1.比较常用

try{

Class.forName("com.mysql.jdbc.Driver");//加载数据库驱动

String url="jdbc:mysql://localhost:3306/databasename";//数据库连接子协议

//databasename:需要连接的数据库名字；username：数据库登录用户名；password：数据库登录密码；

Connection conn=DriverManager.getConnection(url,"root","psw");

Statement stmt=conn.createStatement();

ResultSet rs=stmt.executeQuery("select * from tablename");

while(rs.next()){//不断指向下一条记录

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("找不到指定的驱动程序类！");

}catch(SQLException e){

e.printStackTrace();

}

2.通过系统的属性设置

try{

System.setProperty("jdbc.driver","com.mysql.jdbc.Driver");

//系统属性指定数据库驱动

//数据库连接子协议

Connection conn=DriverManager.getConnection(url,"root","psw");

Statement stmt=conn.createStatement();

ResultSet rs=stmt.executeQuery("select * from tablename");

while(rs.next()){//不断指向下一条记录

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();

}

3、注册相应的db的jdbc驱动，在编译时需要导入对应的lib

try{

new com.mysql.jdbc.Driver();//创建driver对象，加载数据库驱动

String url="jdbc:mysql://localhost:3306/databasename";

//数据库连接子协议

Connection conn=DriverManager.getConnection(url,"root","psw");

Statement stmt=conn.createStatement();

ResultSet rs=stmt.executeQuery("select * from tablename");

while(rs.next()){//不断指向下一条记录

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();

}

注意：  在使用Connection的时候，JSP中出现：Connection cannot be resolved to a type的报错，这是由于没有导入Connect这个类。  在jsp的开始导入jar：