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call java program from a servlet

Posted on 2003-11-14
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Last Modified: 2013-11-24
Hi,
   I am trying to learn how to call a java program from a servlet.
I have a file in unix /tmp/names which contains all the name.


I have one html file which ask for a name as input  and then call the servlet.
The servlet basically has the name variable.  How can I call
another java class to check to see if this name is in the file /tmp/names?


thanks in advance.
0
Comment
Question by:aauser
6 Comments
 
LVL 92

Expert Comment

by:objects
ID: 9752033
Same way you'd call another class from an application. Create an instance and call it's method.
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 9752066
If you've got read perms on the file, just open it from the servlet, iterate it, and look for the name
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 9752085
If you've got read perms on the file, just open it from the servlet, iterate it, and look for the name
0
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Author Comment

by:aauser
ID: 9752213
thanks.
says I have a class call output1:
public class output1 {
     public void output() {
         System.out.println ("The name is ");
}
}



In my servlet, I have line like this:
output1 out = new output1();
out.output();


and when I ran the servlet, I don't see anything on the browser.

0
 
LVL 92

Expert Comment

by:objects
ID: 9752692
stdout does not go to the browser.
You need to write to the output stream of the servlet response for it to be sent to the browser:

PrintWriter out = new PrintWriter(new OutputStreamWriter(response.getOutputStream()));
out.println("The name is");
0
 
LVL 1

Accepted Solution

by:
vishalbhando earned 125 total points
ID: 9753143
You can send out variable from your servlet / jsp to the Class as :
... class output1{
          public void output(){
                output(System.out);
          }
          public void output(PrintStream out){
                output(new PrintWriter(out));
          }
          public void output(PrintWriter out){
                 if(out==null) throw new IllegalArgumentException("out can't be null");
                 out.println(...);
          }

         p s v main(String args[]){
                output1 op=new output1();
                op.output();
         }
}

in servlet call as
output1 op=new output1();
op.output(response.getOutputStream());
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