Problem in accessing object using Expression Language

Hello All,
Im using Tomcat 5.5 and I am learning Expression language.Im using one servlet page as login.java i.e,
package common;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import javax.servlet.RequestDispatcher;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import Database.DatabaseObject;
import valueobjects.login1;
public class login extends HttpServlet {
     public static final long serialVersionUID = 8707690322213556804l;
     public void doPost(HttpServletRequest req, HttpServletResponse res) {
          String name = req.getParameter("username");
          String password = req.getParameter("password");
          RequestDispatcher dispatch = null;
          ResultSet rs=null;
          Statement st=null;
          login1 log=null;
          Connection con = null;
          String sql=null;
          try
          con=new DatabaseObject().getConnection();
          st = con.createStatement();
          sql="select * from login";
          System.out.println(sql);
          rs=st.executeQuery(sql);
          while(rs.next())
               log=new login1(rs.getString("User_Name"),rs.getString("user_Password"));
          req.setAttribute("login",log);
          req.setAttribute("username",name);
          req.setAttribute("password",password);
          dispatch = req.getRequestDispatcher("/jsps/el.jsp");
          dispatch.forward(req, res);
          catch(Exception e)
               e.printStackTrace();
That login1 customized object is set as ,
package valueobjects;
public class login1{
     String Name;
     String Password;
     public login1(String name, String password) {
          super();
          // TODO Auto-generated constructor stub
          Name = name;
          Password = password;
     public String getName() {
          return Name;
     public void setName(String name) {
          this.Name = name;
     public String getPassword() {
          return Password;
     public void setPassword(String password) {
          this.Password = password;
then im using one jsp as el.jsp that is,
<%@ page isELIgnored="false"%>
<%@ page import = "java.util.*,valueobject.*"%>
<html>
<jsp:useBean id="login" class="valueobjects.login1">
<jsp:setProperty name="login" property="name" value="username"/>
<jsp:setProperty name="login" property="password" value="password"/>
</jsp:useBean>
<body>
     <center>
     username=${login.Name}<br><br>
     </center>
</body>
</html>
but when i execute this code it is giving error as
/jsps/el.jsp(4,0) The value for the useBean class attribute valueobjects.login1 is invalid.
But that login1.java is in correct package that is valueobjects.but im not getting why it is giving such error.Plz help me.

hi
to use java bean u MUST follow the two conviosions:
1. the class u want to make a bean from it must have no-argument constructor
2. u must provide setter and getter for every instance variable , the name of instance varible must begin with small letter and its setter and getter must be like setXxx() and getXxx()
the correct bean is :
package valueobjects;
     public class login1{
     String name;
     String password;
     public String getName()
               return name;
     public void setName(String name)
               this.name = name;
     public String getPassword()
                return password;
     public void setPassword(String password)
                this.password = password;
     }where is my duke's $ ???

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</body></head>
It just shows " Hi there! 3 + 3 is ${3+3} " as the output. I tried google search. it seems the problem is across many networks like in bea weblogic etc.,
when i used <%@page isELEnabled="true" > i get an error saying attribute isELEnabled not recognised or something like that. My web.xml hasn't got any setting for jsp so I don't know where the "*.jsp" section is available, just in case that needs any touchup.
I have installed JSTL under /common/lib dir. but i think this library is not required for using basic EL.
So, can anyone help me configure my JSP page so that i can use EL tags in them.
OS: Windows 2000
Tomcat ver: 5
J2Se: 1.5 beta

Hmmm. Looks like I didn't make myself clear enough.
You still have the declaration DTD for servlet 2.3 at the top of your web.xml.
To enable EL using Tomcat 5 you only need to do ONE of the following:
1 - update your web.xml file to have the header for the 2.4 version (note its not a DTD anymore)
2 - if your web.xml uses the DTD from version 2.3, include the page directive <%@ page isELIgnored="false" %> on any pages
Basically the rules for executing EL are as follows:
1 - Is there a directive on the page? If yes, then enable/disable according to the directive.
2 - Is there an entry in web.xml for handling EL? If yes then enable/disable according to the setting
3 - Is the web.xml file for the Servlet 2.4 spec? (ie does it start have the version 2.4 header) Yes = enable EL No = disable EL
The easiest way of enabling EL is updating your web.xml to be compliant with the latest servlet spec.
Cheers,
evnafets

Reading Objects using NIO

I having problems reading an object using NIO APIs. I am end creating an Object and pass it through a socket. When I retrieve the data from the input stream within the socket I initialize a ByteBuffer by allocating a length. The problem is that there is NO way of knowing what to allocate that ByteBuffer when reading in the object. Below is within a method that allows me to read information from the socket.
//Allocate the length ByteBuffer.
ByteBuffer buffer = ByteBuffer.allocate(1024);
//Read the data from the SocketChannel....PROBLEM IS WHAT IF I NEED TO DO MULTIPLE READS
socketChannel.read(buffer);
///We will create a byte array from the ByteBuffer.
byte[] b = buffer.array();
//ByteArrayInputStream that we will create and put the byte array in.
ByteArrayInputStream bis = new ByteArrayInputStream(b);
//ObjectInputStream where we will use the ByteArrayInputStream.
ObjectInputStream input = new ObjectInputStream(bis);
//Object that we will read in.
Object obj = input.readObject();
//Message that we will end up receiving.
Message receivingMsg = null;
//Once we have our Message we will end up closing the connection.
bis.close();
input.close();
//We will clear the buffer.
buffer.clear();
//We will cast the object to a message object so
//that we can end up sending it through the right
//routine which will allow us to send a response
//back to the client. *********SPECIAL Class that will cast our generic object into a Message Object.
Message receivedFromClient = (Message) obj;
//we will end up taking that message and returning it.
Message returningMsg = communicate(receivedFromClient);
//Here we will end up taking the Message and putting it into the ByteBuffer.
ByteBuffer bb = objectToOutputStreamByteBuffer(returningMsg);
socketChannel.write(bb);
----The problem is if I have more data within that Object. I need to re-allocate the ByteBuffer object and read everything on that socket. I tried the following code but I really don't feel it will be optimized the best for performance. I guess my question is that should I even be using NIO in this situation or Blocking IO?
Again, here is the code that will read multiple data from the socket until it is -1.
//Here we will read the information we received by first allocating
//a ByteBuffer object.
ByteBuffer buffer1 = ByteBuffer.allocate(5);
ByteBuffer buffer2 = ByteBuffer.allocate(0);
//We will read the data from this object.
while ((socketChannel.read(buffer1)) != -1) {
//We will check the Buffers and then try to recreate a new ByteBuffer that will put the remaining
//stuff within the buffer. NOT SURE IF THIS IS THE MOST EFFICIENT WAY OF DOING THIS
//AND ACTUALLY DON'T HAVE THE CODE WORKING CORRECTLY. THIS IS WHERE I
//NEED HELP ON THE CORRECT WAY TO DO THIS.
     if (buffer1.remaining() < buffer2.remaining()) {
          buffer1.flip();
          buffer2 = ByteBuffer.allocate(buffer1.remaining() + buffer2.remaining());
          System.out.println("tmp 2 Remaining : " + buffer2.remaining());
          //tmp.put(buffer2);
          //buffer2 = tmp;
          System.out.println("Buffer 2 Remaining : " + buffer2.remaining());
     buffer2.put(buffer1);
     buffer1.clear();
//We will create a byte array from the ByteBuffer.
byte[] b = buffer.array();
//ByteArrayInputStream that we will create and put the byte array in.
ByteArrayInputStream bis = new ByteArrayInputStream(b);
//ObjectInputStream where we will use the ByteArrayInputStream.
ObjectInputStream input = new ObjectInputStream(bis);
//Object that we will read in.
Object obj = input.readObject();
//Message that we will end up receiving.
Message receivingMsg = null;
//Once we have our Message we will end up closing the connection.
bis.close();
input.close();
//We will clear the buffer.
buffer2.clear();
buffer1.clear();
//We will cast the object to a message object so
//that we can end up sending it through the right
//routine which will allow us to send a response
//back to the client.
Message receivedFromClient = (Message) obj;
//we will end up taking that message and returning it.
Message returningMsg = communicate(receivedFromClient);
//Here we will end up taking the Message and putting it into the ByteBuffer.
ByteBuffer bb = objectToOutputStreamByteBuffer(returningMsg);
socketChannel.write(bb);
Any help would be greatly appreciated.

I use my own InputStream class overriding the two standard read functions read( byte[], index, length ) and read(). When you construct it pass in the channel you are reading from and read from the channel on demand. ie when a call to read comes in you read say 100 bytes from the channel. The call required only 80 so these are consumed and the other 20 are buffered. Another read call is made, this time for 50 bytes but we only have 20 buffered so another read of the channel is needed. It is up to you whether you break the contract of read( byte[], index, length ) to keep reading the channel until the full "length" is available, or handle this in your application code.
Then because this class is InputStream you can wrap it up inside any stream you like such as the ObjectInputStream and the data will be serialized correctly.

Problem in accessing object using Expression Language

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