trying to understand JSP

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October 15th, 2001, 02:22 PM

coach

Contributing User

Join Date: Oct 2001

Posts: 94

Time spent in forums: 51 m 10 sec
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trying to understand JSP

I've programmed using PHP and now I have a project that requires JSP. While there are some good similarities between PHP and JSP - I am finding some common tasks very tedious and wondered if someone might point me in the right direction.

I am trying to authenticate using MySQL - and while everything is ok so far - I get errors with the following code.

Code:

//user has entered email and password 

<%@ page language="java" import="java.sql.*" %>


<% 
  if (request.getParameter("email").length() == 0 ||
      request.getParameter("password").length() == 0) { 
%>

     <jsp:forward page="admin.jsp" >
     <jsp:param name="errorMsg" 
     value="You must enter an email address and Password!" />
     </jsp:forward>

<% } %>

<%
String conn;

Class.forName("org.gjt.mm.mysql.Driver");

// create connection string
conn = "jdbc:mysql://localhost/profile?user=user&password=pass";

// pass database parameters to JDBC driver
Connection Conn = DriverManager.getConnection(conn);

// query statement
Statement SQLStatement = Conn.createStatement();

String query = "SELECT * FROM auth_users WHERE email ='email' AND password='password' ";
    
// get result code
int SQLStatus = SQLStatement.executeUpdate(query);
	if(SQLStatus != 0)
	
	{
	
	
	}
	else
	{
	out.println("Error! Please try again.");
	}

// close connection
SQLStatement.close();
Conn.close();

%>

First, I am getting syntax errors on my SQL statement to check "email' and "password" and second, what is the syntax to check if the email and password row is valid?

This is pretty easy in PHP - I have been pulling my hair out trying to find the syntax for JSP.

Any help would be appreciated.

Coach

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October 15th, 2001, 04:35 PM

ACShafer

Not A Jedi Yet

Join Date: Aug 2001

Location: Salt Lake City

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Coach

Hey Coach,

I didn't check all your code, but I can see your problem for the syntax errors on the SQL.

String query = "SELECT * FROM auth_users WHERE email ='email' AND password='password' ";

I'm sure if you read a bit about java Strings, you would figure it out in a snap.

query is being passed to the DB just as you have typed it, if you want the variables email and password to be interpreted you need to do something that looks like this:

String query = "SELECT * FROM auth_users WHERE email ='" + email + "' AND password='" + password + "' ";

I live in SLC, how are the Jazz going to do?

You can send me email if you have any more problems.

Andrew

October 16th, 2001, 01:27 AM

coach

Contributing User

Join Date: Oct 2001

Posts: 94

Time spent in forums: 51 m 10 sec
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duh of course

Thanks Andrew for the syntax tip.
I am learning quickly that the SQL is similar to PHP but not completely compatible.

I do have one more question regarding my code.

As I mentioned - I am trying to authenticate against a MySQL DB and wanted to know the correct syntax for creating a result that would check if the username and password exists - for example

Code:

// query statement
Statement SQLStatement = Conn.createStatement();

String query = "SELECT * FROM auth_users WHERE email ='" + email + "' AND password='" + password + "' "; 
    
// get result code
ResultSet SQLResult = SQLStatement.executeQuery(query);
	if(SQLResult!=null)
	
	{
	out.println("woo hoo.");
	
	}
	else
	{
	out.println("Error! Please try again.");
	}

// close connection
SQLStatement.close();
Conn.close();

I know the result code is incorrect. What is the correct way to find out if the query is true or false?

thanks

Coach

October 16th, 2001, 08:53 AM

ehsiung

Junior Member

Join Date: Jul 2001

Location: Pittsburgh, PA

Posts: 3

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Try this instead:

Code:

if(SQLResult.next()) 

{ 
out.println("woo hoo."); 

} 
else 
{ 
out.println("Error! Please try again."); 
}

Note: executeQuery() always returns a resultset. You need to check if the resultset is empty or not.

October 16th, 2001, 03:50 PM

ACShafer

Not A Jedi Yet

Join Date: Aug 2001

Location: Salt Lake City

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Eric hooked you up.

Don't think of it as trying to learn JSP, learn Java and JSP will be cake.

Your question is really about JDBC.

In some ways, JSP is not as slick as PHP, (but hey, what is?) but Java is robust.

October 18th, 2001, 05:53 PM

sLiPkNoT rUlEz

PHP Coder

Join Date: May 2001

Location: Ontario

Posts: 66

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But then you get into the fun stuff like custom tags, MVC architecture, and templates and question yourself for ever doubting the robustness of JSP

October 26th, 2001, 06:51 PM

Agent0range_

Junior Member

Join Date: Oct 2001

Location: Victoria, BC.

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Quote:

Originally posted by sLiPkNoT rUlEz
But then you get into the fun stuff like custom tags, MVC architecture, and templates and question yourself for ever doubting the robustness of JSP

I second that. Taglibs and the MVC architechtire make webapps so much easier to maintain. Now, if only I could get those damn beans to work for me...

trying to understand JSP

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