitor thread successfully connected to server with description ServerDescription{address=192.168.71.193:27017, type=STANDALONE, state=CONNECTED, ok=true, version=ServerVersion{versionList=[3, 4, 5]}, minWireVersion=0, maxWireVersion=5, maxDocumentSize=16777216, roundTripTimeNanos=1732855}
    十一月 21, 2017 3:12:16 下午 com.mongodb.diagnostics.logging.JULLogger log
    信息: Opened connection [connectionId{localValue:2, serverValue:15}] to 192.168.71.193:27017
    { "_id" : { "$oid" : "59ec563f937ceb812c804c65"} , "code" : "110228" , "sheng" : "11" , "di" : "02" , "xian" : "28" , "name" : "密云县" , "level" : 3.0}
    { "_id" : { "$oid" : "59ec563f937ceb812c804c66"} , "code" : "110229" , "sheng" : "11" , "di" : "02" , "xian" : "29" , "name" : "延庆县" , "level" : 3.0}

[SouthEast]: /images/20220605/4618d27c554a44d6922e9529f0c49907.png