Not able to see details of objects in struts iterator in JSP

[Ankit Tripathi]

Hi all,

I have followed a tutorial(struts2,spring and hibernate integration)(set of code snippets) on a website and tried to develop below example according to my needs but I am not able to see appropriated details in view(JSP).

Even after referring to original resource and many other resources I am not able to figure out the issue.

I have copied/attached code snippets and screen-shot of view(JSP) below :

Commentor.java(Hibernate Entity Class)

package com.ankit.model;

import java.util.ArrayList;
import java.util.Date;

import org.apache.log4j.Logger;

import com.ankit.controller.LoginServlet;

public class Commentor implements java.io.Serializable {
	private String name;
	private String comment;
	private Date createdDate;
	private Long commentorId;

	Logger logger = Logger.getLogger(Commentor.class);
	
	public void setCommentorId(Long commentorId) {
		this.commentorId = commentorId;
		
		//logger.info("In Entity Class- ID-setter method: "+this.commentorId);
	}
	public Long getCommentorId() {
		
		logger.info("In Entity Class- ID-getter method:");
		return commentorId;
	}
	public void setName(String name) {
		this.name = name;
		//logger.info("In Entity Class- Name-setter method: "+this.name);
	}
	public String getName() {
		
		logger.info("In Entity Class- Name-getter method:");
		return name;
	}
	public void setComment(String comment) {
		this.comment = comment;
		
		//logger.info("In Entity Class-comment-setter method : "+this.comment);
	}
	public String getComment() {
		
		logger.info("In Entity Class- Comment-getter method:");
		return comment;
	}
	public void setCreatedDate(Date createdDate) {
		this.createdDate = createdDate;
		//logger.info("In Entity Class-creation date-setter method : "+this.createdDate);
	}
	
	public Date getCreatedDate() {
		
		logger.info("In Entity Class- creation date-getter method:");
		return createdDate;
	}
	
}

CommentorAction.java(Struts Action Class)

package com.ankit.action;
 
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import org.apache.log4j.Logger;
 
import com.ankit.controller.LoginServlet;
import com.ankit.model.interfaces.CommentorBo;
import com.ankit.model.Commentor;
import com.opensymphony.xwork2.ModelDriven;
 
public class CommentorAction implements ModelDriven{ 
	Logger logger = Logger.getLogger(CommentorAction.class);
	Commentor commentor = new Commentor();
	List<Commentor> commentorList = new ArrayList<Commentor>();
 
	CommentorBo commentorBo;
	//DI via Spring
	public void setCommentorBo(CommentorBo commentorBo) {
		this.commentorBo = commentorBo;
		
		logger.info("In Action Class- CommentorBo-setter method: "+this.commentorBo);
	}
 
	public Object getModel() {
		
		logger.info("In Action Class- Model-getter method:");
		return commentor;
	}
      
	public List<Commentor> getcommentorList() {
		
		logger.info("In Entity Class- commentorList-getter method:");
		return commentorList;
	}
 
	public void setcommentorList(List<Commentor>commentorList) {
		this.commentorList = commentorList;
		
		logger.info("In Action Class- commentorList-setter method: "+this.commentorList);
	}
	//save commentor
	public String addCommentor() throws Exception{
                commentor.setCreatedDate(new Date());
		commentorBo.addCommentor(commentor);
		commentorList = null;
		commentorList = commentorBo.listCommentor();
		logger.info("In Action Class- commentorList-addCommentor method: "+commentorList);
	        return "success";
		}
          //list commentor
	public String listCommentor() throws Exception {
		
               commentorList = commentorBo.listCommentor();
	       logger.info("In Action Class- commentorList-listCommentor method: "+commentorList.toString());
               return "success";
		}
	}

CommentorBoImpl(Service class implementing interface CommentorBo)

package com.ankit.model;

import java.util.List;

import org.apache.log4j.Logger;

import com.ankit.model.interfaces.CommentorBo;

import com.ankit.controller.LoginServlet;
import com.ankit.dao.CommentorDAO;

import com.ankit.model.Commentor;

public class CommentorBoImpl implements CommentorBo {
	Logger logger = Logger.getLogger(CommentorBoImpl.class);
	
	CommentorDAO commentorDAO;
	//DI via Spring
	public void setCommentorDAO(CommentorDAO commentorDAO) {
		this.commentorDAO = commentorDAO;
		
		logger.info("In Business Object Class- CommentorDAO-setter method: "+this.commentorDAO);
	}
 
	//call DAO to save commentor
	public void addCommentor(Commentor commentor){
		
		logger.info("In Business Object Class- addCommentor Method:");
		commentorDAO.addCommentor(commentor);
	}
 
	//call DAO to return commentor
	public List<Commentor> listCommentor(){
		logger.info("In Business Object Class- listCommentor Method:");
		return commentorDAO.listCommentor();
	}
}

CommentorDAOImpl(DAO class implementing CommentorDAO interface)

package com.ankit.dao;

import java.util.List;

import org.apache.log4j.Logger;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

import com.ankit.controller.LoginServlet;
import com.ankit.dao.CommentorDAO;
import com.ankit.model.Commentor;
 
public class CommentorDAOImpl extends HibernateDaoSupport 
    implements CommentorDAO{
	Logger logger = Logger.getLogger(CommentorDAOImpl.class);
	//add commentor
	public void addCommentor(Commentor commentor){
		
		logger.info("In DAO Class- addCommentor Method:");
		getHibernateTemplate().save(commentor);
	}
 
	//return all the cummentors in list
	public List<Commentor> listCommentor(){
		
		logger.info("In DAO Class- listCommentor Method:");
		return getHibernateTemplate().find("from Commentor");		
	}
 
}

Commentor.hbm.xml(Hibernate mapping file)

<?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <!-- Generated 25 Apr, 2014 11:44:57 AM by Hibernate Tools 3.4.0.CR1 --> <hibernate-mapping> <class name="com.ankit.model.Commentor" table="commentor" catalog="login"> <id name="commentorId" type="java.lang.Long"> <column name="COMMENTOR_ID"/> <generator class="identity"/> </id> <property name="name" type="java.lang.String"> <column name="NAME" length="45"/> </property> <property name="comment" type="java.lang.String"> <column name="COMMENT" length="255" /> </property> <property name="createdDate" type="timestamp"> <column name="CREATED_DATE" length="19" /> </property> </class> </hibernate-mapping>

commentor.jsp(Struts view page(same page is being returned on either adding or listing the commentors))

<%@ page import ="org.apache.log4j.*" %>
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
</head>
 
<body>
<h1>Commentors Page</h1>
 
<h2>Add Comments</h2>

<%Logger logger = Logger.getLogger("commentor.jsp");
logger.info("in Commentor JSP");
%>
<s:form action="addCommentorAction" >
  <s:textfield name="name" label="Name" value="" />
  <s:textarea name="comment" label="Your Comment" value="" cols="50" rows="5" />
  <s:submit />
</s:form>
 
<h2>All Commentors</h2>

   <s:if test="commentorList.size()>0"> 
<table border="1px" >
 	<tr>
 		<th>Commentor Id</th>
 		<th>Name</th>
 		<th>Comment</th>
 		<th>Created Date</th>
 	</tr>
 	
 	 <s:iterator value="commentorList" status="userStatus">
 		<tr>
 			<td><s:property value="commentorId" /></td>
 			<td><s:property value="name" /></td>
 			<td><s:property value="comment" /></td>
 			<td><s:date name="createdDate" format="dd/MM/yyyy" /></td>
 		</tr>
  </s:iterator>  	
 </table>
   </s:if>  
<br/>
<br/>
 
</body>
</html>

attached below(first screen-shot) is screen-shot when I am trying to access the application first time(without adding a commentor).

second screen-shot is of page which used to appear after you have entered details and hit submit button.It can be seen that action url has been changed(from listCommentor.action to addCommentor.action).

But I am not able to see the list of commentors which are already been added.

I can see that arraylist is not empty from logs and can confirm that details are being inserted in database properly but not able to display over JSP(commentor.jsp)

Could you please give me an idea..

Also please let me know in case I would have to add other config files(struts,spring) to problem posted.

[Joe Ess]

Are these methods being invoked? The name should be in Camel Case (i.e. getCommentorList() )

    public List<Commentor> getcommentorList() {  
...
    public void setcommentorList(List<Commentor>commentorList) {  

[Ankit Tripathi]

Thanks for your response..

Do I have to define these setter and getter for list in my entity class?

[Joe Ess]

Your entity class is Commentor, right? Why would you declare a getter for a list of Commentor in Commentor?

[Ankit Tripathi]

I can see in logs that these methods are not being invoked in my action class(CommentorAction.java)..

public List<Commentor> getcommentorList() {  
          
        logger.info("In Entity Class- commentorList-getter method:");  
        return commentorList;  
    }  
   
    public void setcommentorList(List<Commentor>commentorList) {  
        this.commentorList = commentorList;  
          
        logger.info("In Action Class- commentorList-setter method: "+this.commentorList);  
    }  

Apart from above I can sniff that commentorList.size() is throwing a null pointer exception while execution of commentor.jsp:

2014-06-11 19:59:27,744 [ACTIVE] ExecuteThread: '12' for queue: 'weblogic.kernel.Default (self-tuning)' DEBUG ognl.OgnlValueStack - Caught an exception while evaluating expression 'commentorList.size()>0' against value stack
java.lang.NullPointerException: target is null for method size
at ognl.OgnlRuntime.callMethod(OgnlRuntime.java:1367)
at ognl.ASTMethod.getValueBody(ASTMethod.java:90)
at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212)
at ognl.SimpleNode.getValue(SimpleNode.java:258)
at ognl.ASTChain.getValueBody(ASTChain.java:141)
at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212)
at ognl.SimpleNode.getValue(SimpleNode.java:258)
at ognl.ASTGreater.getValueBody(ASTGreater.java:50)
at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212)
at ognl.SimpleNode.getValue(SimpleNode.java:258)
at ognl.Ognl.getValue(Ognl.java:494)
at com.opensymphony.xwork2.ognl.OgnlUtil.getValue(OgnlUtil.java:255)
at com.opensymphony.xwork2.ognl.OgnlValueStack.getValue(OgnlValueStack.java:358)
at com.opensymphony.xwork2.ognl.OgnlValueStack.tryFindValue(OgnlValueStack.java:347)
at com.opensymphony.xwork2.ognl.OgnlValueStack.tryFindValueWhenExpressionIsNotNull(OgnlValueStack.java:322)
at com.opensymphony.xwork2.ognl.OgnlValueStack.findValue(OgnlValueStack.java:308)
at org.apache.struts2.components.Component.findValue(Component.java:357)
at org.apache.struts2.components.If.start(If.java:86)
at org.apache.struts2.views.jsp.ComponentTagSupport.doStartTag(ComponentTagSupport.java:53)
at jsp_servlet.__commentor._jsp__tag4(__commentor.java:307)
at jsp_servlet.__commentor._jspService(__commentor.java:112)

[Joe Ess]

As I said in my previous post, your method names should be in Camel Case. I even provided you with what the method name should be.
Struts uses reflection to discover properties at run time. If you don't follow the JavaBeans Specification standards on accessor naming, Struts will not be able to find your properties.

[Ankit Tripathi]

Hi Joe,

I got it working finally.... ...thanks
But with one glitch ....when I am refreshing the page and even if there is no record in database,automatically last inserted row is displayed..not sure why?
and why I haven't got any error when my setters/getters were not in camel case.
Thanks for your help so far

[Joe Ess]

Ankit Tripathi wrote:
when I am refreshing the page and even if there is no record in database,automatically last inserted row is displayed..not sure why?

How is it displaying the "last inserted row" if "there is no record in database"?
When you "refresh" the page, you are making a request to the server. That executes an action...

Ankit Tripathi wrote:
why I haven't got any error when my setters/getters were not in camel case.

Struts eats a lot of errors that some think would give better feedback to a developer: see this article
Make sure you turn on devmode so you get all the feedback that Struts can give (and make sure you turn it off in production!)