Obtain the database connection through Driver and the driver database connection

Obtain the database connection through Driver and the driver database connection

Take a look at the file. There is a properties configuration file under the current package, and there is a lib folder under the root directory, which contains the mySql driver jar package

Driver: an interface. The database vendor must provide the implemented interface to obtain the database connection. You can use the implementation Class Object of the Driver to obtain the database connection.
* 1. Add the mySql driver
* 1.1 decompress mysql-connector-java-5.1.39.zip 1.2 create a lib directory in the current project 1.3
* Copy the mysql-connector-java-5.1.39-bin.jar to the lib directory, right-click 1.4, buildPath, add
* Add buildPath to the class path

The first method is to directly obtain the database connection without the configuration file.

1 @ Test 2 public void testDriver () throws Exception {3 // 1. create a Driver implementation Class Object 4 Driver driver = new com. mysql. jdbc. driver (); 5 // 2. prepare the basic information for connecting to the database, url, user, password 6 String url = "jdbc: mysql: // localhost: 3306/test"; 7 8 Properties info = new Properties (); 9 info. put ("user", "root"); 10 info. put ("password", "123456"); 11 12 // 3. call connect (url, info) of the Driver interface to obtain the database Connection 13 connection Connection = driver. connect (url, info); 14 15 System. out. println (connection); // com. mysql. jdbc. JDBC4Connection @ 73f71216}

 

To make the program decoupled and more generic, use the following solution:

Compile a common method. without modifying the source program, you can obtain the connection solution of any database.
The full class name, url, user, and password of the implementation class are put into a configuration file, which is decoupled from the specific database by modifying the configuration file.

Code:

Public Connection getConnection () throws Exception {String driverClass = null; String jdbcUrl = null; String user = null; String password = null; // read jdbc under the class path. properties file InputStream in = getClass (). getClassLoader (). getResourceAsStream ("jdbc. properties "); Properties properties = new Properties (); properties. load (in); driverClass = properties. getProperty ("driver"); jdbcUrl = properties. getProperty ("jdbcUrl"); user = properties. getProperty ("user"); password = properties. getProperty ("password"); // creates a Driver object through reflection. driver driver = (Driver) Class. forName (driverClass ). newInstance (); Properties info = new Properties (); info. put ("user", user); info. put ("password", password); // obtain the database connection through the connect Method of the Driver. connection connection = driver. connect (jdbcUrl, info); return connection;} @ Test public void testGetConnection () throws Exception {System. out. println (getConnection (); // com. mysql. jdbc. JDBC4Connection @ 1556938}

The properties file is as follows:

#driver=oracle.jdbc.driver.OracleDriver#jdbcUrl=jdbc:oracle:thin:@localhost:1521:orcl#user=scott#password=javadriver=com.mysql.jdbc.DriverjdbcUrl=jdbc:mysql://localhost:3306/testuser=rootpassword=123456

In this way, if you want to connect to other databases, you only need to modify this file without modifying the code.