Using javabeans in servlets

Hi,
          I am trying to write a simple web application where I have an entity bean
          that encapsulates a database table, a servlet that queries the table and
          sends back entity ejbs. I want to display the query results in a user
          friendly way. I am planning to write a JavaBean that contains a JTable and
          use that JavaBean in the servlet.
          Will using a swing component have any impact on the performance of the
          servlet?
          I am just wondering if there is a better way?
          Thanks
          Shalini

Will using a swing component have any impact on the performance of the          > servlet?
          Unless I misunderstand, the JTable is on the client (Java app or browser
          applet) and the database table is being accessed by the servlet on the
          server, so the JTable will not affect the performance of the Servlet, since
          they are on different machines and working in a rather unrelated manner.
          Cameron Purdy
          [email protected]
          http://www.tangosol.com
          WebLogic Consulting Available
          "beaservlets" <[email protected]> wrote in message
          news:39c811b3$[email protected]..
          > Hi,
          > I am trying to write a simple web application where I have an entity bean
          > that encapsulates a database table, a servlet that queries the table and
          > sends back entity ejbs. I want to display the query results in a user
          > friendly way. I am planning to write a JavaBean that contains a JTable and
          > use that JavaBean in the servlet.
          >
          > Will using a swing component have any impact on the performance of the
          > servlet?
          >
          > I am just wondering if there is a better way?
          >
          > Thanks
          > Shalini
          >
          >

Similar Messages

Using JavaBeans in a JSP Page

I wan't to know the advantages and disadvantages of using JavaBeans in a JSP page.
Like for example general traditional approach for a database connection
is to create a connection and access the database from that and close the connection
at the end of the page, instead of the If I use a common connection bean for making connections,
is that suggestable and then when should i close the connection then.
One good application of JavaBeans is using a Set and Get methods for form fields in
a registration form to get back the values.
So may i know how best can we use the JavaBeans other than this application.
ThanX in advance,
kiran
[email protected]

I believe putting processing and query code in the JavaBean was one of the reasons for putting JavaBeans support in JSP in the first place. The original idea was to use the setXXX methods to populate the bean's data from the posted form, then do the processing (or database query), then use the getXXX methods to display the bean's data.
Efficiency-wise, it's exactly the same as putting all the code in-line in the JSP page (actually, it might be a bit slower, because of the reflection required to do it.) Code-wise though, it makes the JSP easier to read.
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Using javabean in tomcat(unable to compile class)

Hello, I am using jakarta-tomcat-5.0.28, OS:WinXP
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THE ERROR IS:
==============================================================
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: Unable to compile class for JSP
An error occurred at line: 1 in the jsp file: /SaveName.jsp
Generated servlet error:
C:\Programs\internet\jakarta-tomcat-5.0.28\work\Catalina\localhost\JSPSession\org\apache\jsp\SaveName_jsp.java:42: cannot resolve symbol
symbol : class UserData
location: class org.apache.jsp.SaveName_jsp
UserData user = null;
^
An error occurred at line: 1 in the jsp file: /SaveName.jsp
Generated servlet error:
C:\Programs\internet\jakarta-tomcat-5.0.28\work\Catalina\localhost\JSPSession\org\apache\jsp\SaveName_jsp.java:44: cannot resolve symbol
symbol : class UserData
location: class org.apache.jsp.SaveName_jsp
user = (UserData) jspxpage_context.getAttribute("user", PageContext.SESSION_SCOPE);
^
An error occurred at line: 1 in the jsp file: /SaveName.jsp
Generated servlet error:
C:\Programs\internet\jakarta-tomcat-5.0.28\work\Catalina\localhost\JSPSession\org\apache\jsp\SaveName_jsp.java:46: cannot resolve symbol
symbol : class UserData
location: class org.apache.jsp.SaveName_jsp
user = new UserData();
^
3 errors
     org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:84)
     org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:332)
     org.apache.jasper.compiler.Compiler.generateClass(Compiler.java:412)
     org.apache.jasper.compiler.Compiler.compile(Compiler.java:472)
     org.apache.jasper.compiler.Compiler.compile(Compiler.java:451)
     org.apache.jasper.compiler.Compiler.compile(Compiler.java:439)
     org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:511)
     org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:295)
     org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
     org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
     javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
note The full stack trace of the root cause is available in the Apache Tomcat/5.0.28 logs.
===============================================================
ERROR END
I use the folowing files:
GetName.html
SaveName.jsp
NextPage.jsp
UserData.java
My Dir Structure is:
/JSPSession
    GetName.html
     SaveName.jsp
     NextPage.jsp
   /WEB-INF
      /classes
         UserData.java
         UserData.class
   /libThe Code for the files is:
GetName.html
<HTML>
<BODY>
<FORM METHOD=POST ACTION="SaveName.jsp">
What's your name? <INPUT TYPE=TEXT NAME=username SIZE=20><BR>
What's your e-mail address? <INPUT TYPE=TEXT NAME=email SIZE=20><BR>
What's your age? <INPUT TYPE=TEXT NAME=age SIZE=4>
<P><INPUT TYPE=SUBMIT>
</FORM>
</BODY>
</HTML>---------------------------------------------------------------------------------------------------
SaveName.jsp
<jsp:useBean id="user" class="UserData" scope="session"/>
<jsp:setProperty name="user" property="*"/>
<HTML>
<BODY>
<A HREF="NextPage.jsp">Continue</A>
</BODY>
</HTML>-----------------------------------------------------------------------------------------------------
NextPage.jsp
<jsp:useBean id="user" class="UserData" scope="session"/>
<HTML>
<BODY>
You entered<BR>
Name: <%= user.getUsername() %><BR>
Email: <%= user.getEmail() %><BR>
Age: <%= user.getAge() %><BR>
</BODY>
</HTML>------------------------------------------------------------------------------------------------------------
UserData.java
public class UserData {
    String username;
    String email;
    int age;
    public void setUsername( String value ) {
        username = value;
    public void setEmail( String value ) {
        email = value;
    public void setAge( int value ) {
        age = value;
    public String getUsername() { return username; }
    public String getEmail() { return email; }
    public int getAge() { return age; }
}

A very common question. Tomcat dislikes classes which are not packaged. So, add a package statement in your UserBean.java
package beans; // or something like thatand then place the compiled class file UserBean.class into WEB-INF/classes/beans.
Put the import statement into the JSP accordingly and try again.
***Annie***

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bye..

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Experts,
I am new to JavaBean(not EJB), and wondering what is the difference of using JavaBean for JSP page compared with using regular Java class?
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No.
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(-:

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