读取配置文件中数据库设置信息来创建connection对象

package com.atguigu.jdbc;

import java.io.IOException;
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 JDBCTest {

/**
* 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、userpassword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 ClassNotFoundException
* @throws IllegalAccessException
* @throws InstantiationException
* @throws SQLException
* @throws IOException
*/

public Connection getConnection() throws InstantiationException, IllegalAccessException, ClassNotFoundException, SQLException, IOException{
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("driverClass");
jdbcUrl=properties.getProperty("jdbcUrl");
user=properties.getProperty("user");
password=properties.getProperty("password");
//通过反射创建Driver对象
Driver driver=(Driver)Class.forName(driverClass).newInstance();
Properties info=new Properties();
info.setProperty("user", user);
info.setProperty("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 InstantiationException, IllegalAccessException, ClassNotFoundException, SQLException, IOException{
System.out.println(getConnection());
}

}