servlet setting some value need to retrive that value in a normal java file

[Ravi Kiran Va]

Hi ,

I am having a jsp page for submitting values .
All these values are recievied by a servlet .
This servlet in turn calls a normal java file
(This is the flow of our application)


Now the problem is

In that servlet i am setting some value for this i have to pass this value to that java class

For setting value inside servlet ,i have taken help of javaBean class as shown below

public class FlagBean
{
String sldvalue;

public String getSldvalue() {
	return sldvalue;
}

public void setSldvalue(String sldvalue) {
	this.sldvalue = sldvalue;
}
}

Inside servlet :

FlagBean fb = new FlagBean();
fb.setSldvalue("SLDValue")

But when i am trying to retrive this inside my Java Class

String value =fb.getSldvalue()

It is returning me null .

Please help

[Ankit Garg]

So you are actually passing the FlagBean instance that you created in your servlet to the java class?? I don't see any reason how this can happen

[Ravi Kiran Va]

I am also not sure how to do this ?

so please tell me how can the communication from my servlet class to the java class can happen ??

[Andrew Monkhouse]

Perhaps you could show us the bit of your code in the doGet or doPost that is related to the call to your worker bean?

[Vijitha Kumara]

It's not clear what you are trying to do here, Are you trying to call some methods of a bean from the servlet or ...?

[Ravi Kiran Va]

Ankit Garg wrote:So you are actually passing the FlagBean instance that you created in your servlet to the java class?? I don't see any reason how this can happen

thats why i posted .

[Ravi Kiran Va]

Andrew Monkhouse wrote:Perhaps you could show us the bit of your code in the doGet or doPost that is related to the call to your worker bean?

Its nothing but a simple if condition .

// All this inside my servlet 

FlagBean fb = new FlagBean();


if(// some condition )
{
fb.setSldvalue("sld");
}

else
{
fb.setSldvalue("sdo");

}

[Seetharaman Venkatasamy]

well, you are creating the instance(DTO) in servlet and setting a value. where you are getting that? As vijitha said,explain your problem clearly,if you want to solve[get answare] your problem.

[Ravi Kiran Va]

where you are getting that

Oh i am getting that inside my normal java class

FlagBean fb = new FlagBean();  
fb.getSldvalue();

But its returning me null .

Its a 3000 lines of code and relates to Spatial Data and Mapviewer , so could not post all that , so just explained in simple way .

[Seetharaman Venkatasamy]

Ravi Kiran V wrote:

FlagBean fb = new FlagBean();  
fb.getSldvalue();

Hmm.dont create a new instance . use the existing one(in which you set the value) .please google for "instance vs class"

[Ankit Garg]

so please tell me how can the communication from my servlet class to the java class can happen ??

Okay so in your servlet you are doing this

FlagBean fb = new FlagBean();
if(// some condition )
{
fb.setSldvalue("sld");
}
else
{
fb.setSldvalue("sdo");
}

And in your java class you are doing this

FlagBean fb = new FlagBean();  
fb.getSldvalue();

And you are expecting the value sld or sdo to be returned?? You just created a new object in your java class, how will the value magically transfer from your servlet to the normal class?? Can you show us the code where you are calling the normal java file in your servlet. You'll need to pass the FlagBean instance that you create in your servlet to the normal java class for the value to be able to reach the normal java class...

[Ravi Kiran Va]

i dont know that thank you i will try that on monday and let you know that status .

[Ravi Kiran Va]

You'll need to pass the FlagBean instance that you create in your servlet to the normal java class for the value to be able to reach the normal java class...

so Ankit by the above you mean that , don't create new class of FlagBean inside the java class but just call the getter Method it (Am i right to understand this properly ?)


Inside my Java class

FlagBean fb = new FlagBean()

but just fb.getMethod()

[Vijitha Kumara]

Ravi Kiran V wrote:.... don't create new class of FlagBean inside the java class but just call the getter Method it (Am i right to understand this properly ?)
Inside my Java class
FlagBean fb = new FlagBean()
but just fb.getMethod()

You should call the getter of the object you have set the values in, perhaps passing that reference to your java class.

[Ravi Kiran Va]

You should call the getter of the object you have set the values in, perhaps passing that reference to your java class.

Hi i did as per you said but without creating an instance of FlagBean inside my second java class it is not compiling .

For example :

class SecondJavaClass
{
String sldvalue = fb.getMethod() ;
}

Its inot understanding what is meant by fb .
How can i do this ??

[Saifuddin Merchant]

Lot of confusion over this one - so let me try taking up one point at a time,

Ravi Kiran V wrote:Hi ,

I am having a jsp page for submitting values .
--Sam - Right this works

All these values are recievied by a servlet .
--Sam - I think we are good up to this point too

This servlet in turn calls a normal java file
(This is the flow of our application)
--Sam - This is where the problem is - so lets clear up a few things.
There is no such thing as calling a Java File - unless you are using Runtime class to execute the file or something.

What you can do though is create an Object of the plain Java class and call a method or call static method of this plain java class and pass your bean as a parameter to the method!

It will be interesting to know what you are doing currently - I would suggest that you post your entire Servlet class if you are looking for more help!!

[Ravi Kiran Va]

All of you thank you very much .

I have made all the methods and properties to static and its working (without creating an instance of that Bean class)

[Saifuddin Merchant]

Ravi Kiran V wrote:All of you thank you very much .

I have made all the methods and properties to static and its working (without creating an instance of that Bean class)

Might work - but it could be a problem for a web application!! Does it work when you have more that one simultanous request?

[Ravi Kiran Va]

seems interesting sam . ( I did not test for simultaneous requests actually )

But can you please tell me what will be the problem actually .

[Saifuddin Merchant]

Ravi Kiran V wrote:seems interesting sam . ( I did not test for simultaneous requests actually )
But can you please tell me what will be the problem actually .

When you use static properties - you are just working with one copy of the variables. So if one request sets the value to 1 & another sets it to 2 the first value will get over written. Remember the container is going to span different threads to handle each incoming request - so you might end up with cases where you were expecting some value and ended up with another - and these kind of bugs might not even show up when you test the application under low load!

[gaurav kant]

Why don't you do things in this way.
lets take an example :

suppose you have 1 text field named "myText" in jsp. you submitted form to your servlet in which you have called a java class.
Now myText comes in your servlet inside request object. you do 1 thing. pass this complete "request object" inside your java class constructor and assign it to instance variable and then use it in your methods.

some thing like this

Servlet side code:

  MyClass myClass=new MyClass (request);  

MyClass side code:

  
class MyClass{

private HttpServletRequest request=null;

MyClass(HttpServletRequest request){
this.request= request;
}

myClassMethod(){
// Now use this request object according to your need

String myTextString=this.request.getParameter("myText");

}

  

[Ravi Kiran Va]

Thank You sam for your nice explanatation

Gaurav i don't know that we can use HttpServletRequest inside a normal java class (That is our class without extending any Generic Or Http Servlet)
i will certanily this .

Thank you Java Ranch

[gaurav kant]

Yes, you can do. Just import javax.servlet.http.HttpServletRequest and use it. i am sure about it. It will ease your life

[samir singha]

why don't you pass the bean object (fb in your case)created in your servlet to your java class through constructor or method parameter of your java class and get the value from bean object.

[gaurav kant]

samir singha wrote:why don't you pass the bean object (fb in your case)created in your servlet to your java class through constructor or method parameter of your java class and get the value from bean object.

Both are the same things. either direct fetch values from request or do one more step in which first populate bean then use in another class. Do any way you think is good