Function calls in JSP / converting servlets

I tried adding functions in the declaration section of a JSP and they were not recogized. Are functions allowed in JSPs?
I'm trying to convert a servlet with multiple functions into a JSP. Is a separate jsp/bean required to do this?

You can declare and use functions in jsp as ..<%!
public String sayHello(String name) {
return "Hello " + name + "!";
%>
<%
%>
<%= sayHello("XYZ") %>

Similar Messages

Function call in JSP

I have a User registration form. User first enters user-ID and password of his choice. This usre-id is checked for availability by the click on a 'Check' Button. On the click event of this button I call the following function checkavail().
<%@page import="Logreg.Regcheck" %>
<script type="text/javascript">
boolean avail=false;
function checkavail()
String user=document.forms[0].userid.value;
boolean ans=(new Regcheck()).checkuser(user,1);
if(ans==false)
document.write("<h3> Username not available </h3>");
else
document.write("<h3> Username available </h3>");
</script>
Logreg.Regcheck is my class that connects to the database and checks. This class is located at WEB_INF/classes/Logreg path. However when I click the button, the GlassFish server doesn't respond.As in, doesn't do anything. The page stands as it is. I presume two issues to be associated with it.
a. An entry of Regcheck class must be made in web.xml. (I don't know XML)
b. docoument.write function is failing to execute.
I have been accessing the database through other servlets, so connectivity problem with the database is definetely out of question. Could you figure what could the problem be?

Hello,
Javascript is Client Browser side scripting Tool. It would not have visibility of any classes under WEB-INF/classes residing on the Server side. You current approach will not work.
Alternatively, if you want this feature, you either have to choose AJAX Call from javascript to the server passing the required information and the server can call the class under WEB-INF/classes folder to do DB operations.
Thanks,
Paz

How to get the value retruned by java script function into my jsp page

Hai all,
I had a particular java script function which returns a date.
function getDate() {
var sDate;
// This code executes when the user clicks on a day in the calendar.
if ("TD" == event.srcElement.tagName)
// Test whether day is valid.
if ("" != event.srcElement.innerText)
//alert(event.srcElement.innerText);
sDate = document.all.year.value + "-" + document.all.month.value + "-" + event.srcElement.innerText;
document.all.ret.value = sDate;
var mahi=window.open("configurexml.jsp?xyz=document.all.ret.value")
return sDate;}
Now i want to display this particular date in my jsp page. can anyone tell me the correct approach or a sample code to diaplay this date in my jsp page.
<%@ page language="java"
import="javax.xml.parsers.*,java.io.*,org.w3c.dom.*"%><%@ page import="java.util.*" %>
!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html> <head> <title>Configuring Xml File</title>
<SCRIPT LANGUAGE="JavaScript" SRC="xyz.js"> </SCRIPT>
body bgcolor="#d0d0d0" onClick= "return getDate()" >
<form name="f1">
<b>20 october 2006 </b>
Here where i am printing the date i had to get the value from the js function. how to do that. plz help me....

Are you talking about server-side java code (servlets/jsp) or client side (applet)? Given we are in the JSP forum I'll assume we're talking server side.
If so, you are making a common but fundamental mistake. JavaScript executes on the client, not on the server. If you want client data on the server it has to get there somehow. The simplest way to do this in JSP land is via HTTP. So... have your JavaScript code call a JSP (or servlet) and pass the value you want as a URL parameter. Of course this will also change the browser location, so if you don't want this to happen use a frame or iframe to capture your HTTP request.
For example:
Javascript....
function someFunction() {
return 1;
var value = someFunction();
location.href="somejsp.jsp?value=" + value;

Problem with cesession.jar: Incompatible object argument for function call

Hi,
I'm looking for an actual file cesession.jar because my current version from BOXI SP2 (01.03.2007 09:22, 62 KB) causes an error.
Who can help me?
Best Regards
Arnold
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: (class: com/crystaldecisions/sdk/framework/internal/d, method: a signature: ()V) Incompatible object argument for function call
     org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:460)
     org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:355)
     org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
     org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
root cause
javax.servlet.ServletException: (class: com/crystaldecisions/sdk/framework/internal/d, method: a signature: ()V) Incompatible object argument for function call
     org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:841)
     org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:774)
     org.apache.jsp.TutorialDesktop.start_jsp._jspService(start_jsp.java:151)
     org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
     org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
     org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
     org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
root cause
java.lang.VerifyError: (class: com/crystaldecisions/sdk/framework/internal/d, method: a signature: ()V) Incompatible object argument for function call
     com.crystaldecisions.sdk.framework.internal.CEFactory.makeSessionMgr(Unknown Source)
     com.crystaldecisions.sdk.framework.CrystalEnterprise.getSessionMgr(Unknown Source)
     org.apache.jsp.TutorialDesktop.start_jsp.createAuthenticationList(start_jsp.java:26)
     org.apache.jsp.TutorialDesktop.start_jsp._jspService(start_jsp.java:132)
     org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
     org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
     org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
     org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
note The full stack trace of the root cause is available in the Apache Tomcat/5.5.26 logs.

Hello Arnold,
Can you provide us the exact information about the implementation version and Ant-version of the cesession.jar file that you are using.
This could be observed by opening the jar file using winrar or winzip, then go to the MANIFEST.MF file present inside META-INF folder.
Once you will open the MANIFEST.MF file, please let us know the first seven lines present inside the same fle.
Thanks,
Chinmay

How can i call userdefined java functions in a JSP ?

Hi,
i want to define some functions in a java class. is it possible to use these functions in a jsp ? how can i achieve this ?

I suggest you call the function you want in either a custom tag or in the servlets/struts/jsf,... classes you are using.
If you dont want those and you prefer scriplets then 2 step,s.
First import the class then call it.

Which part of container actually converts jsp to servlet

hi all,
although it's container's responsibility to convert
jsp to servlet, but can any body tell me
which part of that container is actually
is responsible for this conversion
thanx

At least for Tomcat, the engine that converts a JSP into Java code is Jasper. Then the container has to take the Java code and compile that to a .class file. Once it has that, it keeps reusing the .class file whenever you make a JSP call.
That's why first page access is often slow.
A way to speed it up is to pre-compile your JSPs.
%

Converting JSP to servlet

Hi,
Can anyone show me how to convert my jsp to servlet. Then, from servlet to classes. Thanks.
cheers,

well, jsp pages are converted at run-time to servlets, e.g. if you are using tomcat as jsp engine, you will find the servlet java files somewhere under $TOMCAT_HOME/work/localhost. you can compile these java files to class files.
PS: There is a forum in here for JSP, and I would recommend that you post your questions there in the JSP forum (this one is about databases)

How to call stored function in my jsp

how to call stored function in my jsp?
please give me a example.

Hi,
think we need mor einformation, like JDeveloper release and the how you do access the database (JDBC, BC4J, EJB,ADF...)
Frank

How do i call a function within the jsp?

Hi,
What i am doing is now allow a user to type in comment and when the user click on "Add" button, it will call my function and write to a txt file.How can i call a custom jsp function within my jsp page or what is the correct way to do this?
[My current codes]
<form name="SubmitEvent" method="post" action="addComment()">
</form>
function addComment()
System.out.println("Entered Add Comment function");
Thanks for your help!

You can define a Java Bean (I presume you know the rules to write a Java Bean) and send the read value as parameter to the Bean and then call a function in the Bean from the JSP.
Contact me if you need more help!

How to call a jsp function on a java script event 'onchange'

hi all,
i m in trouble, iwant to call a jsp function on occurance
of a javascript event onchange
actully i want to refresh my one text field at every change
in a select option of a form
plz tel me any othr method if i m wrong.
thnx in adv.

as the form submition is a POST operation u can use some
if{} else{} construct to handle this. u can check the value of some POST variable to identify whether its the first loading or refresh. got it
regards
aleens

How to pass a JSP var to a Script function called in a netui:checkbox

How to pass a JSP variable to a Java Script function called in a netui:checkbox onSelect?
I have a requirement where based on the checkBox selected or deselected in a repeater tag I would have to select or deselect other checkboxes in a netui:form. I am trying to pass the index or unique name of the checkbox to the JavaScript function. When I try this code I am getting a Syntax Error!! and getting a " item undefined" in the javascript. This works when I use just the html form tag but when I use the <netui:form> tag I am facing this issue. Any help would be highly appreciated.
function selectACheckBoxOnClick(name) {
alert ("called selectACheckBoxOnClick ");
alert ("called name "+name);
<netui-data:repeater dataSource="{pageFlow.unregisteredContractAssetsDTOArr}">
<netui-data:repeaterItem>
<% String checkboxName = "selectACheckBox_"+i;
String serialNum = "serialNum_"+i;
String hidenboxName = "hiddenACheckBox_"+i;
String loopNo = new Integer(i).toString();
System.out.println("Loop String :"+ loopNo);
System.out.println("CheckBox Name:"+ checkboxName);
System.out.println("serialNum :"+serialNum); %>
<tr bgcolor="#ffffff">
<td align="center">
<netui:checkBox dataSource="{container.item.selectedAssetFlag}" onSelect="selectACheckBoxOnClick(<%=checkboxName%>);" tagId="<%=checkboxName%>"/>
</td>
          <td class="small"><netui:label value="{container.item.model}"/></td>
          <td class="small">
<netui:hidden dataSource="{container.item.splitAssetNo}" tagId="<%=serialNum%>"/>
<netui:label value="{container.item.serial}"></netui:label></td>
          <td class="small"><netui:label value="{container.item.equpimentId}"/></td>
          <td class="small">
<netui-data:getData resultId="siteId" value="{container.item.siteNo}" />
<%String siteId = (String) pageContext.getAttribute("siteId");%>
<netui:anchor action="getSiteLevelAssets" formSubmit="true">
<netui:parameter value="{container.item.siteNo}" name="siteNo" />
<netui:label value="{container.item.siteNo}" />
</netui:anchor>
</td>     </tr>
<%i++;%>
</netui-data:repeaterItem>
</netui-data:repeater>
This code works within a form:
               <td align=center>
                    <input type=image name="unassign" onclick="javascript:unassignReplacement(<%=replacementSupply.getPMSupplyId()%>)" src="<%=request.getContextPath()%>/images/bt_sm_x.gif" border=0 alt="Unassign">
                    </td>
Thanks,
Salome

hi
i did not go thru your code completly
but u can use the following for your problem
the checkbox in the repeater must have unique TagID
counter = 0; (initialize)
<netui-data:repeaterItem>
<netui:checkBox dataSource="" tagId='<%="count"+String.valueOf(counter)%>' onClick="some function()" />
<%counter++;%>
</netui-data:repeaterItem>
here if u have 3 checkbox
They will have Tagid's as count1 , count2 and count3
now in the javascript somefunction()
use the following line
for(j=0;j<<%=counter%>;j++)
document.forms(0)[getNetuiTagName"count"+j)].checked=false;
}

Adding a Button a Servlet that calls a JSP

How would one put a Button in a Servlet that directs to a JSP.
... I have created a servlet that displays records from a database, but I would like to add a button that returns to a JSP page.
I thought something like this would help...
out.println("<input type='submit' value='Return to Main Page' name='response.sendRedirect ('MainPage.jsp');'/>");Help...
Edited by: Gusha on 11-Oct-2008 13:23

You edited your message with a code snippet:
Gusha wrote:
out.println("<input type='submit' value='Return to Main Page' name='response.sendRedirect ('MainPage.jsp');'/>");
Couple of things:
1) Presentation logic belongs in JSP, not in Servlet. Using out.print in either JSP or Servlet is a bad practice.
2) Java runs at server side, not at client side.

Java.lang.VerifyError - Incompatible object argument for function call

Hi all,
I'm developing a JSP application (powered by Tomcat 4.0.1 in JDK 1.3, in Eclipse 3.3). Among other stuff I have 3 classes interacting with an Oracle database, covering 3 use cases - renaming, adding and deleting an database object. The renaming class simply updates the database with a String variable it receives from the request object, whereas the other two classes perform some calculations with the request data and update the database accordingly.
When the adding or deleting classes are executed, by performing the appropriate actions through the web application, Tomcat throws the following:
java.lang.VerifyError: (class: action/GliederungNewAction, method: insertNewNode signature: (Loracle/jdbc/driver/OracleConnection;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;I)V) Incompatible object argument for function call
     at java.lang.Class.forName0(Native Method)
     at java.lang.Class.forName(Class.java:120)
     at action.ActionMapping.perform(ActionMapping.java:53)
     at ControllerServlet.doResponse(ControllerServlet.java:92)
     at ControllerServlet.doPost(ControllerServlet.java:50)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
     at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
...The renaming works fine though. I have checked mailing lists and forums as well as contacted the company's java support but everything I have tried out so far, from exchanging the xerces.jar files found in JDOM and Tomcat to rebuidling the project didn't help.
I just can't explain to myself why this error occurs and I don't see how some additional Java code in the other 2 classes could cause it?
I realize that the Tomcat and JDK versions I'm using are totally out of date, but that's company's current standard and I can't really change that.
Here's the source code. I moved parts of the business logic from Java to Oracle recently but I left the SQL statements that the Oracle stored procedures are executing if it helps someone.
package action;
import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.StringTokenizer;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import oracle.jdbc.driver.OracleConnection;
* This class enables the creation and insertion of a new catalogue node. A new node
* is always inserted as the last child of the selected parent node.
public class GliederungNewAction implements Action {
     public String perform(ActionMapping mapping, HttpServletRequest request,
               HttpServletResponse response) {
          // fetch the necessary parameters from the JSP site
          // the parent attribute is the selected attribute!
          String parent_attribute = request.getParameter("attr");
          String catalogue = request.getParameter("catalogue");
          int parent_sequenceNr = Integer.parseInt(request.getParameter("sort_sequence"));
          // connect to database
          HttpSession session = request.getSession();
          db.SessionConnection sessConn = (db.SessionConnection) session.getAttribute("connection");
          if (sessConn != null) {
               try {
                    sessConn.setAutoCommit(false);
                    OracleConnection connection = (OracleConnection)sessConn.getConnection();
                    int lastPosition = getLastNodePosition( getLastChildAttribute(connection, catalogue, parent_attribute) );
                    String newNodeAttribute = createNewNodeAttribute(parent_attribute, lastPosition);
                    // calculate the sequence number
                    int precedingSequenceNumber = getPrecedingSequenceNumber(connection, catalogue, parent_attribute);
                    if ( precedingSequenceNumber == -1 ) {
                         precedingSequenceNumber = parent_sequenceNr;
                    int sortSequence = precedingSequenceNumber + 1;
                    setSequenceNumbers(connection, catalogue, sortSequence);
                    // insert the new node into DB
                    insertNewNode(connection, catalogue, newNodeAttribute, parent_attribute, "Neuer Punkt", sortSequence);
                    connection.commit();
               } catch(SQLException ex) {
                    ex.printStackTrace();
          return mapping.getForward();
      * Creates, fills and executes a prepared statement to insert a new entry into the specified table, representing
      * a new node in the catalogue.
     private void insertNewNode(OracleConnection connection, String catalogue, String attribute, String parent_attribute, String description, int sortSequence) {
          try {
               String callAddNode = "{ call fasi_lob.pack_gliederung.addNode(:1, :2, :3, :4, :5) }";
               CallableStatement cst;
               cst = connection.prepareCall(callAddNode);
               cst.setString(1, catalogue);
               cst.setString(2, attribute);
               cst.setString(3, parent_attribute);
               cst.setString(4, description);
               cst.setInt(5, sortSequence);
               cst.execute();
               cst.close();
          } catch (SQLException e1) {
               // TODO Auto-generated catch block
               e1.printStackTrace();
//          String insertNewNode = "INSERT INTO vstd_media_cat_attributes " +
//                    "(catalogue, attribute, parent_attr, description, sort_sequence) VALUES(:1, :2, :3, :4, :5)";
//          PreparedStatement insertStmt;
//          try {
//               insertStmt = connection.prepareStatement(insertNewNode);
//               insertStmt.setString(1, catalogue);
//               insertStmt.setString(2, attribute);
//               insertStmt.setString(3, parent_attribute);
//               insertStmt.setString(4, description);
//               insertStmt.setInt(5, sortSequence);
//               insertStmt.execute();
//               insertStmt.close();
//          } catch (SQLException e) {
//               e.printStackTrace();
      * This method returns the attribute value of the last child of the parent under which
      * we want to insert a new node. The result set is sorted in descending order and only the
      * first result (that is, the last child under this parent) is fetched.
      * If the parent node has no children, "parent_attr.0" is returned.
      * @param connection
      * @param catalogue
      * @param parent_attribute
      * @return attribute of the last child under this parent, or "parent_attr.0" if parent has no children
     private String getLastChildAttribute(OracleConnection connection, String catalogue, String parent_attribute) {
          String queryLastChild = "SELECT attribute FROM vstd_media_cat_attributes " +
                                        "WHERE catalogue=:1 AND parent_attr=:2 ORDER BY sort_sequence DESC";
          String lastChildAttribute;
          PreparedStatement ps;
          try {
               ps = connection.prepareStatement(queryLastChild);
               ps.setString(1, catalogue);
               ps.setString(2, parent_attribute);
               ResultSet rs = ps.executeQuery();
               /* If a result is returned, the selected parent already has children.
                * If not set the lastChildAttribute to parent_attr.0
               if (rs.next()) {
                    lastChildAttribute = rs.getString("attribute");
               } else {
                    lastChildAttribute = parent_attribute.concat(".0");
               rs.close();
               return lastChildAttribute;
          } catch (SQLException e) {
               e.printStackTrace();
               return null;
      * This helper method determines the position of the last node in the attribute.
      * i.e for 3.5.2 it returns 2, for 2.1 it returns 1 etc.
      * @param attribute
      * @return position of last node in this attribute
     private int getLastNodePosition(String attribute) {
          StringTokenizer tokenizer = new StringTokenizer(attribute, ".");
          String lastNodePosition = "0";
          while( tokenizer.hasMoreTokens() ) {
               lastNodePosition = tokenizer.nextToken();
          return Integer.parseInt(lastNodePosition);
      * This method calculates the attribute of a node being inserted
      * by incrementing the last child position by 1 and attaching the
      * incremented position to the parent.
      * @param parent_attr
      * @param lastPosition
      * @return attribute of the new node
     private String createNewNodeAttribute(String parent_attr, int lastPosition) {
          String newPosition = new Integer(lastPosition + 1).toString();
          return parent_attr.concat("." + newPosition);
      * This method checks if the required sequence number for a new node is already in use and
      * handles the sequence numbers accordingly.
      * If the sequence number for a new node is NOT IN USE, the method doesn't do anything.
      * If the sequence number for a new node is IN USE, the method searches for the next free
      * sequence number by incrementing the number by one and repeating the query until no result
      * is found. Then all the sequence numbers between the required number (including, >= relation)
      * and the nearest found free number (not including, < relation) are incremented by 1, as to
      * make space for the new node.
      * @param connection
      * @param catalogue
      * @param newNodeSequenceNumber required sequence number for the new node
     private void setSequenceNumbers(OracleConnection connection, String catalogue, int newNodeSequenceNumber) {
          // 1. check if the new sequence number exists - if no do nothing
          // if yes - increment by one and see if exists
          //           repeat until free sequence number exists
          // when found increment all sequence numbers freeSeqNr > seqNr >= newSeqNr
          String query = "SELECT sort_sequence FROM vstd_media_cat_attributes " +
                    "WHERE catalogue=:1 AND sort_sequence=:2";
          PreparedStatement ps;
          try {
               ps = connection.prepareStatement(query);
               ps.setString(1, catalogue);
               ps.setInt(2, newNodeSequenceNumber);
               ResultSet rs = ps.executeQuery();
               // if no result, the required sequence number is free - nothing to do
               if( rs.next() ) {
                    int freeSequenceNumber = newNodeSequenceNumber;
                    do {
                         ps.setString(1, catalogue);
                         ps.setInt(2, freeSequenceNumber++);
                         rs = ps.executeQuery();
                    } while( rs.next() );
                    // increment sequence numbers - call stored procedure
                    String callUpdateSeqeunceNrs = "{ call fasi_lob.pack_gliederung.updateSeqNumbers(:1, :2, :3) }";
                    CallableStatement cst = connection.prepareCall(callUpdateSeqeunceNrs);
                    cst.setString(1, catalogue);
                    cst.setInt(2, newNodeSequenceNumber);
                    cst.setInt(3, freeSequenceNumber);
                    cst.execute();
                    cst.close();
//                    String query2 = "UPDATE vstd_media_cat_attributes " +
//                                      "SET sort_sequence = (sort_sequence + 1 ) " +
//                                      "WHERE catalogue=:1 sort_sequnce >=:2 AND sort_sequence <:3";
//                    PreparedStatement ps2;
//                    ps2 = connection.prepareStatement(query2);
//                    ps2.setString(1, catalogue);
//                    ps2.setInt(2, newNodeSequenceNumber);
//                    ps2.setInt(3, freeSequenceNumber);
//                    ps.executeUpdate();
//                    ps.close();
               } // end of if block
               rs.close();
          } catch (SQLException e) {
               e.printStackTrace();
      * This method finds the last sequence number preceding the sequence number of a node
      * that is going to be inserted. The preceding sequence number is required to calculate
      * the sequence number of the new node.
      * We perform a hierarchical query starting from the parent node: if a result is returned,
      * we assign the parent's farthest descendant's node sequence number; if no result
      * is returned, we assign the parent's sequence number.
      * @param connection
      * @param catalogue
      * @param parent_attr parent attribute of the new node
      * @return
     private int getPrecedingSequenceNumber(OracleConnection connection, String catalogue, String parent_attr) {
          int sequenceNumber = 0;
          String query = "SELECT sort_sequence FROM vstd_media_cat_attributes " +
                            "WHERE catalogue=:1 " +
                            "CONNECT BY PRIOR attribute = parent_attr START WITH parent_attr=:2 " +
                            "ORDER BY sort_sequence DESC";
          try {
               PreparedStatement ps = connection.prepareStatement(query);
               ps.setString(1, catalogue);
               ps.setString(2, parent_attr);
               ResultSet rs = ps.executeQuery();
               if ( rs.next() ) {
                    sequenceNumber = rs.getInt("sort_sequence");
               } else {
                    // TODO: ggf fetch from request!
                    sequenceNumber = -1;
               rs.close();
               ps.close();
          } catch (SQLException e) {
               e.printStackTrace();
          return sequenceNumber;
}

After further googling I figured out what was causing the problem: in eclipse I was referring to external libraries located in eclipse/plugins directory, whereas Tomcat was referring to the same libraries (possibly older versions) in it's common/lib directory.

Showing various images on browser using JSP and Servlet

Hello Guys!
I am starting to develop in Java and already I am facing a big problem.
If somebody will have some tip or suggestion, will be very well comings!
The application must present in browser images originnally of format TIF. As it is not a native format of the I.E. , I converted the image for JPG (without saving it on disk) and send it to the browser a encoded image (encode) using JAI library in one servlet had access by a JSP. Then, the structure of my application is thus:
1) an archive JSP draws the initial screen in browser and presents one input text.
2) later that the user places the parameter, I make an access to the database and read a quantity of images to be presented.
3) From there in the proper JSP, I use de tag img src to send image to the browser in agreement archive the amount of images.
It follows the code of the JSP:
<%
                int intI=0;
                int intCont=0;
                if(blnImagem == true){
                    out.println("<br>");
                    out.println("<table border=0 STYLE=border-collapse:collapse>");
                    out.println("<tr>");
                    for(intI=0;intI < Processo.intQtdImagens;intI++){
                       Imagem.strImgTif = Imagem.IndicarImagem(Processo.strNmPath,Processo.strSubPath,Processo.intNuImagem,intI);
                       out.println("<th>");
                       out.println("<table border=1 STYLE=border-collapse:collapse rules='cols'>");
                       out.println("<tr>");
                       out.println("<th>");
                       %>
                         <img src="ShowImg" WIDTH=100>
                       <%
                       out.println("</th>");
                       out.println("</tr>");
                       out.println("</table>");
%>and code on the ShowImg servlet:
        response.setContentType("image/jpeg");
        ServletOutputStream sos = response.getOutputStream();
        RenderedOp src = JAI.create("fileload", Imagem.strImgTif);
        ImageEncoder encoder = ImageCodec.createImageEncoder("JPEG",sos,null);
        encoder.encode(src);
        sos.close();The problem is if I have 10 images to present, it WILL BE it is executed 10 times and it passes 10 names of different archives, but in the page only the last image is presented 10 times. It is as if it processed the TAG to the end of everything in way that the value of the static variable Imagem.strImgTif was chore only with the last value and the same loaded image 10 times. How I make to solve this? Somebody has some idea?
THANK YOU !
Emidio

If I understand correctly what your problem is:
Do this in the jsp:
out.println("<img src=\"ShowImg?image=" + intI + "\" WIDTH=100>");
In the image servlet, get the "image" parameter and parse it as an int. Move the Imagem.IndicarImagem() call to the image servlet.

Problem with multiple Ajax calls to the same Servlet

Hi,
I am new to AJAX. I have a requirement where in, i have to make ajax calls to the same servlet in an infinite loop and check for an application context attribute to refresh the contents in the JSP.I am using the following script in JSP. The problem is i am not able to invoke the servlet more than one time.But I am able to go through the script at specific time interval using setInterval() function of Javascript and able to get alerts.But the problem is with xmlhttp.open("Get", url, true);. Its not getting called more than one time, even though i make multiple calls to the function.
*<script type="text/javascript">*
var xmlhttp
var resp
function fAjax()
alert("Here");
xmlhttp=null;
resp=null;
// code for Mozilla, etc.
if (window.XMLHttpRequest)
xmlhttp=new XMLHttpRequest();
// code for IE
else if (window.ActiveXObject)
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
if (xmlhttp!=null)
xmlhttp.onreadystatechange=state_Change;
xmlhttp.open("GET","/PSAPBackOffice/TestServlet",true);
xmlhttp.send(null);
else
alert("Your browser does not support XMLHTTP.")
function state_Change()
// if xmlhttp shows "loaded"
if (xmlhttp.readyState==4)
// if "OK"
if (xmlhttp.status==200)
     resp=xmlhttp.responseText;
     //alert(resp);
     if (resp=="CALL"){
     form.method="GET";
     form.action="/Project/Details.jsp
form.submit();
else
alert("Problem retrieving XML data")
function callTimer(){
     setInterval("fAjax()",5000);
*</script>*
*Code for Servlet here:*
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException
ServletContext objContext= getServletContext();
     String value;
     synchronized (objContext) {
               value=(String) objContext.getAttribute("Flag");
                    if(value==null){
                    else if(value.equals("Done")){
                         response.setContentType(CONTENT_TYPE);
                         PrintWriter out = null;
                              try {
                                   out = response.getWriter();
                              } catch (IOException e) {
                                   // TODO Auto-generated catch block
                                   e.printStackTrace();
                                                            } catch (NullPointerException npe) {
                                   // TODO Auto-generated catch block
                                   npe.printStackTrace();
                         objContext.setAttribute("Flag","No");
                         out.println("CALL");
Can someone figureout the problem or mistake and help me out.Its urgent and please help me in this regard.Thanks in Advance !

I'm not sure I'm following you. The mapping from URL to servlet can contain anything you want. So you could have the URL /blah/blah/blah that, with a mapping something like /blah/* would pass all requests with that URL pattern to your servlet - no one has to know it is a servlet. Your servlet could then parse the URL to see what it has to do or you could pass parameters as part of the URL or as hidden fields.

Function calls in JSP / converting servlets

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