#.Java使用JDBC连接数据库的三种方式

/**

 * 1 在方法中固化连接参数

 * @return 数据库连接

 */

 public Connection getConnection() {

 Connection conn = null;

 try {

 Class.forName("com.mysql.jdbc.Driver");

 conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "");

 return conn;

 } catch (Exception e) {

 e.printStackTrace();

 }

 return null;

 }

 /**

 * 2 通过方法参数方式传递连接参数

 *

 * @return 数据库连接

 */

 public Connection getConnection(String driver, String url, String user, String password) {

 Connection conn = null;

 try {

 Class.forName(driver);

 conn = DriverManager.getConnection(url, user, password);

 return conn;

 } catch (Exception e) {

 e.printStackTrace();

 }

 return null;

 }

 /**

 * 3 通过properties配置文件的方式灵活配置连接参数，properties中的属性名固化

 *

 * @return 数据库连接

 */

 public Connection openConnection() {

 Connection conn = null;

 String driver = "";

 String url = "";

 String user = "";

 String password = "";

 Properties props = new Properties();

 try {

 props.load(this.getClass().getClassLoader()

 .getResourceAsStream("db.properties"));

 url = props.getProperty("mysql_url");

 driver = props.getProperty("mysql_driver");

 user = props.getProperty("mysql_user");

 password = props.getProperty("mysql_password");

 Class.forName(driver);

 conn = DriverManager.getConnection(url, user, password);

 return conn;

 } catch (Exception e) {

 e.printStackTrace();

 }

 return null;

 }