Servlet-database communication

Hi,
I wrote an simple code for an application in which i will communicate servlet-bussinesslogic-database.I was success in the forward manner but when i am trying to return the values from the database to the servlet i am not able to return the values. Can anyone help me out to get the way.
Note: i am using a simple application where there are no java beans and other stuff...
please help me out....

I'm sorry to ask this type of question, but it is necessary , because i'm a student studying the yea B.Tech , I have one problem that is i'm trying to get the data from data base through servlets , but i can load the driver but the connection is not forming between the servlet container and jdbc container but i have one idea about that ,
i.e. Up to now i tried on the very popular data bases like (Oracle , SQLServer, MySQL,Microsoft Acess)
But one solution i.e. by ignoring the above mentioned , i want to try the database in the form of xml , for this no need to load the drivers and no need to forn the connections , but we must very well about XML , i don't know how to interact with xml through java application, can any body try it once , if it is success please mention it to my id.

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Servlet/Applet communication, data limit?

I have an applet that uses a servlet as a proxy to load/retrieve images from an Oracle database. I have a problem when trying to retrieve images larger than 9-10kb from the database. When using JDBC from a Java Application I don't have any probelms but through the Applet-Servlet configuration I do.
I use the following code in the Applet:
URL url =new URL("http","myserver",myport,"/servlet/MyServlet");
HttpURLConnection imageServletConn = (HttpURLConnection)url.openConnection();
imageServletConn.setDoInput(true);
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          imageServletConn.setUseCaches(false);
imageServletConn.setDefaultUseCaches (false);
imageServletConn.setRequestMethod("GET");
byte buf[] = new byte[imageServletConn.getContentLength()];
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instr.read(buf);
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thanks in advance!

thanks for your replay,
I tried your suggestion but whatever I do it seems that tha applet only brings the first 5-10k of the image from the servlet. This is the value I get from instr.read() or any other type of read method. The value of bytes is not always the same.
Now I also have something new. For images greater than 100k or so I get this error:
java.io.IOException: Broken pipe
     at java.net.SocketOutputStream.socketWrite(Native Method)
     at java.net.SocketOutputStream.socketWrite(Compiled Code)
     at java.net.SocketOutputStream.write(Compiled Code)
     at java.io.BufferedOutputStream.write(Compiled Code)
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     at java.lang.Thread.run(Compiled Code)
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It seems that this servlet-applet communication is really unstable. If you have anything that may help me it will be greatly appriciated. You can even e-mail me at [email protected]
thanks!

Error #1015: Database Communication Error

Hi,
I am having a WebCTRL application on my infra which is connecting to SQL server 2008 R2.
On application side, we are frequently getting error messages saying that ,
Error #1015: Database Communication Error -- Critical problem occurred (With timings) Reestablished (DBname) database connection. details: Successfully reconnected to the database
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Regards,
Vinodh Selvaraj

Can you check if your database properties set Auto Close to ON , it must be set to OFF
https://msdn.microsoft.com/en-us/library/bb402929.aspx
Best Regards,Uri Dimant SQL Server MVP,
http://sqlblog.com/blogs/uri_dimant/
MS SQL optimization: MS SQL Development and Optimization
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Large scale of database and data cleansing
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Dear Guru's,
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regards,
Guna

Hi,
Guess you are using DB2?
try this
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Hi all,
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The hard part with this solution is
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Hi
I am writing a servlet based upon the multi thread model (default in many cases).In the servlet, I go to database 2 or 3 times per request and get data. I have broken down my main method into 4 methods. so method 1 calls method 2 with some params, method 2 calls method 3 etc.
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thanks

Hi
I am writing a servlet based upon the multi thread
model (default in many cases).In the servlet, I go to
database 2 or 3 times per request and get data. I have
broken down my main method into 4 methods. so method 1
calls method 2 with some params, method 2 calls method
3 etc.
I am using connection pooling. I am passing the
connection object from method 1 to downstream methods.
and release the connection only at the end.
My question is since this servlet can be accessed by
multiple threads, is this a good practice of passing
connection downstream since a servlet might try to
access with a closed connection object. Should I just
get connection objects from the pool and release them
inside each method.
thanksIf the Connection is a local variable for the service, doPost, doGet, etc... there isn't any problem with your aproach.
If it is, then your Connection is shared between all the threads that run concurrently (run througth the servlet).
Concerning your aproach (and the Connection beeing a local variable), there is no problem in passing it to the next method by parameter because it is the same thread running the code.
MSB

Applet / SQL Database communication

I am developing an applet that needs to connect to a SQL Database to keep track of a variety of information. I am running into some errors when I try to connect to the database.
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Thanks.

I am developing an applet that needs to connect to a
SQL Database to keep track of a variety of
information. I am running into some errors when I
try to connect to the database.
Can anyone tell me the best way for an applet to
connect to a SQL database without editing the
client's policy file to give permission?
Any help with this matter would be much appreciated.
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Hi,
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import javax.servlet.http.*;
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1. Don't put business logic in your servlet. A servlet should just be a dispatcher to a business logic layer that has no idea that it's running in a servlet context.
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PreparedStatement ps = con.prepareStatement(sql);
ps.setString(1, cof_name);
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How do i Create charts using JSP/Servlet & Database

I have to create charts which shows the graph of stock exchange.
i have a database that keeps the data for creating charts.
But i did not know how to create charts using jsp-servlet.
Any Example might help me to go forward.
Any help will be really appreciated.
Please Advice me.

JFreeChart - You can generate the charts then convert them to image formats (PNG and JPEG) all using the JFreeChart API
http://www.jfree.org/jfreechart/

ACS and Windows 2000 user database communication port

Could my Windows 2000 SP4 + ACS v3.23 can install any new Windows 2000 service pack ?
I'm affraid to infect ACS Service.
So, I want to install firewall on this server to block malicious traffic.
However, my ACS used external user database Windows 2000 for authentication.
Who can tell me What protocols or port list they are communication?
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Hi cheng
I think you can install any servie pack without problem and the SP4 is the latest one for WIN2000 and you server already has this SP
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http://www.microsoft.com/technet/prodtechnol/windows2000serv/technologies/activedirectory/deploy/confeat/adrepfir.mspx
Best Regards

Servlet Database I/O: How to "lock" a record being updated ?

Say you have a servlet that displays a list of customers in HTML page, and a button on each customer to click to bring up another page (servlet generated) with the customer info to edit. The customer info is in a database file (could be Access or ORACLE). User makes any changes and clicks a button to update the customer record (with a servlet).
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sridharranganathan, does your technique assume that the read operation is locked, so that two users cannot obtain the same value of LockCounter?
I have some questions relevant to the following code:
public class theServlet extends HttpServlet
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     throws ServletException, IOException
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} //end class
public class Helper {
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    private String field2Val= "";
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                      con.setTransactionIsolation(con.TRANSACTION_READ_COMMITTED);
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1. In the servlet, each thread will have its own instance of Helper and of Connection, correct?
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Applet - Servlet - Database - Servlet- Applet

Hi All,
I am using Oracle8i and IE 5.0. I am trying to retrieve the data from a db table and display it.
Sequence is as following:
1. Query passed to the applet.
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3. Applet displaysthe results.
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Thanks a lot.
Manuriti
[email protected]

I've never dealt with the code to handle the applet portion of what you're trying to do, but I can help you with the servlet stuff.
Your servlet should contain code to accomplish the following steps:
1. Load an Oracle JDBC driver into memory.
2. Open a JDBC connection to the Oracle database.
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4. Execute the Statement object, which will return a ResultSet.
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All of these steps are simple. Here's what they might look like in practice:
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Statement stmt = con.createStatement();
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Servlet database problem

Hi iam sending text message from client and storing it in file in server....I want to store text value in database..
I am doing following this to store text in database..............
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{color:#000080}Not sure, but you may need to flush() the OutputStream.fout.write(data);
fout.flush();
fout.close();To post code, use code tags --{color} [code]CODE[/code] {color:#000080}is displayed as CODEdb{color}

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Hi all,
I am a java developer that recently turned its attention to j2me. I have recently wrote an application that sends and receives info from a servlet and uses it in a sort of interrup fashion: the server data constraints the mipd app state.
What I would like to know is, if any of you has written anything like it before, which is the most "elegant" performance-wise way to communicate with a mipd application from a server point-of view.
I mean, there are many ways to approach this and I would like to know more or to cut out the ludicrous one.
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cheers
j.

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The thing is I'm having some problems when I keep readStreams open after a while (inside a while loop waiting for some special code) and I was wondering if this is valid or is indeed a problem with my code.
This is what I meant with tunnel before, not really say raw socket comm between midlets but a tunnel through a server that nevertheless kept each midlet from having to poll the ditto all the time. Apologies for not being too clear about it.
I'm using something like (in pseudo pseudo-code & ommiting all the registration steps etc):
client midlets
conn = openConnection();
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in = conn.getInputStream();
if (!postbox.isEmpty()) {
msg = removeHead(postbox);
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... on a separate thread
while (USER_IS_ON){
msg = in.readStream();
if (msg != null) postbox.add(msg);
close(conn, out, in);
Server
out = request.getOutpuStream();
in = request.getInputStream();
data = in.readStream();
// write this guy's data on the other recipient's queue
queue.add(data, id);
... on a separate thread
while (USER_IS_ON){
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if (data = hasData(id) != null)
out.writeStream(data, id);
close(conn, out, in);
On fear of making this too long, I'll stop here. I can post the source if you wish but it is rather lenghty :-)
Thanks for the help!
cheers
j.

Servlet - j2me communication

hi,
i have written a basic servlet and j2me communication project. servlet gets the command, and increase counter value 1 up. from two different mobile phone emulators, i connect to the servlet. when i send a request to the servlet from one emulator, then counter returns 1. From the other emulator, when i send a request, then counter returns 2. do the two different emulators use the same session of the servlet? what is the servlet's logic? dont the two emulators create their own instance of the servlet?

First of all, when you post code, please, use the "code" tags.
I can't test your code but I start to analyse the method startApp() and there is:
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Servlet-database communication

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