Java mongodb api疑问之MongoCollection与DBCollection

import com.mongodb.BasicDBObject;
import com.mongodb.DBCollection;
import com.mongodb.DBObject;
import com.mongodb.MongoClient;import java.util.ArrayList;
import java.util.Date;
import java.util.List;public class MonConnections { //Mongo db 批量插入数据
private static MongoClient mongoClient = new MongoClient("127.0.0.1", 27017);
private static long count = 2000000;
public static MongoClient getClient(){
return mongoClient;
} public static void main(String[] args){
List<DBObject> list = new ArrayList<>();
DBCollection collection = mongoClient.getDB("test").getCollection("book"); for (int i = 0; i < 2200000; i++){
DBObject object = new BasicDBObject();
object.put("id", String.valueOf(count));
Date date = new Date();
object.put("add_time", date);
object.put("title", "mongo"+count++);
list.add(object);
if (i != 0 && i %10000 == 0){
System.out.println("插入" + " " + i + "本书");
collection.insert(list);
list.clear();
}
} }
}

@Test
public void getCollection( ){
try{
// 连接到 mongodb 服务
MongoClient mongoClient = new MongoClient( "localhost" , 27017 );
// 连接到数据库
MongoDatabase mongoDatabase = mongoClient.getDatabase("mongodbname");
System.out.println("Connect to database successfully"); MongoCollection<Document> collection = mongoDatabase.getCollection("javatest");
//DBCollection
System.out.println("集合 test 选择成功");
}catch(Exception e){
System.err.println( e.getClass().getName() + ": " + e.getMessage() );
}
}