註冊數據庫驅動的三種方式

1. 直接註冊驅動：
   

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

//實現
try {
			Class.forName("com.mysql.jdbc.Driver");
			String url="jdbc:mysql://localhost:3306/test";
			Connection con= DriverManager.getConnection(url, "root", "123");
			System.out.println(con);
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

2.經過DriverManager.registerDriver()註冊驅動

DriverManager.registerDriver(new com.mysql.jdbc.Driver());

//實現
String url="jdbc:mysql://localhost:3306/test";
		
		//extends Hashtable<Object,Object>
		Properties info=new Properties();
		
		info.setProperty("user", "root");
		info.setProperty("password", "123");
		
		//向驅動管理器註冊驅動 ，是把mysql驅動類的對象放置到集合中
		try {
			DriverManager.registerDriver(new com.mysql.jdbc.Driver());
			Connection con=DriverManager.getConnection(url, info);
			System.out.println(con);
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

3.新建廠商實現的com.mysql.jdbc.Driver類

java.sql.Driver driver=new com.mysql.jdbc.Driver();

//實現：
try {
			//com.mysql.jdbc.Driver是Java.sql.Driver的廠商的實現
			java.sql.Driver driver=new com.mysql.jdbc.Driver();
			
			//要鏈接到的數據庫的URL
			String url="jdbc:mysql://localhost:3306/test";
			
			//extends Hashtable<Object,Object>
			Properties info=new Properties();
			
			info.setProperty("user", "root");
			info.setProperty("password", "123");
			
			//獲取connection鏈接
			Connection con=driver.connect(url, info);
			
			System.out.println(con.toString());
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

驅動註冊成功以後，基本上能夠經過DriverManager.getConnection(url,user,password)來獲取數據庫的鏈接

try{
       Class.forName("com.mysql.jdbc.Driver");//加載數據庫驅動
       String url="jdbc:mysql://localhost:3306/databasename";//數據庫鏈接子協議
       Connection conn=DriverManager.getConnection(url,"username","password");
       Statement stmt=conn.createStatement();
       ResultSet rs=stmt.executeQuery("select * from tablename");
       while(rs.next()){//不斷指向下一條記錄
            System.out.println("DeptNo:"+rs.getInt(1));
            System.out.println("\tDeptName:"+rs.getString(2));
            System.out.println("\tLOC:"+rs.getString(3));
}         
    rs.close();
    stmt.close();
    conn.close();
}catch(ClassNotFoundException e){
   System.out.println("找不到指定的驅動程序類！");
}catch(SQLException e){
    e.printStackTrace();
}

//經過系統的屬性設置
try{
       System.setProperty("jdbc.driver","com.mysql.jdbc.Driver");//系統屬性指定數據庫驅動
       String url="jdbc:mysql://localhost:3306/databasename";//數據庫鏈接子協議
       Connection conn=DriverManager.getConnection(url,"username","password");
       Statement stmt=conn.createStatement();
       ResultSet rs=stmt.executeQuery("select * from tablename");
       while(rs.next()){//不斷指向下一條記錄
            System.out.println("DeptNo:"+rs.getInt(1));
            System.out.println("\tDeptName:"+rs.getString(2));
            System.out.println("\tLOC:"+rs.getString(3));
}         
    rs.close();
    stmt.close();
    conn.close();
}catch(SQLException e){
    e.printStackTrace();
}

//看起來比較直觀的一種方式，註冊相應的db的jdbc驅動，3在編譯時須要導入對應的lib
try{
       new com.mysql.jdbc.Driver();//建立driver對象，加載數據庫驅動
       String url="jdbc:mysql://localhost:3306/databasename";//數據庫鏈接子協議
       Connection conn=DriverManager.getConnection(url,"username","password");
       Statement stmt=conn.createStatement();
       ResultSet rs=stmt.executeQuery("select * from tablename");
       while(rs.next()){//不斷指向下一條記錄
            System.out.println("DeptNo:"+rs.getInt(1));
            System.out.println("\tDeptName:"+rs.getString(2));
            System.out.println("\tLOC:"+rs.getString(3));
}         
    rs.close();
    stmt.close();
    conn.close();
}catch(SQLException e){
    e.printStackTrace();
}