Threading concepts used in servlet programming
Hello Everybody,
I have rquirement like .. three servlets are there in my application..by using threading concept only one servlet should get chance ..reaming two are in lock mode till first servlet finishes.
Any body having idea on this requirement plz help me..If any body having examples related to this ..plz post here.
Thanks In advance.
regards,
Anil.
I have rquirement like .. three servlets are there in my application..by using threading concept only one servlet should get chance ..reaming two are in lock mode till first servlet finishes.That is an unreasonable requirement, and will end up breaking your web-app the first time it gets accessed by more than one user (ie, you won't see the problem during development, probably not during QA, then you'll get a call as soon as it hits production).
Why do you think you need this requirement?
Are the servlets supposed to be executed in a particular order? That can be handled via coding.
Do they make use of a shared resource? That can be handled by controlling access to the resource. I will note that most shared resources do not need long-term atomicity, and databases already provide it.
Similar Messages
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Please help me to use javamail to send mail in servlet program
hi
i want to send simple mail from user [email protected] to user [email protected] using servlet program
i can't compile the javamail demo program servlet "JavaMailServlet.java".
i have this exception
Note: SendMailServlet.java uses or overrides a deprecated API.
Note: Recompile with -deprecation for details.
i don't no how to do
please help me if you have code
thank'sGiven that you're having problems with your [url http://forum.java.sun.com/thread.jsp?forum=43&thread=536278&tstart=0&trange=30]demo mail code as well as your demo servlet code, perhaps you would be better served by learning about JavaMail, servlets, and perhaps Java in general (for example - the meaning of deprecated). Then you may be able to build your own servlet for handling mail or at least will be able to revise the demo code found elsewhere.
Of course, if the purpose is really not to learn how to use Java, JavaMail, servlets, etc. but to simply create something that works then you could always hire someone to write the program for you.
This is not intended to be rude or anything - just an observation and some food for thought.
∞ brewman ∞ -
Unable to run Servlet program using J2EE SDK
Hello,
i am a newbie to all this j2ee stuff and servlets even.so the problem that i have maybe a very common one and i hope that most of you may have a fix to it...
i use J2EE SDK to compile and run Servlet programs.I have a Servlet program with the class name defined as
public class MyServlet extends HttpServlet ....
the file is stored as MyServlet.java
i set the CLASSPATH variable so that the required classes for the compilation of the program can be located.
the program compiles without any glitches.
However when i run the program by saying
java MyServlet
( i dont think its any different to run servlet code is it?)
i get the message
java.lang.NoClassDefFoundException:MyServlet
Can someone suggest a remedy?
thank you
-NDKFirst, I don't understand what you are trying to do. Running a servlet ?
Servlets are ran by an application server ! (Apache Tomcat ....).
Second, is your class in any package ? -
How long is a thread in use when modem user hits servlet? (repost from misc group)
I'm developing an application that will go out to many users on the
internet. Most will be using modems and so my data center will have to
trickle packets to them because of their low modem bandwidth. Each
transaction is short lived, under 100ms, but I'm concerned that the
execution thread in weblogic will be tied up for several seconds while the
data served is tricked down over the modem.
- Is the weblogic execution thread returned when a servlet call returns, or
only when the stream back through the web server has been emptyied?
- Will in fact calls to write to the output stream (or flushes at least) of
the servlet block until the TCPIP stack returns with data sent OK - ie block
until all the data is sent over the modem?
- If I use buffered output streams with large enough buffers to hold all
served data, and don't flush them before returning with the servlet call,
what does weblogic do? Will weblogic hold the execution thread until it can
empty the buffer, hence be delayed by the modem?
- Does putting netscape enterprise server between weblogic and the client
fix this - will enterprise server buffer the data?
- Does setting keep alive in weblogic or enterprise server have any effect
on this problem?
Thanks.
Mark Johnson
Markj
Mark Johnson.
Encirq Corporation, San Francisco CA, (415)284-9800x116
http://www.encirq.com/ [email protected]
The information contained in this message is CONFIDENTIAL. It is intended
only to be read by the individual or entity named above or their designee.
If the reader of this message is not the intended recipient, you are on
notice that any distribution of this message, in any form, is strictly
prohibited. If you have received this message in error, please immediately
notify the sender and/or Encirq Corporation by telephone at 415-284-9800 and
delete or destroy any copy of this message.Thanks for your reply!!!
jwenting wrote:
no, your code is NOT correct.
It doesn't "upload" anything, as I stated before.It is working perfectly fine if the destination folder is connected to the server machine (which is not the case now).
>
Look into multipart MIME requests, Jakarta Commons File Upload, and things like that to actually upload files to a server instead of insisting on reading them directly from the client's filesystem in your servlet and wondering why that doesn't work if the servlet container is running on a different computer from the client.I AM using Jakarta Commons File Upload. The problem is when I try to access the destination folder(which is in client machine), it can't find as it is searching for the corresponding folder in the server.
>
Unless and until you do that, you're wasting our time and your own.I thought someone could help me i giving me some pointers which I missed. Thanks again!!
Edited by: AnishThomas on Mar 14, 2008 8:13 AM -
How to configure a servlet program using Eclipse?
Hi,
Am just learning Java and J2ee..Am not efficient..Don't laugh @ my question..
I installed jdk 1.6, Apache tomcat 5.0 and eclipse 3.2.1 and also installed wtp plugin to work with j2ee perspective of eclipse..I did this in my PC..could U plz tell me what I need to install in addition?
How come I write my Servlet program using Eclipse...
Thanq
Vani.This is the Sun Java System Messaging Server forum. Though this application software bears Java in it's name it has nothing to do with the programming language Java.
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Concept of variable-free programming.
Can anyone clearly explain the "concept of variable-free programming",
in Object Oriented Programming with a sample code.
Thank you very muchGoogle says:
["variable-free programming" found in Google search|http://books.google.com/books?id=Sz4fsW1CMrIC&pg=PA390&lpg=PA390&dq=concept+of+%22variable-free+programming%22&source=bl&ots=k2E1ea0ENf&sig=zl2lsjo5V-bdXuJvaGEhSjStiZw&hl=en&ei=3avVSfT3FKaMtgOxr72sCg&sa=X&oi=book_result&ct=result&resnum=5#PPA391,M1]
Bottom of page 390 to top of page 391. It's a C# book, but the accessor (getter and setter) concept is certainly used in Java. The whole paragraph could be applied to Java. [Google's book search doesn't let you cut-and-paste the full paragraph, and I don't feel like typing it all myself. ;) ]
Google finds the term elsewhere, too.
That said, I've certainly never heard the term (and, obviously, the other people in the thread haven't heard it, either). -
I have a fully paid subscription to CC and use of installed programs but I can no longer sign in to CC. It repeatedly says "You've been signed out". I have the need to install another program but I can't sign in.
Sign Out When Sign In http://forums.adobe.com/thread/1450581?tstart=0 may help
-and http://helpx.adobe.com/creative-cloud/kb/unable-login-creative-cloud-248.html -
Populating the Addressee field using Customer Interface program
Hello All,
Can any body tell me how to populate the "Addressee" column in the HZ_Party_Sites table using Customer Interface Program. Which field should be populated in RA_Customers_Interface_All table inorder to populate the "Addressee" field.
Thank you,
VijayYou can post this thread in this
Customers as well.
Thanks
GM -
How to use another java program to stop this running prpgram???
Dear Sir:
I have following code and I run it success,
import java.util.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.*;
public class CertainAndRepeatTime{
public static void main(String[] args) throws IOException{
int delay = 1;
Timer timer = new Timer();
ActionListener actionListener = new ActionListener() {
public void actionPerformed(ActionEvent actionEvent) {
System.out.println("Hello World Timer");
System.out.println("What do you want (Certain time or Repeat time)?");
System.out.print("Please enter \'C\' or \'R\' for that: ");
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
String ans = in.readLine();
System.out.print("Please enter ans=" + ans + " IsTrue= " + (ans.equals("R") || ans.equals("r")) +"\n");
if (ans.equals("C") || ans.equals("c")){
//System.out.println("This line is printed only once start...");
timer.schedule(new TimerTask(){
public void run(){
System.out.println("This line is printed only once.");
},delay,1);
else if(ans.equals("r") || ans.equals("R")){
timer.scheduleAtFixedRate(new TimerTask(){
public void run(){
System.out.println("This line is printed repeatedly.");
},delay, 1000);
while(true){
//System.out.println("Charles print This line is printed repeatedly.");
} //This will make your main thread hang.
else{
System.out.println("Invalid Entry.");
System.exit(0);
System.exit(0);
}But I hope to use another java program to stop it when it is running instead of pressing CRTL + C to stop it.
How to do it??
Any example??
Thanks a lot!!Sorry, I think i did not express cearly. It is my fault.
I re-write my requirements again:
I have
Class AAA1.java,
Class AAA2.java,
Class AAA3.java,
Class AAA20.java...
etc
they all look like the program I posted first time,, once executed, they will run for ever, and they will be stopped until I press CRTL + C;
Now I hope to use another java class StopProgram.java to stop them 1 by 1 or at once instead of pressing CRTL + C;
In this case, how to code this StopProgram.java ??
Thanks -
hi all,
i write simple hello servlet program in eclipse...
but compiler tells " javax.servle.* " cannot be resolved...
plz clarify how to run servlet program in eclipse as a tomcat webserver....
import java.io.*;
import javax.servlet.*;
public class helloservlet extends GenericServlet{
public void service(ServletRequest request, ServletResponse response) throws ServletException, IOException
response.setContextType("text/html");
PrintWriter pw= response.getWriter();
pw.println("hello servlet");
pw.close();
}regards
machepallihi,
if you are using tomcat 5.5 server use jdk1.5 and if you use tomcat 5.0 use jdk1.4 then compatability adjust.And jar files to library go to tomcat-home ->common->lib->Servelet-api.jar file to your java program library.....
And better to use myeclipse1.4 instead of eclipse ... bcoz sometimes it requires plugins to avoid that use myelipse1.4 ...... -
Weblogic error while deplying a simple servlet program
Hi This is a very simple servlet program.
I am trying to deploy it on the weblogic server but i get this error as follow
Unable to access the selected application.
*javax.enterprise.deploy.spi.exceptions.InvalidModuleException: [J2EE Deployment SPI:260105]Failed to create*
DDBeanRoot for application, 'E:\AqanTech\WebApp1\myApp.war'.
I have checked everything, right from my code to my web.xml file. I have used a build.bat file to build my war file.
PLEASE HELP ME TO SOLVE THIS HUGE PROBLEM OF MINE ?
Thanks,
ShoebHi,
The J2EE Error code siply suggest that there is something wrong in your Deployment Descriptors...
Can u please post the XML files available inside your "WEB-INF" directory?
Thanks
Jay SenSharma
http://jaysensharma.wordpress.com (WebLogic Wonders Are Here) -
Inputting an excel file to the java servlet program
Hi,
How can I input an excel file into the java servlet program? I am using POI HSSF programming to read the content of that excel file.I have created a form that will accept the path from the user and in the servlet program, I have called a post method to retrieve the path of the file. I am getting the path of the file as a string.Then I have to access the file to read the data. But it is not working. What should I do?.Please help me.
I have created an html file to create a form that will ask the path of the file to be loaded into the servlet program.Please give me a solution,thanks in advance. The servlet program that receives the file is shown below. It just only take the name of the file and prints if that is ok.
<html>
<body bgcolor="green">
<center>
<form method="post" action="http://localhost:8080/examples/servlet/Ron1">
<table>
<tr>
<td><B>ENTER THE PATH OF THE FILE</td>
<td><input type=file name="path"></td>
</tr>
</table>
<input type=submit value= "submit" >
</form>
</body>
</html>
import java.io.*;
import javax.servlet.*;
import java.lang.*;
import javax.servlet.http.*;
import java.sql.*;
import java.text.*;
import java.util.*;
import com.oreilly.servlet.MultipartRequest;
import org.apache.poi.hssf.usermodel.*;
public class Ron1 extends HttpServlet
public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException
response.setContentType("text/html");
PrintWriter out = response.getWriter();
String u = request.getParameter("FileToUpload");
out.println("The Path is "+u);
System.out.println("The path is "+u);
MultipartRequest multi = new MultipartRequest(request,u,10 * 1024 * 1024);
System.out.println("path is "+u);
Enumeration files = multi.getFileNames();
File fUploadedFile = null;
String sFileName = "";
out.println("path is "+u);
while(files.hasMoreElements())
String name = (String)files.nextElement();
out.println("file is "+name);
sFileName = multi.getFilesystemName(name);
String type = multi.getContentType(name);
fUploadedFile = multi.getFile(name);
FileInputStream fis= new FileInputStream(fUploadedFile);
HSSFWorkbook wb=new HSSFWorkbook(fis);
System.out.println("The path is "+u);
out.println("File has identified successfully\n");
out.close();
}Hi,
Can you try to use classes from java.net package (URL, URLConnection) to pass the contents of excel file to servlet?
HTH
Vishal -
I wrote an install program (.exe) that is downloaded from a website. When run, it 1) leads a customer to browse to a directory, and 2) copies files (.exe, .dll, etc.) from a website to that directory. When I run, the installed program works.
What are the steps to make it seamless for a customer to use the install program and then use the installed program?
bhs67This site https://msdn.microsoft.com/en-us/library/vstudio/2kt85ked%28v=vs.110%29.aspx provides a basic description of the Visual Studio Windows Installer.
Near the bottom of the page is "You can unlock all the features of InstallShield by paying to upgrade to the full version of InstallShield." Where do I find info that describes the differences between the "free" and the "full"
versions?
bhs67
Hello,
The default feature does support the task for your requirement, so there is no need to pay for the other features unless you want to use some feature which is not free.
In addition, as this thread
InstallShield LE not available with VS 2012 RTM? shared, even through there is a link to InstallShield LE in the New Project dialog under Deployment solutions, but it belongs to third-party that I would recommend you consider posting this issue
at the following forum to get supports about InstallShield.
http://community.flexerasoftware.com/forumdisplay.php?133-InstallShield
Regards.
Carl
We are trying to better understand customer views on social support experience, so your participation in this interview project would be greatly appreciated if you have time. Thanks for helping make community forums a great place.
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HERE to participate the survey. -
Trying to understand the basic concept of object oriented programming.
I am trying to understand the basic concept of object oriented programming.
Object - a region of storage that define is defined by both state/behavior.
( An object is the actual thing that behavior affects.)
State - Represented by a set of variables and the values they contain.
(Is the location or movement or action that is the goal that the behavior is trying to accomplish.)
Variables- (What does this mean?)
Value - (What does this mean?)
Behavior - Represented by a set of methods and the logic they implement.
( A set of methods that is built up to tell's the how object to change it's state. )
Methods - A procedure that is executed when an object receives a message.
( A very basic comand.For example the method tells the object to move up, another method tells the method to go left. Thus making the object move up/left that combination is the behavior.)
Class - A template from which the objects are created.
( I am very confused on what classes are.)
- The definitions of the words I obtained from the "Osborne Teach Yourself Java". The () statements are how I interperate the Mechanisms (I do not know if Thats what you call them.) interact with each other. I understand my interpretation may be horribly wrong. I will incredibly appreciate all the support I may get from you.
Thank youObject oriented programming is a replacement for the older idea of procedural programming (you can research procedural programming in google). As I understand it, in procedural programming, you have a step by step set of function calls to accomplish some task. Each function receives a data structure, manipulates it, and passes it to the next function. The problem with this is that each function preforms some action for the overall task and can't easily be reused by some other task. Its also harder to read the flow of what is happening with raw data structures flying all over the place.
In object oriented programming, an object calls a function of another object and receives back, not a data structure, but another object. Objects contain a data structure that can only be accessed by its functions. An object is not so much a sub component of a bigger task, as it is a service that any other task can use for any purpose. Also, when you pass an object to the caller, the caller can ask questions about the data structure via its functions. The developer doesnt have to know what the previous function did to the data by reading up on any documentation, or having to reverse engineer the code.
I suggest the best way of learning this is to code something like a library object.
A library object contains a collection of book objects
A book object contains a collection of chapter objects
A chapter object contains a collection of paragraph objects
A paragraph object contains a collection of sentence objects
A sentence object contains a collection of word objects.
Add functions to each object to provide a service
Example: A library object should have a:
public void addBook(Book book)
public Book getBook(String title)
public boolean isBookInLibrary(String title)
The key is to add functions to provide a service to anyone who uses your object(s)
For example, what functions (service) should a paragraph object provide?
It shouldn't provide a function that tells how many words there are in a sentence. That function belongs to a sentence object.
Lets say you want to add a new chapter to a book. The task is easy to read
if you write your objects well:
Sentence sentence1=new Sentence("It was a dark and stormy night");
Sentence sentence2=new Sentence("Suddenly, a shot ran out");
Paragraph paragraph=new Paragraph();
paragraph.addSentence(sentence1);
paragraph.addSentence(sentence2);
Paragraphs paragraphs=new Paragraphs();
paragraphs.addParagraph(paragraph);
Library library= new Library();
library.getBook("My Novel").addChapter("Chapter 1",paragraphs).
Now, lets say you want to have a word count for the entire book.
The book should ask each chapter how many words it contains.
Each chapter should ask its paragraphs, each paragraph should ask
its sentences. The total of words should ripple up and be tallied at each
stage until it reaches the book. The book can then report the total.
Only the sentence object actually counts words. The other objects just tallies the counts.
Now, where would you assign a librarian? What object(s) and functions would you provide?
If written well, the project is easily extensible. -
How can i use this java program to access from a jsp page?
import java.io.*;
import java.util.*;
public class FileProcessing
//create a vector container for the input variables
Vector variables = new Vector();
//create a vector container for the constants
Vector constants = new Vector();
/*create a string expression container for the equation
as read from the file */
String expression = " ";
//create double result container for the final result
double result = 0;
public boolean processFile(String filename,String delim)
//index for values vector
int num_values = 0;
//index for constants vector
int num_constants = 0;
//current line being read from the external file.
String curline = " ";
//start reading from the external file
try
FileReader fr = new FileReader(filename);
BufferedReader br = new BufferedReader(fr);
while(true)
curline = br.readLine();
if(curline == null)
break;
//determine the type of current interaction
boolean variable = curline.startsWith("input");
boolean constant = curline.startsWith("constant");
boolean equation = curline.startsWith("equation");
boolean output = curline.startsWith("result");
//on input variables
if(variable)
StringTokenizer st = new StringTokenizer(curline,delim);
int num = st.countTokens();
int count=0;
while(st.hasMoreTokens())
String temp = st.nextToken();
if(count==1)
byte b[]= new byte[100];
System.out.println(temp);
System.in.read(b);
String inputval = (new String(b)).trim();
variables.add(num_values,inputval);
num_values++;
count++;
// on constant values
if(constant)
StringTokenizer st = new StringTokenizer(curline,delim);
int num = st.countTokens();
int count = 0;
while(st.hasMoreTokens())
String temp = st.nextToken();
if(count==1)
byte b[]= new byte[100];
System.out.println(temp);
System.in.read(b);
String cons = (new String(b)).trim();
constants.add(num_constants,cons);
num_constants++;
count++;
// on equation
if(equation)
StringTokenizer st = new StringTokenizer(curline,delim);
int num = st.countTokens();
int count = 0;
while(st.hasMoreTokens())
String temp = st.nextToken();
if(count==2)
this.expression = temp;
count++;
// now we are ready to evaluate the expression
if(output)
org.nfunk.jep.JEP myparser= new org.nfunk.jep.JEP();
myparser.setAllowAssignment(true);
for(int i=1;i<variables.size()+1;i++)
String name = "arg"+Integer.toString(i);
myparser.addVariable(name,new Double(variables.get(i-1)
.toString()).doubleValue());
for(int i=1;i<constants.size()+1;i++)
String name = "arg" +Integer.
toString(i+variables.size());
myparser.addConstant(name,new Double(constants.get(i-1).toString()));
//output is obtained as follows
myparser.parseExpression(expression);
result = myparser.getValue();
System.out.println("Assay value: "+result);
catch(Exception e)
System.out.println(e.toString());
return true;
public static void main(String[] args)
FileProcessing fp = new FileProcessing();
fp.processFile("input.eqn",":");
}here i need to generate the strings like 'enter value1' and respective text boxes dynamically . i should use this java program as business logic and a jsp page for view.
following given is my text file input.eqn
input:enter value1:arg1
input:enter value2:arg2
input:enter value3:arg3
constant:enter constant1:arg4
constant:enter constant2:arg5
equation:enter equation:(arg1+arg2)*(arg3+arg4)*arg5
result:Why do you double post ? http://forum.java.sun.com/thread.jspa?threadID=646988&tstart=0
Why dint that answer satisfy you ? And why dint you say so in that thread rather than posting the same question again ?
ram.
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