Closing the Database Connection - con.close()

JDBC Tutorials - Herong's Tutorial Examples

∟Microsoft JDBC Driver for SQL Server - sqljdbc42.jar

∟Closing the Database Connection - con.close()

This section describes how to close database connections.

When you obtained a connection object with DriverManager.getConnection() successfully, you can create statement objects and execute them with this connection object. But when you are done with this connection, you should close it to free resources associated this connection on the SQL server. To close a connection, you should call the close() method on this connection object.

The tutorial program below shows you how to call close() on a connection object. isClosed() method is called to verify the status of the connection object.

/* CloseConnection.java
 - Copyright (c) 2015, HerongYang.com, All Rights Reserved.
 */
import java.sql.*;
public class CloseConnection {
  public static void main(String [] args) {
    Connection con = null;
    try {

// Obtaining a connection to SQL Server
      con = DriverManager.getConnection(
          "jdbc:sqlserver://localhost\\SQLEXPRESS;"
        + "user=sa;password=HerongY@ng");

// Connection is ready to use
      DatabaseMetaData meta = con.getMetaData();
      System.out.println("Server name: " 
        + meta.getDatabaseProductName());
      System.out.println("Server version: "
        + meta.getDatabaseProductVersion());

// Closing the connection
      con.close();
      if (con.isClosed()) 
        System.out.println("Connection closed.");

    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

If you run this program, you will get:

C:\herong>\Progra~1\java\jdk1.8.0_45\bin\java 
   -cp .;\local\lib\sqljdbc42.jar CloseConnection

Server name: Microsoft SQL Server
Server version: 12.00.2000
Connection closed.

Last update: 2015.

Table of Contents

About This Book

JDBC (Java Database Connectivity) Introduction

JDK (Java SE) Installation

Installing and Running Java DB - Derby

Derby (Java DB) JDBC Driver

Derby (Java DB) JDBC DataSource Objects

Java DB (Derby) - DML Statements

Java DB (Derby) - ResultSet Objects of Queries

Java DB (Derby) - PreparedStatement

MySQL Installation on Windows

MySQL JDBC Driver (MySQL Connector/J)

MySQL - PreparedStatement

MySQL - Reference Implementation of JdbcRowSet

MySQL - JBDC CallableStatement

MySQL CLOB (Character Large Object) - TEXT

MySQL BLOB (Binary Large Object) - BLOB

Oracle Express Edition Installation on Windows

Oracle JDBC Drivers

Oracle - Reference Implementation of JdbcRowSet

Oracle - PreparedStatement

Oracle - JBDC CallableStatement

Oracle CLOB (Character Large Object) - TEXT

Oracle BLOB (Binary Large Object) - BLOB

Microsoft SQL Server 2005 Express Edition

►Microsoft JDBC Driver for SQL Server - sqljdbc42.jar

Installing Microsoft JDBC Driver for SQL Server

Loading Driver Class Automatically

Loading Driver Class with Class.forName()

DriverManager.getConnection() and Connection URL

Enabling TCP/IP with SQL Server Configuration Manager

Specifying Port Number in Connection URL

Instance Name Better than Port Number

Specifying Instance Name in Connection URL

►Closing the Database Connection - con.close()

Specifying Database Name in Connection URL

Incorrect Database Name in Connection URL

Creating Connections with DataSource Class

Microsoft JDBC Driver - Query Statements and Result Sets

Microsoft JDBC Driver - DatabaseMetaData Object

Microsoft JDBC Driver - DDL Statements

Microsoft JDBC Driver - DML Statements

SQL Server - PreparedStatement

SQL Server CLOB (Character Large Object) - TEXT

SQL Server BLOB (Binary Large Object) - BLOB

JDBC-ODBC Bridge Driver - sun.jdbc.odbc.JdbcOdbcDriver

JDBC-ODBC Bridge Driver - Flat Text Files

JDBC-ODBC Bridge Driver - MS Access

JDBC-ODBC Bridge Driver - MS SQL Server

Summary of JDBC Drivers and Database Servers

Additional Tutorial Notes to Be Added

Outdated Tutorials

PDF Printing Version