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Struts

Problem reg. Delete Operation in my struts application

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posted 15 years ago

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Hi All,
I'm creating a strut application. In this User will click Sign In Link and will enter username/password and after that will be anle to see all the records from database along with Delete link at the end of each records.

But when I click record that record is not deleted. I found that the function in which delete query is mentioned is not being called at all But i am not able to find what is the problem / going wrong. I am not getting any error / Exception. But page goes blank when i click Delete link at end of a record.

Below is the codes.

struts-config.xml
============

<struts-config>
       
    <form-beans>
        <form-bean name="logonForm" type="app.LogonForm"/>
    </form-beans>
    
    <global-exceptions>
    
    </global-exceptions>

<global-forwards>
        <forward name="welcome"  path="/Welcome.do"/>
        <forward name="logon"  path="/logon.jsp"/>
    </global-forwards>

<action-mappings>
        
        <action path="/LogonSubmit" name="logonForm" type="app.UserListAction" scope="request" input="/logon.jsp" validate="true">
            
            
            <forward name="success" path="/userList.do"/>
        </action>
        
        <action path="/Delete" type="app.DeleteUserAction" scope="request" validate="false">
            <forward name="success" path="/userlist.jsp"/>
        </action>
        
        <action path="/userList" type="app.UserListAction" scope="request">
            <forward name="success" path="/userlist.jsp"/>
        </action>
            
        <action path="/Welcome" forward="/welcomeStruts.jsp"/>
    </action-mappings>   
      
    
</struts-config>

userlist.jsp (This is the JSP for displaying the records).
===================================

<%@ taglib  uri="/WEB-INF/struts-html.tld" prefix="html" %>
<%@ taglib uri="/WEB-INF/struts-logic.tld" prefix="logic"%>
<%@ taglib uri="/WEB-INF/struts-bean.tld" prefix="bean" %>

<body>
        <html:errors/>
        <h2><font face="VERDANA"><center><bean:message key="logon.userlist"/></center></font></h2>
        <hr>
        <center>
            <table  border="0"  >
                 <tr >
                     <th><bean:message key="logon.username"/></th>
                     <th><bean:message key="logon.password"/></th>
                 </tr>
                 
 
                 <logic:iterate id="user" name="users">
                     <tr >
                         <td>
                             <bean:write name="user" property="username"/>
                         </td>
                         <td>
                             <bean:write name="user" property="password"/>
                         </td>
                         <td>
                             <a user" / rel="nofollow">">Delete</a>
                         </td>
                     </tr>
                 </logic:iterate>
             </table>
        </center>
    </body>
</html>

removeUser Function from LogonData Class
=============================

public static void removeUser(String username) throws Exception{
        System.out.println("\n In the removeUser Function");
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        
        try{
            Class.forName("com.mysql.jdbc.Driver").newInstance();
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/logon", "root", "");
            stmt = conn.createStatement();
            
            //StringBuffer sqlString = new StringBuffer("delete from user_login_detail where username='" + username + "'");
            System.out.println("\nBefore Deleting User");
            boolean flgstatus = stmt.execute("delete from user_login_detail where username='" + username + "'");
            System.out.println("\nAfter Deleting User");
            //stmt.execute(sqlString.toString());
        }finally{
            if(rs != null){
                rs.close();
            }
            if(stmt != null){
                stmt.close();
            }
            if(conn != null){
                conn.close();
            }
        }
    }

DeleteUserAction.java
===============

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package app;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionError;

/**
 *
 * @author Jay Shukla
 */
public class DeleteUserAction extends Action{
    public ActionForward execute(ActionForm form, ActionMapping mapping, 
            HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException{
        System.out.println("\nIn the DeleteUserAction Class");
        String target = new String("success");
        
        try{
            LogonData.removeUser(request.getParameter("username"));            
        }catch(Exception e){
            System.err.println("Setting target to error");
            target = new String("error");
            
            ActionErrors errors = new ActionErrors();
            errors.add(ActionErrors.GLOBAL_ERROR, new ActionError("errors.database.error", e.getMessage()));
            
            if(!errors.isEmpty()){
                saveErrors(request, errors);
            }            
        }
        return (mapping.findForward(target));
    }
}

Please help me resolving problem related to delete function.

Thanks in Advance.

David Newton

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Posts: 12617

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posted 15 years ago

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I have several concerns about this code, including SQL injection and web crawlers.

That aside, it appears as though the HTML you posted was partially messed up.

If nothing else, you should set logging to DEBUG level and check the logs for any exceptions--I'd imagine there's one there.

Also, try to take care to keep your code clean--there's no reason to try to close a result set that will never be not null. Commented-out code just obfuscates the real code and makes it more difficult for us (and you) to see what's going on. There's no need to ever call new String("foo")--just use an immediate string. You don't need to check to see if errors is empty immediately after adding an error.

Clean code counts--and it makes tracking down issues much, much easier.

Jay Shukla

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Posts: 214

posted 15 years ago

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Hi David,

Thanks for reply and valuable suggestions. Actually i'm new to struts and following professional Jakarta Struts Books.

Anyway, Here is the userlist.jsp

<%@ taglib  uri="/WEB-INF/struts-html.tld" prefix="html" %>
<%@ taglib uri="/WEB-INF/struts-logic.tld" prefix="logic"%>
<%@ taglib uri="/WEB-INF/struts-bean.tld" prefix="bean" %>

Thanks in Advance.

Jay Shukla

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Posts: 214

posted 15 years ago

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It seems thereis a problem in the code that prints Delete link in the JSP. Hence i'm putting that snippet below.

Below is the small snippet from userlist.jsp

<logic:iterate id="user" name="users">
<tr >
<td>
<bean:write name="user" property="username"/>
</td>
<td>
<bean:write name="user" property="password"/>
</td>
<td>
">Delete
</td>
</tr>
</logic:iterate>

Thanks.

David Newton

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posted 15 years ago

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You need to both disable HTML and use code tags:There's a "Preview" button to allow you to see if your posts are rendering correctly.

Jay Shukla

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posted 15 years ago

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Thanks David for this valuable suggestion
Here is the snippet.
What is going wrong in the code?. How to resolve problem?

Thanks in Advance.

David Newton

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posted 15 years ago

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What were the results of the increased debug logging?

Jay Shukla

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posted 15 years ago

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Hi David,

Could you let me know any reference regarding how to set / increase DEBUG level for this application.

Thanks in Advance.

David Newton

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posted 15 years ago

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Depends on what logging package you're using, but it starts with setting devMode to true for some basic info.

I use Log4J, so I use either a Log4J properties or XML config file to set up Struts 2 and/or XWork and/or OGNL to log at DEBUG level, depending on the nature of what I'm trying to track down.

David Newton

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Oops, you're using Struts 1. The Log4J stuff applies anyway, as far as I can recall.

Jay Shukla

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posted 15 years ago

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Hi David ,

Thanks for reply. Currently i'm not using log4j package to my struts application. So is it fine if i define DEBUG level in web.xml as an init parameter?

Thanks.

David Newton

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I have no idea; if that will configure commons-logging, sure.

Jay Shukla

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posted 15 years ago

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Hi,

Sorry for late reply.
I tried defining DEBUG level in web.xml but seems that its giving the same log.

Is there another way that can be configured?Even if i use log4j package where do i need to print the logging statements that will help to resolve this issue.

Can some one please help me on above.

Thanks in Advance.

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