Establishes a connection from the given database URL in the form of: jdbc:
subprotocol:
subname
Establishes a connection from the given database URL and a Properties object which includes additional information such as user and password.
Establishes a connection from the given database URL, user and password.
As you notice, all methods require a database URL which is a string in a special format that contains information about the database to connect to, such as server name, database name, user, password… Database URL is specific to a particular database system. Following is an example of a database URL for MySQL:jdbc:mysql://localhost:3306/test
where localhost is server name, 3306 is port number, and test is database name.All the methods return a Connection object which is used for making SQL queries to the connected database.The following code examples illustrate establishing connection to a MySQL database. Follow this tutorial to download JDBC driver for MySQL.import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; public class ConnectJDBC3 { public static void main(String[] args) { String databaseURL = "jdbc:mysql://localhost:3306/test"; String user = "user"; String password = "password"; Connection conn = null; try { Class.forName("com.mysql.jdbc.Driver"); conn = DriverManager.getConnection(databaseURL, user, password); if (conn != null) { System.out.println("Connected to the database"); } } catch (ClassNotFoundException ex) { System.out.println("Could not find database driver class"); ex.printStackTrace(); } catch (SQLException ex) { System.out.println("An error occurred. Maybe user/password is invalid"); ex.printStackTrace(); } finally { if (conn != null) { try { conn.close(); } catch (SQLException ex) { ex.printStackTrace(); } } } } }
import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; public class DBConnect1 { public static void main(String[] args) { String databaseURL = "jdbc:mysql://localhost:3306/test?user=root&password=root123"; Connection conn = null; try { conn = DriverManager.getConnection(databaseURL); if (conn != null) { System.out.println("Connected to the database"); } } catch (SQLException ex) { System.out.println("An error occurred. Maybe user/password is invalid"); ex.printStackTrace(); } finally { if (conn != null) { try { conn.close(); } catch (SQLException ex) { ex.printStackTrace(); } } } } }Example 2: getConnection(String url, Properties info) :In this way, we put the user and password in a Properties object:
import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.util.Properties; public class DBConnect2 { public static void main(String[] args) { String databaseURL = "jdbc:mysql://localhost:3306/test"; Connection conn = null; try { Properties props = new Properties(); props.put("user", "root"); props.put("password", "root123"); conn = DriverManager.getConnection(databaseURL, props); if (conn != null) { System.out.println("Connected to the database"); } } catch (SQLException ex) { System.out.println("An error occurred. Maybe user/password is invalid"); ex.printStackTrace(); } finally { if (conn != null) { try { conn.close(); } catch (SQLException ex) { ex.printStackTrace(); } } } } }Example 3: getConnection(String url, String user, String password)In this way, we supply the user and password directly into the method’s arguments:
import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; public class DBConnect3 { public static void main(String[] args) { String databaseURL = "jdbc:mysql://localhost:3306/test"; String user = "root"; String password = "root123"; Connection conn = null; try { conn = DriverManager.getConnection(databaseURL, user, password); if (conn != null) { System.out.println("Connected to the database"); } } catch (SQLException ex) { System.out.println("An error occurred. Maybe user/password is invalid"); ex.printStackTrace(); } finally { if (conn != null) { try { conn.close(); } catch (SQLException ex) { ex.printStackTrace(); } } } } }NOTE: Since Java 1.7, you can use the try-with-resources statement to make connection to database without explicitly closing the connection, for example:
public void connectDatabase(String url, String user, String password) { try (Connection conn = DriverManager.getConnection(url, user, password)) { if (conn != null) { System.out.println("Connected to the database"); } } catch (SQLException ex) { System.out.println("An error occurred. Maybe user/password is invalid"); ex.printStackTrace(); } }The try-with-resources statement automatically close the resource (database connection) for you.That's some Java code examples for connecting to a database with JDBC.