Can anyone please help me with connect to database

Question

Visualogic 0 Light Poster

16 Years Ago

sorry for annoying, i am quite stupid in it.

<html>
<head>
<title>Welcome to the online Auction...</title></head>
<body>
 
 
<% try
 
{
 
	String strUsername = request.getParameter("username"); 
	String strPassword = request.getParameter("password"); 
	
	Class.forName ("mysql-connector-java-5.0.8-bin"); 
 
 	Connection myConn = DriverManager.getConnection("jdbc:mysql://localhost/user.jsp,admin,admin");
 	
 	Statement myStatement = myConn.createStatement ();
 	
	String strSQL = "SELECT UserName,UserPwd from user where UserName="",UserPwd="";
	
 
	ResultSet myResult = myStatement.executeQuery(strSQL);
	
	String strUser = myResult.getString("UserName");
	String strPass = myResult.getString("Password");
	
	while(myResult.next())
    
    {
	
	if(strUsername.equals(strUser) && strPassword.equals(strPass))
	
                {
                    out.println("Login Successful!");
                }
                else
                {
                    out.println("Login Fail!");
                }
	
	}	
		
	myConn.close();
}
	catch(Exception e){} 
%>
			
</body> 
</html>

i am new to this.

Please help me with this.

my jar file name is mysql-connector-java-5.0.8-bin

Please help me out.

thanks

java-jsp

4 Contributors
23 Replies
195 Views
3 Days Discussion Span
Latest Post 16 Years Ago Latest Post by Visualogic

peter_budo 2,532 Code tags enforcer

16 Years Ago

For once do not use JSP to connect to DB. JSP is for presentation and servlet is for logic. The order should be JSP collect data from user pass it on servlet. Servlet will validate data and if they correct it will attempt to connect to DB. If conection goes well DB operation is processed (insert/update/delete/chceck/retrieve) and servlet retrieve DB respond, after that servlet will either go to next page or return to previous

There is somewhere example how to do it that I posted about 2 years ago and it was recently re-open by somebody

peter_budo 2,532 Code tags enforcer

16 Years Ago

Above example is servlet so it should ba save as java class

peter_budo 2,532 Code tags enforcer

16 Years Ago

Your connection string

conn = DriverManager.getConnection("jdbc:mysql://localhost/processing.jsp"
			+ "visualogic?UserName=admin&UserPwd=admin");

VS

my connection string

conn = DriverManager.getConnection("jdbc:mysql://localhost/" 						+ "database_name?user=my_username&password=my_password");

Can you explain me what is the purpose of processing.jsp in your code?

peter_budo 2,532 Code tags enforcer

16 Years Ago

The "processing.jsp" is not supposed to be there. Connection string uses the database URL jdbc:mysql://localhost/ , database name database_name , database user name UserName=admin and password UserPwd=admin to establish connection with database.

Please read through these Java tutorials, just be aware they using Derby database instead of MySQL

peter_budo 2,532 Code tags enforcer

16 Years Ago

Well then tell us what you do not understand

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Visualogic 0 Light Poster · Answer 1 · 2008-05-27T08:28:55+00:00

can you show me some example for that...

i am too confuse with it

thanks

Visualogic 0 Light Poster · Answer 2 · 2008-05-27T09:40:03+00:00

i saw ur code for the connection

public class SomeClassName extends HttpServlet
{
Connection conn;
Statement stmt;
	
public void init() throws ServletException
{
	try
	{
		Class.forName("com.mysql.jdbc.Driver").newInstance();
	}
	catch (Exception ex)
	{
		System.out.println("Exception is : " + ex.toString() );
	}
}
	
public void doPost( HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException
{
	try
	{
		conn = DriverManager.getConnection("jdbc:mysql://localhost/processing.jsp"
			+ "visualogic?UserName=admin&UserPwd=admin");
		stmt = conn.createStatement();
	}
	catch(SQLException ex)
	{
		System.out.println("SQLException : " + ex.getMessage() );
	}public class SomeClassName extends HttpServlet
{
Connection conn;
Statement stmt;
	
public void init() throws ServletException
{
	try
	{
		Class.forName("com.mysql.jdbc.Driver").newInstance();
	}
	catch (Exception ex)
	{
		System.out.println("Exception is : " + ex.toString() );
	}
}
	
public void doPost( HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException
{
	try
	{
		conn = DriverManager.getConnection("jdbc:mysql://localhost/processing.jsp" 
			+ "visualogic?UserName=admin&UserPwd=admin");
		stmt = conn.createStatement();
	}
	catch(SQLException ex)
	{
		System.out.println("SQLException : " + ex.getMessage() );
	}

am i doing right?
what file shall i save to?
.jsp or.....

Visualogic 0 Light Poster · Answer 3 · 2008-05-28T11:58:42+00:00

i get error for it
here is the error

org.apache.jasper.JasperException: /processing.jsp(1,17) quote symbol expected
org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:40)
org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:407)
org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:88)
org.apache.jasper.compiler.Parser.parseAttribute(Parser.java:200)
org.apache.jasper.compiler.Parser.parseAttributes(Parser.java:150)
org.apache.jasper.compiler.Parser.parseAttributes(Parser.java:162)
org.apache.jasper.compiler.ParserController.getPageEncodingForJspSyntax(ParserController.java:451)
org.apache.jasper.compiler.ParserController.determineSyntaxAndEncoding(ParserController.java:392)
org.apache.jasper.compiler.ParserController.doParse(ParserController.java:173)
org.apache.jasper.compiler.ParserController.parse(ParserController.java:103)
org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:153)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:314)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:294)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:281)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:566)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:317)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:337)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)

Visualogic 0 Light Poster · Answer 4 · 2008-05-28T13:13:16+00:00

it is trying to get to authencate the username and password.

Visualogic 0 Light Poster · Answer 5 · 2008-05-28T13:33:50+00:00

hmm, not really understand it

sorry for annoying

Visualogic 0 Light Poster · Answer 6 · 2008-05-28T14:49:22+00:00

conn = DriverManager.getConnection("jdbc:mysql://localhost:8080/"
			+ "visualogic UserName=admin&UserPwd=admin");

conn = DriverManager.getConnection("jdbc:mysql://localhost/" 						+ "database_name?user=my_username&password=my_password");		conn = DriverManager.getConnection("jdbc:mysql://localhost/" 						+ "database_name?user=my_username&password=my_password");

Behind the localhost/ what shall i put?
and the database_name=my database name?
my_username&password=my database username and password?

peter_budo 2,532 Code tags enforcer Team Colleague Featured Poster · Answer 7 · 2008-05-28T15:10:33+00:00

This is correct

conn = DriverManager.getConnection("jdbc:mysql://localhost/"+ "visualogic UserName=admin&UserPwd=admin");

port number is only used when you connecting to IP address of server, however as DB is on local machine the keyword "localhost" is used. Secondly 8080 is port for Tomcat not for database

Visualogic 0 Light Poster · Answer 8 · 2008-05-28T15:21:17+00:00

Visualogic 0 Light Poster

16 Years Ago

oh, let me try it again

thanks

Visualogic 0 Light Poster · Answer 9 · 2008-05-28T15:26:11+00:00

another question, after i wrote this code

public class SomeClassName extends HttpServlet
{
Connection conn;
Statement stmt;
	
public void init() throws ServletException
{
	try
	{
		Class.forName("com.mysql.jdbc.Driver").newInstance();
	}
	catch (Exception ex)
	{
		System.out.println("Exception is : " + ex.toString() );
	}
}
	
public void doPost( HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException
{
	try
	{
		conn = DriverManager.getConnection("jdbc:mysql://localhost:/"
			+ "visualogic UserName=admin&UserPwd=admin");
		stmt = conn.createStatement();
	}
	catch(SQLException ex)
	{
		System.out.println("SQLException : " + ex.getMessage() );
	}public class SomeClassName extends HttpServlet
{

what shall i do?

or can i use this code

<%@page import=java.util.*"%>
<jsp:useBean id="idhandler" class="authenticate.login"scope="request">
<jsp:setProperty name="idhandler" property="*"/>
</jsp:useBean>
<%
	if(idhandler.authenticate()){
%>
<jsp:forward page="details.jsp"/>
<% }
else{ %>
<jsp:forward page="error.jsp"/>
<% } %>
package authenticate;
import java.sql.*;
public class Login{
private String username="";
private String password="";
public Login(){
}
public void setUsername(String username){
this.username=username;
}

public void setPassword(String password){
this.password=password;
}

piblic String getUsername()
{
	return username;
}

public String getPassword()
{
	return password;
}

public boolean authenticate(){
String query="select * from user;";
String DbUserName;
String DbUserPwd;
try{
	Class.forName("com.mysql.jdbc.Driver");
	Connection conn=DriverManager.getConnection("jdbc:mysql://localhost:/"+ "visualogic UserName=admin&UserPwd=admin");
	Statement st=con.createStatement();
	ResultSet rs=st.executeQuery(query);

while(rs.next()){
DbUsername=rs.getString("username");
System.out.println("username:"+DbUserName);
System.out.println("Entered user name:"+username);
DbUserPwd=rs.getString("Password");
System.out.println("Password="+DbUserPwd);
System.out.println("Entered password:"+password);
if(username.equals(DbUserName) && password.equals(DbUserPwd))
{
	return true;
}
}
}catch(Exception e){
e.printStackTrace();
}
return false;
}
}

peter_budo 2,532 Code tags enforcer Team Colleague Featured Poster · Answer 10 · 2008-05-28T22:52:46+00:00

Use the first code, the second one is a bad practice.

To your question what should you do with first code. This code is general bridge to setup connection, before this you should collect some data from the form and now you would try to put them in DB or somebody just pressed one of the buttons that has functionality based on some sort of DB communication (get total sum for monthly income in shop for example). So JSP provide input and pass it on the servlet from which you have the opening part. Servlet does form validation if neccesary, proces or retrieve data from DB and provide appropriate re-direction to next JSP (usualy).

Read the tutorials which I gave you link and apply that to what you already got. Also you may want to look at this too

jwenting 1,889 duckman Team Colleague · Answer 11 · 2008-05-29T00:54:43+00:00

kid's still insisting on doing database access from JSP.
Maybe if it would stop trying that it would get somewhere...

Visualogic 0 Light Poster · Answer 12 · 2008-05-29T06:28:39+00:00

Jwenting, thanks for the advise.
I get the second part from another site. :)

lets me try it again

thanks alot

Visualogic 0 Light Poster · Answer 13 · 2008-05-29T09:04:52+00:00

let see this
user login page

<html>
<head>
<title>User Login Page</title>
<body>
<h2><center>Visualogic </center></h2><br>
<b>
<center><form name="form" method="post" action="????????">
	Username: <input type="text"name="username" value=""><br><br>
	
	Password: <input type="password" name="password" value=""><br><p></p>
	
	<input type="submit" name="Submit" value="Login">
	
	<input type="reset" name="Reset" value="Reset"><br><p></p></center>
</form> 
</body>
</html>

connector.java

import java.sql.*;
public class SomeClassName extends HttpServlet
{
Connection conn;
Statement stmt;
	
public void init() throws ServletException
{
	try
	{
		Class.forName("com.mysql.jdbc.Driver").newInstance();
	}
	catch (Exception ex)
	{
		System.out.println("Exception is : " + ex.toString() );
	}
}
	
public void doPost( HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException
{
	try
	{
		conn = DriverManager.getConnection("jdbc:mysql://localhost:/"
			+ "visualogic UserName=admin&UserPwd=admin");
		stmt = conn.createStatement();
	}
	catch(SQLException ex)
	{
		System.out.println("SQLException : " + ex.getMessage() );
	}public class SomeClassName extends HttpServlet
{

for the form action, do i set it as connection.java so that when the user login , the data will validate it from the database?

peter_budo 2,532 Code tags enforcer Team Colleague Featured Poster · Answer 14 · 2008-05-29T16:04:57+00:00

Action requere direction (file name) where to go next so it can look like this

action="http://localhost:8080/ProjectDirectoryName/servlet/NameOfServletWithoutExtension"

, there is advanced way how to work with action element but for that you would have to know something about servlet mapping so leave it for now.
So now on submit button click you go to your servlet, that will initialize connection string, you should retrive values from JSP, validate them and then open connection to DB and do what ever you need. After that do not forget to close conection to DB and redirect process flow to appropriate page.
Note: Validation is part of your job, you have to design it.

Visualogic 0 Light Poster · Answer 15 · 2008-05-29T18:10:40+00:00

Visualogic 0 Light Poster

16 Years Ago

ok
thanks

peter_budo 2,532 Code tags enforcer Team Colleague Featured Poster · Answer 16 · 2008-05-29T18:29:41+00:00

I have few books that I use as references for Java web development Java How to Program (6th edition as it is still using MySQL as main database, 7th edition went for Derby DB), Beginning JSP, JSF & Tomcat Web Development: From Novice to Professional and Tomcat: The Definitive Guide (2nd edition). Many of O'Reilly books are also available for free from their website

ashish1234 -2 Newbie Poster · Answer 17 · 2008-05-30T04:27:16+00:00

What is exactly ur problem..which one r u using java/jsp?

Visualogic 0 Light Poster · Answer 18 · 2008-05-30T12:24:36+00:00

jsp
peter_budo , thanks for the advise

if i have another question, i will post it in here