Java operation mongodb base of of query sort output list
- 2020-04-01 02:39:41
- OfStack
package com.infomorrow.webroot;
import java.util.List;
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.MongoClient;
public class test_mongodb {
public static void main(String args[]) throws Exception {
MongoClient mongoClient = new MongoClient( "127.0.0.1" , 27017 );//Establish a connection
DB get_db_credit = mongoClient.getDB("credit_2");//The database name
DBCollection collection = get_db_credit.getCollection("report");//The collection name corresponds to the table name in mysql
BasicDBObject filter_dbobject = new BasicDBObject();
//Set up a query condition, if there are other conditions, similar to write
//For example :version=3,filter_dbobject. Put ("version", 3),mongod distinguishes between String and Integer, so be careful with "3"! = 3
filter_dbobject.put("user_id", "10065716153075");
//Now I'm going to do the query, I'm going to set limit, I'm going to do 10 pieces of data, I'm going to do the sort (mysql Derby) and I'm going to do a BasicDBObject, -1 is the reverse order
DBCursor cursor = collection.find(filter_dbobject).limit(10).sort(new BasicDBObject("create_time",-1));
//Output the result set as a list type
List<DBObject> list = cursor.toArray();
System.out.println(list.size());//The length of the list
System.err.println(cursor.count());//The number of calculated results, similar to the (mysql count() function), is not affected by limit
//Traversing the result set
while(cursor.hasNext()) {
System.out.println(cursor.next());
}
}
}