Java implementation of mongodb database connection pool

MongoDB is a product between relational database and non-relational database. The file storage format is BSON (an extension of JSON). Here, it is mainly introduced that Java realizes MongoDB connection pool by using mongo-2.7.3.jar package.

Database connection pool configuration parameters:

  
package cn.lulei.mongo.pool; 
 
public class MongoConfig { 
  
 private static String userName;//The user name
 private static String pwd;//password
 private static String[] host;//The host address
 private static int[] port;//Port address
 private static String dbName;//The database name
 private static int connectionsPerHost = 20;//Maximum number of connections per host
 private static int threadsAllowedToBlockForConnectionMultiplier = 10;//Number of thread queues
 private static boolean authentication = false;//Whether authentication is required
  
 public static String getUserName() { 
  return userName; 
 } 
 public static void setUserName(String userName) { 
  MongoConfig.userName = userName; 
 } 
 public static String getPwd() { 
  return pwd; 
 } 
 public static void setPwd(String pwd) { 
  MongoConfig.pwd = pwd; 
 } 
 public static String[] getHost() { 
  return host; 
 } 
 public static void setHost(String[] host) { 
  MongoConfig.host = host; 
 } 
 public static int[] getPort() { 
  return port; 
 } 
 public static void setPort(int[] port) { 
  MongoConfig.port = port; 
 } 
 public static String getDbName() { 
  return dbName; 
 } 
 public static void setDbName(String dbName) { 
  MongoConfig.dbName = dbName; 
 } 
 public static int getConnectionsPerHost() { 
  return connectionsPerHost; 
 } 
 public static void setConnectionsPerHost(int connectionsPerHost) { 
  MongoConfig.connectionsPerHost = connectionsPerHost; 
 } 
 public static int getThreadsAllowedToBlockForConnectionMultiplier() { 
  return threadsAllowedToBlockForConnectionMultiplier; 
 } 
 public static void setThreadsAllowedToBlockForConnectionMultiplier( 
   int threadsAllowedToBlockForConnectionMultiplier) { 
  MongoConfig.threadsAllowedToBlockForConnectionMultiplier = threadsAllowedToBlockForConnectionMultiplier; 
 } 
 public static boolean isAuthentication() { 
  return authentication; 
 } 
 public static void setAuthentication(boolean authentication) { 
  MongoConfig.authentication = authentication; 
 } 
} 

Database connection pool management class:

  
package cn.lulei.mongo.pool; 
 
import java.util.ArrayList; 
import java.util.List; 
 
import com.mongodb.DB; 
import com.mongodb.DBCollection; 
import com.mongodb.Mongo; 
import com.mongodb.MongoOptions; 
import com.mongodb.ReadPreference; 
import com.mongodb.ServerAddress; 
 
public class MongoManager { 
  
 private static Mongo mongo; 
 private DB db; 
  
 static{ 
  init(); 
 } 
  
  
 public MongoManager(String dbName, String userName, String pwd) { 
  if (dbName == null || "".equals(dbName)) { 
   throw new NumberFormatException("dbName is null"); 
  } 
  db = mongo.getDB(dbName); 
  if(MongoConfig.isAuthentication() && !db.isAuthenticated()){ 
   if (userName == null || "".equals(userName)) { 
    throw new NumberFormatException("userName is null"); 
   } 
   if (pwd == null || "".equals(pwd)) { 
    throw new NumberFormatException("pwd is null"); 
   } 
   db.authenticate(userName, pwd.toCharArray()); 
  } 
 } 
  
  
 public MongoManager() { 
  this(MongoConfig.getDbName(), MongoConfig.getUserName(), MongoConfig.getPwd()); 
 } 
  
  
 public DBCollection getDBCollection(String tableName) { 
  return db.getCollection(tableName); 
 } 
  
  
 private static void init() { 
  if (MongoConfig.getHost() == null || MongoConfig.getHost().length == 0) { 
   throw new NumberFormatException("host is null"); 
  } 
  if (MongoConfig.getPort() == null || MongoConfig.getPort().length == 0) { 
   throw new NumberFormatException("port is null"); 
  } 
  if (MongoConfig.getHost().length != MongoConfig.getPort().length) { 
   throw new NumberFormatException("host's length is not equals port's length"); 
  } 
  try { 
   //Service list
   List<ServerAddress> replicaSetSeeds = new ArrayList<ServerAddress>(); 
   for (int i = 0; i < MongoConfig.getHost().length; i++) { 
    replicaSetSeeds.add(new ServerAddress(MongoConfig.getHost()[i], MongoConfig.getPort()[i])); 
   } 
   //Connection pool parameter Settings
   MongoOptions options = new MongoOptions(); 
   options.connectionsPerHost = MongoConfig.getConnectionsPerHost(); 
   options.threadsAllowedToBlockForConnectionMultiplier = MongoConfig.getThreadsAllowedToBlockForConnectionMultiplier(); 
   mongo = new Mongo(replicaSetSeeds, options); 
   //Readable from the server
   mongo.setReadPreference(ReadPreference.SECONDARY); 
  } catch (Exception e){ 
   e.printStackTrace(); 
  } 
 } 
} 

Let's take a look at how to use this connection pool through a simple test class

  
package cn.lulei.mongo.test; 
 
import cn.lulei.mongo.pool.MongoConfig; 
import cn.lulei.mongo.pool.MongoManager; 
 
public class Test { 
 
 public static void main(String[] args) { 
  // TODO Auto-generated method stub 
  String[] host = {"127.0.0.1"}; 
  int[] port = {27001}; 
  MongoConfig.setHost(host); 
  MongoConfig.setPort(port); 
  MongoConfig.setDbName("novel"); 
  MongoManager mongoManager = new MongoManager(); 
  mongoManager.getDBCollection("chapter"); 
 } 
 
} 

When using the above management class, you just need to initialize the MongoConfig class. For an instance of class MongoManager, you can either use the configuration of MongoConfig or set parameters by yourself. Every time you get a DBCollection, you just need to call the getDBCollection(String tableName) method.

That's all for this article, and I hope it will help you learn Java programming.