when filewriter(file, true) second attribute is true, the output is written twice.?

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jiepie2@gmail.com - 10 Sep 2007 20:56 GMT

why does my out put file "log.txt" has the output written twice?

here is my code:

package productsupport;

import java.io.FileWriter;
import java.io.IOException;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;

import java.util.GregorianCalendar;
public class setAtt extends HttpServlet {
    private String driver, dburl;

    public void doGet(HttpServletRequest request,
         HttpServletResponse response)
throws IOException, ServletException
{
        BufferedWriter log = new BufferedWriter (new FileWriter("log.txt",
true));
        response.setContentType("text/html");
response.setHeader("pragma", "no-cache");
String ip = request.getParameter("ip");
String port = request.getParameter("port");
String sid = request.getParameter("sid");
String user = request.getParameter("user");
String password = request.getParameter("password");
String schema = request.getParameter("schema");
String parkId = request.getParameter("parkId");
String attId= request.getParameter("attId");
String attValue= request.getParameter("attValue");
String query = "";
String siteId="";
Calendar now = new GregorianCalendar();

for (int i=0; i< request.getParameterValues("siteId").length ;
i++ ){
     if (i != (request.getParameterValues("siteId").length -1) ){
         siteId = siteId + request.getParameterValues("siteId")[i] +
",";
     }else {
         siteId = siteId + request.getParameterValues("siteId")[i];
     }

}

driver = "oracle.jdbc.driver.OracleDriver";
dburl = "jdbc:oracle:thin:" + user + "/" + password +
                             "@" + ip + ":" + port + ":" + sid;
PrintWriter out = response.getWriter( );
out.println("<HTML>");
out.println("<HEAD>");

/* java scripts*/
out.println("<script type=\"text/javascript\">");
/**
* function sumbitForm
*/
out.println("function submitForm(actionPage) {");

out.println("document.getElementById('setAttForm').action=actionPage;");

out.println("document.getElementById('setAttForm').submit();");
out.println("return 0; ");
out.println("}");
out.println("</script>");

out.println("<TITLE>");
out.println("Please Select the Park you want to update.");
out.println("</TITLE>");
out.println("</HEAD>");
out.println("<BODY>");
out.println("<H3>");
out.println("Please select the park you want to update.");
out.println("</H3>");
out.println("Site id: " + siteId);
/* connection details*/
out.println("<form id='setAttForm'>");
out.println("<br> Host or IP: <input type=text id=ip size=15
name=ip value="+ip+" / >" );
out.println("Port: <input type=text id=port name=port size=5
value="+ port +" />");
out.println( "sid: <input type=text id=sid name=sid size=3
value=" + sid +" />");
out.println( "User: <input type=text id=user name=user
value="+user+" />");
out.println( "Password: <input type=text id=password
name=password value=" + password+" />");
out.println( "Schema: <input type=text id=schema
name=schema value=" + schema+" /><br>");
out.println( "Park id: <input type=text id=parkId
name=parkId value=" + parkId+" /><br>");
out.println("<br> Attribute ID: " + attId);
out.println("<br> Attribute Value: " + attValue);

/*check which attribute to update,
* and only update attribute when attribute value was
provided
*/

     log.newLine();
log.append("log file opened");
if (attId.equals("218")&& !attValue.equals("")){

     for (int i=0; i< request.getParameterValues("siteId").length;
i++ ){
         out.println("<br><br> Update site id: " +
request.getParameterValues("siteId")[i]);
         query = "update "+schema+".p_prd_attr set
attr_value='"+attValue+"' where attr_id=" +
                 attId +" and prd_id=" +
request.getParameterValues("siteId")[i]+ " ";
         out.println("<br>query: "+    query);
         try{

             out.println("<br>start logging ");
             log.newLine();
             log.write(now.get(Calendar.HOUR) +":"+
now.get(Calendar.MINUTE)+":"+
                     now.get(Calendar.SECOND)+": "+ query);
             out.println("<br>end logging ");

             dbAccess dbase = new dbAccess (driver, dburl);
             //ResultSet rs =
             dbase.conn.createStatement().executeQuery(query);

             } catch (Exception e){
                 e.printStackTrace();
                 out.println("<br>Error: " + e);
         }
    log.newLine();
    log.write("closing log");
    log.close();
     }

}

     /* display Change Schema Button */
        out.println("<br> <input type='submit' value='Change Schema' " +
                    "onClick=javascript:submitForm('login'); >" );

        /* display Change Park Button */
        out.println("<br> <input type='submit' value='Change Park' " +
        "onClick=javascript:submitForm('selectPark'); >" );

        /* display Change Site Button */
        out.println("<br> <input type='submit' value='Display Sites' " +
                    "onClick=javascript:submitForm('selectSites'); >" );
        out.println("</form>");

out.println("</BODY>");
out.println("</HTML>");

out.close();
}
}

Reply to this Message

Flo 'Irian' Schaetz - 10 Sep 2007 20:59 GMT

And thus spoke jiepie2@gmail.com...

> why does my out put file "log.txt" has the output written twice?

Probably because the 2nd argument is "append", so every time you start
it, it appends the text to the file...?

Flo

Reply to this Message

Roedy Green - 11 Sep 2007 08:31 GMT

>BufferedWriter log = new BufferedWriter (new FileWriter("log.txt",
>true));

should read:

BufferedWriter log = new BufferedWriter (new
FileWriter("log.txt",false));

see http://mindprod.com/applet/fileio.html

Signature

Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

Reply to this Message

jiepie2@gmail.com - 12 Sep 2007 13:44 GMT

On Sep 11, 3:31 am, Roedy Green <see_webs...@mindprod.com.invalid>
wrote:

> On Mon, 10 Sep 2007 12:56:31 -0700, jiep...@gmail.com wrote, quoted or
> indirectly quoted someone who said :
[quoted text clipped - 11 lines]
> Roedy Green Canadian Mind Products
> The Java Glossaryhttp://mindprod.com

hi thanks for replying.

however, i need to the append function, because i want to add more
text the existing file. so therefore i need to do this:
BufferedWriter log = new BufferedWriter (new>
FileWriter("log.txt",true));

one weird thing i found is, my program works in Firefox, but not in IE
7. IE7 simply invoke the servlet twice. do you have solution to this
problem?

Reply to this Message

Roedy Green - 13 Sep 2007 01:52 GMT

>however, i need to the append function, because i want to add more
>text the existing file. so therefore i need to do this:
>BufferedWriter log = new BufferedWriter (new>
>FileWriter("log.txt",true));

Your problem is the browser is free to invoke and shutdown your applet
as many times as it wants. Your code does an append every time it
starts up., so you get "duplicates".

To understand what is going on add some debug code to dump out the
contents of the log.txt just before you open it, or perhaps just the
last few lines if it is voluminous.

Signature

Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

Reply to this Message

kcwong - 13 Sep 2007 08:55 GMT

On Sep 13, 8:52 am, Roedy Green <see_webs...@mindprod.com.invalid>
wrote:

> Your problem is the browser is free to invoke and shutdown your applet
> as many times as it wants. Your code does an append every time it
> starts up., so you get "duplicates".

Er... I went through the OP's first post several times, but I didn't
see anything about an applet... it's a servlet...

Reply to this Message

Roedy Green - 25 Sep 2007 08:48 GMT

>Er... I went through the OP's first post several times, but I didn't
>see anything about an applet... it's a servlet...

You have the same problem with Servlets. The Servlet womb is free to
shut down and restart the Servlet any time it wants to conserve RAM.

You can track this by putting in some static init code to print out a
message every time the class is loaded, and in the constructor to
monitor every time the Servlet is instantiated.

Signature

Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

Reply to this Message

Lew - 25 Sep 2007 15:22 GMT

>> Er... I went through the OP's first post several times, but I didn't
>> see anything about an applet... it's a servlet...
[quoted text clipped - 5 lines]
> message every time the class is loaded, and in the constructor to
> monitor every time the Servlet is instantiated.

You can also make use of the servlet's lifecycle methods, like init().

Signature

Lew

Reply to this Message

when filewriter(file, true) second attribute is true, the output is written twice.?

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