mongodb 连接池

 //MyMongo.js

1 var mongodb = require ( 'mongodb' );

2

3 function MyMongo ( host , port , dbname ) {

4 this . host = host ;

5 this . port = port ;

6 this . dbname = dbname ;

7

8 this . server = new mongodb . Server ( this . host , this . port ,{ auto_reconnect : true , safe : true });

9

10 this . db_connector = new mongodb . Db ( this . dbname , this . server ,{ safe : true });

//加上{safe:true}之后就不会提示

//Please ensure that you set the default write concern for the database by setting one of the options

11

12 var self = this ;

13

14 this . db = undefined ;

15 this . queue = [];

16

17 this . db_connector . open ( function ( err , db ) {

18 if ( err ) {

19 console . log ( err );

20 return ;

21 }

22 self . db = db ;

23 for ( var i = 0 ; i < self . queue . length ; i ++ ) {

24 var collection = new mongodb . Collection ( self . db , self . queue [ i ]. cn ); //cn collectionName

25 self . queue [ i ]. cb ( collection );

26 }

27 self . queue = [];

28

29 });

30 }

31 exports . MyMongo = MyMongo ;

32

33 MyMongo . prototype . query = function ( collectionName , callback ) {

34 if ( this . db != undefined ) {

35 var collection = new mongodb . Collection ( this . db , collectionName );

36 callback ( collection );

37 return ;

38 }

39 this . queue . push ({ "cn" : collectionName , "cb" : callback });

40 }

//config.js

1 var mongo = require ( './lib/MyMongo.js' ). MyMongo ;

2

3 var db = new mongo ( 'localhost' , 27017 , 'operation' );

4

5 exports = module . exports = {

6 db_name : 'operation' ,

7 db : db

8

9 };

//use.js

1 var config = require ( 'config.js' );

2

3 var db = config . db ;

4

7 //nodejs下的col集合

8 var COL = 'col' ;

9

10 db . query ( COL , function ( collection ) {

11 collection . insert ({ a : 1 , b : 2 , c : 3 }, function ( err , docs ) {

12 console . log ( "First:\n" , docs );

13 });

14 });

15

16

17 db . query ( COL , function ( collection ) {

18 collection . find ({}, {

19 limit : 10

20 }). toArray ( function ( err , docs ) {

21 console . log ( "\nSecond:\n" , docs );

22 });

23 });