数据库跨平台的实现

说明：

         便于随时切换数据库

步骤：

         先创建dbconfig.properties，再编写DBUtils工具类，最后编写DBTest测试类。

参考代码如下：

/**
 *dbconfig.properties
 */
#mysql
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/ooo
user=root
password=root
#oracle
#driver=oracle.jdbc.driver.OracleDriver
#url=jdbc:oracle:thin:@localhost:1521:orcl
#user=scott
#password=tiger

/**
 *DBUtils.class
 */
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.util.Properties;

public class DbUtils {
	private static String driver;
	private static String url;
	private static String username;
	private static String password;
	private static ThreadLocal<Connection> tl = new ThreadLocal<>();
	static {
		InputStream is = DbUtils.class.getClassLoader().getResourceAsStream("dbconfig.properties");
		Properties prop = new Properties();
		try {
			prop.load(is);
			driver = prop.getProperty("driver");
			url = prop.getProperty("url");
			username = prop.getProperty("user");
			password = prop.getProperty("password");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (is != null) {
				try {
					is.close();
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		}
	}

/**
 *获取连接
 */
	public static Connection getConnection() {
		Connection con = null;
		try {
			Class.forName(driver);
			con = DriverManager.getConnection(url, username, password);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return con;
	}

/**
 *获取事务连接
 */
	public static Connection getTransactionConnection() {
		Connection con = null;
		con = tl.get();
		if (con == null) {
			con = getConnection();
			tl.set(con);
		}
		return con;
	}

/**
 *关闭事务连接
 */
	public static void closeTransactionConnection() {
		Connection con = tl.get();
		if (con != null) {
			tl.remove();
			try {
				con.close();
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
	}
}

/**
 *测试类
 */
import java.sql.Connection;

public class DBTest {
	public static void main(String[] args) {
		Connection con=DbUtils.getConnection();
		System.out.println("con="+con);
	}
}

运行结果如下：