1. 加载驱动2创建连接

   
   

   public static Connection getConn() throws SQLException,

   ClassNotFoundException {

   Class.forName("com.mysql.jdbc.Driver");//1

   return DriverManager

   .getConnection(

   "jdbc:mysql://localhost:3306/bookstore?useUnicode=true&characterEncoding=utf-8",

   "root", "password");//2

   }

3执行语句

String sql = "select authorise from user where username=? and password = ?";

pst=con.prepareStatement(sql);

pst.setString(1, name);

pst.setString(2, password);

rs = pst.executeQuery();//查询用这条

String sql="update book set bookname=?,price=? where id=?";

pst=con.prepareStatement(sql);

pst.setString(1, book.getBookname());

pst.setFloat(2, book.getPrice());

pst.setInt(3,book.getId());

count=pst.executeUpdate();//增删改用这条

4得到结果

while(rs.next()!=null){}

5关闭连接

if (rs != null) {

rs.close();

}

if (pst != null) {

pst.close();

}

if (con != null) {

con.close();

}