package cn.liz.test;

import java.io.InputStream;
import java.sql.Connection;
import java.sql.Driver;
import java.sql.SQLException;
import java.util.Properties;
import org.junit.Test;

public class JBDCtest {
	
	/**
	 * 编写一个通用的方法, 在不修改源程序的情况下, 可以获取任何数据库的连接
	 * 解决方案: 把数据库驱动 Driver 实现类的全类名、url、user、password 放入一个
	 * 配置文件中, 通过修改配置文件的方式实现和具体的数据库解耦. 
	 * @throws Exception 
	 */
	
	public  Connection getConnection() throws Exception{
		String driverClass = null;
		String jdbcUrl = null;
		String user = null;
		String password = null;
		
		//读取类路径下的 jdbc.properties 文件
		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");
		
		//通过反射常见 Driver 对象. 
		Driver driver = 
				(Driver) Class.forName(driverClass).newInstance();
		
		Properties info = new Properties();
		info.put("user", user);
		info.put("password", password);
		
		//通过 Driver 的 connect 方法获取数据库连接. 
		Connection connection = driver.connect(jdbcUrl, info);
		
		return connection;
	}
	@Test
	public void testGetConnection() throws Exception{
		System.out.println(getConnection());
	}
}		

jdbc.properties配置文件：

#driver=oracle.jdbc.driver.OracleDriver
#jdbcUrl=jdbc:oracle:thin:@localhost:1521:orcl
#user=scott
#password=java
driver=com.mysql.jdbc.Driver
jdbcUrl=jdbc:mysql://localhost:3306/test
user=root
password=