如何在jsp中匹配来自数据库的字段值?
我在jsp中注册了两个字段用户名和密码,我将这些字段插入数据库。在插入之前,我想检查用户名是否已经存在,然后不要在db中插入用户名,并打印任何有意义的完整消息 这是我的密码:如何在jsp中匹配来自数据库的字段值?,jsp,jdbc,Jsp,Jdbc,我在jsp中注册了两个字段用户名和密码,我将这些字段插入数据库。在插入之前,我想检查用户名是否已经存在,然后不要在db中插入用户名,并打印任何有意义的完整消息 这是我的密码: String user = request.getParameter("user"); String pass = request.getParameter("pass"); try{ Class.forName("com.mysql.jdbc.Driver"); Connection cn = D
String user = request.getParameter("user");
String pass = request.getParameter("pass");
try{
Class.forName("com.mysql.jdbc.Driver");
Connection cn = DriverManager.getConnection("jdbc:mysql://localhost:3306/Court","root","Dan@1234");
PreparedStatement ps=cn.prepareStatement("insert into Councel values(?,?)");
ps.setString(1,user);
ps.setString(2,pass);
int i=ps.executeUpdate();
if(i==1)
}
catch(Exception e)
{
out.println(e.toString());
}
String user = request.getParameter("user");
String pass = request.getParameter("pass");
try{
Class.forName("com.mysql.jdbc.Driver");
Connection cn = DriverManager.getConnection("jdbc:mysql://localhost:3306/Court","root","Dan@1234");
PreparedStatement ps0=cn.prepareStatement("Select uname from Councel where uname=?");
ps0.setString(1,user);
ResultSet rs=ps0.executeQuery();
if(rs.next())
{
//User already exists
}
else{
PreparedStatement ps=cn.prepareStatement("insert into Councel values(?,?)");
ps.setString(1,user);
ps.setString(2,pass);
int i=ps.executeUpdate();
if(i==1){}
}
}
catch(Exception e)
{
out.println(e.toString());
}