DriverManager 鏈接不一樣的鏈接池

public class DriverManager extends Object

The basic service for managing a set of JDBC drivers.
NOTE: The DataSource interface, new in the JDBC 2.0 API, provides another way to connect to a data source. The use of a DataSource object is the preferred means of connecting to a data source.

As part of its initialization, the DriverManager class will attempt to load the driver classes referenced in the "jdbc.drivers" system property. This allows a user to customize the JDBC Drivers used by their applications. For example in your ~/.hotjava/properties file you might specify:

jdbc.drivers=foo.bah.Driver:wombat.sql.Driver:bad.taste.ourDriver

The DriverManager methods getConnection and getDrivers have been enhanced to support the Java Standard Edition Service Provider mechanism. JDBC 4.0 Drivers must include the file META-INF/services/java.sql.Driver. This file contains the name of the JDBC drivers implementation of java.sql.Driver. For example, to load the my.sql.Driver class, the META-INF/services/java.sql.Driver file would contain the entry:

my.sql.Driver

Applications no longer need to explictly load JDBC drivers using Class.forName(). Existing programs which currently load JDBC drivers using Class.forName() will continue to work without modification.

When the method getConnection is called, the DriverManager will attempt to locate a suitable driver from amongst those loaded at initialization and those loaded explicitly using the same classloader as the current applet or application.

Starting with the Java 2 SDK, Standard Edition, version 1.3, a logging stream can be set only if the proper permission has been granted. Normally this will be done with the tool PolicyTool, which can be used to grant permission java.sql.SQLPermission "setLog".

public static Connection getConnection(String url,
                       String user,
                       String password)
                                throws SQLException

Attempts to establish a connection to the given database URL. The DriverManager attempts to select an appropriate driver from the set of registered JDBC drivers.

Parameters:

url - a database url of the form jdbc:subprotocol:subname

user - the database user on whose behalf the connection is being made

password - the user's password

Returns:

a connection to the URL

Throws:

SQLException - if a database access error occurs