JDBC02

带配置文件的工具类

public class DBUtil {
	//声明成成员变量 方便使用
	private static Connection connection;
	private static String driverClass;
	private static String url;
	private static String username;
	private static String password;
static {
	readFile();
	//注册驱动
	try {
		Class.forName(driverClass);
	} catch (ClassNotFoundException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
	
}

//读文件的方法 
public static void readFile() {
	//读文件
		//类加载器 直接获取bin文件夹下的该文件
	InputStream inputStream = DBUtil.class.getClassLoader().getResourceAsStream("db.properties");
	Properties properties=new Properties();
	try {
		properties.load(inputStream);
		driverClass= properties.getProperty("driverClass");
		url= properties.getProperty("url");
		username= properties.getProperty("username");
		password= properties.getProperty("password");
	} catch (IOException e) {
		e.printStackTrace();
	
	}
	
}
//获取连接方法
public static Connection getConnection()  {
	try {
		connection=DriverManager.getConnection(url, username, password);
	} catch (SQLException e) {
		e.printStackTrace();
		throw new RuntimeException("获取连接失败");
	}
	return connection;
}
}
public class DBUtil {
	//声明成