增加用户名

首页根据用户名查询出来结果:

?Class.forName("com.mysql.jdbc.Driver");?Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/spring", "root", "ocsoft");??String sqlQuery = "select count(*) from user where username= ?";?PreparedStatement psQuery = conn.prepareStatement(sqlQuery);?psQuery.setString(1,username);?ResultSet rs = psQuery.executeQuery();?rs.next();?int count = rs.getInt(1);//拿到字段值?if (count > 0) {??response.sendRedirect("registerFail.jsp");??psQuery.close();??conn.close();??return;?}

?如果查询出来的值大于零...表明用户名已经存在了.否则反之....添加该用户

String sql = "insert into user (username,password) values(?,?)";PreparedStatement ps = conn.prepareStatement(sql);ps.setString(1,username);ps.setString(2,password);ps.executeUpdate();ps.close();conn.close();response.sendRedirect("registerSuccess.jsp");

?

总结:以后编程一般用这种思想编