データベースドライバの登録の3つの方法

ダイレクトレジストリドライバ:

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

//  
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.DriverManager経由registerDriver()登録ドライバ

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

//  
String url="jdbc:mysql://localhost:3306/test";
		
		//extends Hashtable<Object,Object>
		Properties info=new Properties();
		
		info.setProperty("user", "root");
		info.setProperty("password", "123");
		
		//           ，  mysql            
		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.新規メーカー実現com.mysql.jdbc.Driverクラス

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

//  ：
try {
			//com.mysql.jdbc.Driver Java.sql.Driver      
			java.sql.Driver driver=new com.mysql.jdbc.Driver();
			
			//         URL
			String url="jdbc:mysql://localhost:3306/test";
			
			//extends Hashtable<Object,Object>
			Properties info=new Properties();
			
			info.setProperty("user", "root");
			info.setProperty("password", "123");
			
			//  connection  
			Connection con=driver.connect(url, info);
			
			System.out.println(con.toString());
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

ドライバ登録に成功した後は、基本的にDriverManager.getConnection(url,user,password)は、データベースの接続を取得します.

try{
       Class.forName("com.mysql.jdbc.Driver");//       
       String url="jdbc:mysql://localhost:3306/databasename";//        
       Connection conn=DriverManager.getConnection(url,"username","password");
       Statement stmt=conn.createStatement();
       ResultSet rs=stmt.executeQuery("select * from tablename");
       while(rs.next()){//         
            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("           ！");
}catch(SQLException e){
    e.printStackTrace();
}

//         
try{
       System.setProperty("jdbc.driver","com.mysql.jdbc.Driver");//           
       String url="jdbc:mysql://localhost:3306/databasename";//        
       Connection conn=DriverManager.getConnection(url,"username","password");
       Statement stmt=conn.createStatement();
       ResultSet rs=stmt.executeQuery("select * from tablename");
       while(rs.next()){//         
            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();
}

//            ，     db jdbc  ，3           lib
try{
       new com.mysql.jdbc.Driver();//  driver  ，       
       String url="jdbc:mysql://localhost:3306/databasename";//        
       Connection conn=DriverManager.getConnection(url,"username","password");
       Statement stmt=conn.createStatement();
       ResultSet rs=stmt.executeQuery("select * from tablename");
       while(rs.next()){//         
            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();
}