MongoDB connection method learning

MongoDB needs to be used in the project. According to the introduction, the connection pool idea of MongoDB can be used to maintain only one instance,

Refer to Region.

Package CN. CNIC. jingshao. mongodbapp. util; import java.net. unknownhostexception; import COM. mongoDB. DB; import COM. mongoDB. mongo; import COM. mongoDB. except exception; import COM. mongoDB. optional options; public class mongodbutil {// The only Mongo instance private Mongo; // use the singleton mode private mongodbutil () {} Private Static class innerholder {static final includbutil instance = new includbutil ();} public static includbutil getinst Ance () {return innerholder. instance;}/*** initialize MongoDB connection * @ throws unknownhostexception * @ throws unknown exception */Public void Init () throws unknownhostexception, except exception {int poolsize = configutil. getinstance (). getpoolsize (); // Number of connections read from the configuration file if (poolsize =-1) {poolsize = 10000;} system. setproperty ("Mongo. poolsize ", String. valueof (poolsize); If (this. mongo = NULL) {// system. out. println ("1st init m Ongo instance "); // Mongo instance is instantiated only once // read the server address and port number from the configuration file string serverip = configutil. getinstance (). getserverip (); int portnum = configutil. getinstance (). getportnum (); Mongo = new Mongo (serverip, portnum); Optional options = Mongo. getaskoptions (); options. autoconnectretry = true; options. connectionsperhost = poolsize ;}}/*** get dB instance * @ Param dbname * @ return */Public dB getdb (string dbname) {If (dbname! = NULL &&! Dbname. equals ("") {return this. mongo. getdb (dbname);} else {return NULL;}/*** close MongoDB */Public void close () {If (this. mongo! = NULL) {This. Mongo. Close (); this. Mongo = NULL ;}}}