mongodb的一个工具类

package cc.openwiki.utils
import cn.hutool.core.util.StrUtil;
import com.mongodb.DBCollection;
import com.mongodb.MongoClient;
import com.mongodb.ServerAddress;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import lombok.extern.slf4j.Slf4j;
import org.bson.Document;

import java.util.HashMap;
import java.util.Map;

@Slf4j
public class MongodbHelper {
    
    
    private static String host="10.19.128.134";
    private static String port="27017";
    
    
    public static Map<String,MongoCollection<Document>> maps= new HashMap<>();

    public static MongoClient mongoClient ;

    public static Map<String,MongoDatabase> dbMaps = new HashMap<>();

    public static MongoCollection<Document> getCollectionByDB(String db,String col){
        if(StrUtil.isEmpty(col)){
            log.info("获取连接错误");
            return null;
        }
        MongoCollection<Document> collection = maps.get(col);
        if(collection!=null){
            return collection;
        }
        synchronized(MongodbHelper.class){
            if (collection==null) {

                MongoDatabase md = getDB(db);
                
                collection = md.getCollection(col);
            }
            return collection;
        }
    }

    public static MongoCollection<Document> getCollection(String col){
        return getCollectionByDB("daily",col);
    }


    public static MongoDatabase getDB(String db){
        if(StrUtil.isEmpty(db)){
            log.info("获取连接错误");
            return null;
        }
        if(dbMaps.get(db)!=null){
            return dbMaps.get(db);
        }else {
            MongoDatabase md = getMongoClientInstace().getDatabase(db);
            dbMaps.put(db,md);
            return md;
        }
    }

    private static  MongoClient getMongoClientInstace() {  
        if(mongoClient == null){  
            synchronized (MongodbHelper.class) {  
                if(mongoClient == null){  
                    System.out.println("初始化mongoClient"+host+":"+port);
                    mongoClient = new MongoClient(new ServerAddress(host,Integer.parseInt(port)));  
                }  
            }  
        }  
        return mongoClient;  
    }  
    
    public static DBCollection getDBCollection(String col){
        return  mongoClient.getDB("daily").getCollection(col);

    }

    public static DBCollection getDBCollectionByDB(String db,String col){
        return  mongoClient.getDB(db).getCollection(col);

    }

    public void setHost(String host) {
        MongodbHelper.host = host;
    }

    public void setPort(String port) {
        System.out.println(port);
        MongodbHelper.port = port;
    }
}