Results 1 to 4 of 4
  1. #1
    jellyfish888 is offline Member
    Join Date
    Dec 2007
    Posts
    7
    Rep Power
    0

    Default I need help with my java servlet homework(add,edit and delete)

    I have a homework in which our teacher asked us to write a code in which the user can add, delete and edit his wishlist...I can only do add and delete...I am sure that there is a lot of problem for edit so please help me to make it work...I am using database for this...

    This is my html code:
    Java Code:
    <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
    <title>Christmas Wishes</title>
    </head>
    <body>
    <h3>Place Your Christmas Wishes Here</h3>
    <form action="ChristmasWishlist" method=post>
    <table>
    <tr><th>Wish:</th><td><input type=text name=gift size=100></td></tr>
    <tr><th>Amount:</th><td><input type=text name=amount size=10></td></tr>
    <tr><th colspan=2><input type=submit name=submit value="Add"></th></tr>
    </table>
    </form>
    </body>
    </html>
    This is my servlet:
    Java Code:
    import java.sql.Connection;
    import java.sql.DriverManager;
    
    public class ConnectionManager {
    
    	protected Connection con;
        protected String driver = "com.mysql.jdbc.Driver";
        String url = "jdbc:mysql://localhost:3306/";
        String database = "WishList";
        String user = "root";
        String password = "";
        
        /** Creates a new instance of ConnectionManager */
        public ConnectionManager() {
            
        }
        public Connection logOn(){
            try {
    		Class.forName(driver).newInstance();
    		con = DriverManager.getConnection(url+database,user,password);
    		
            }
            catch(Exception e){
                System.out.print(e.getMessage());
            }
            return con;
            
        }
        
        public void logOff(){
            try {
                con.close();
            }
             catch(Exception e){
                e.printStackTrace();
            }
        }
    }
    This is my other servlet:
    Java Code:
    import java.io.IOException;
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.sql.*;
    
    /**
     * Servlet implementation class for Servlet: ChristmasWishlist
     * 
     */
    public class ChristmasWishlist extends javax.servlet.http.HttpServlet implements
    		javax.servlet.Servlet
    {
    	static final long serialVersionUID = 1L;
    
    	/*
    	 * Connect to the database
    	 */
    
    	/*
    	 * (non-Java-doc)
    	 * 
    	 * @see javax.servlet.http.HttpServlet#HttpServlet()
    	 */
    	public ChristmasWishlist()
    	{
    		super();
    	}
    
    	/*
    	 * (non-Java-doc)
    	 * 
    	 * @see javax.servlet.http.HttpServlet#doGet(HttpServletRequest request,
    	 *      HttpServletResponse response)
    	 */
    	protected void doGet(HttpServletRequest request,
    			HttpServletResponse response) throws ServletException, IOException
    	{
    		// TODO Auto-generated method stub
    		process(request, response);
    	}
    
    	/*
    	 * (non-Java-doc)
    	 * 
    	 * @see javax.servlet.http.HttpServlet#doPost(HttpServletRequest request,
    	 *      HttpServletResponse response)
    	 */
    	protected void doPost(HttpServletRequest request,
    			HttpServletResponse response) throws ServletException, IOException
    	{
    		// TODO Auto-generated method stub
    		process(request, response);
    	}
    
    	protected void process(HttpServletRequest request,
    			HttpServletResponse response) throws ServletException, IOException
    	{
    		response.setContentType("text/html");
    		java.io.PrintWriter out = response.getWriter();
    		out.println("<html><title>List of All Your Wishes</title><body>");
    
    		//check if you are getting the right values, comment out once the program is working
    		//line below will work only for java 5 up
    		java.util.Enumeration e = request.getParameterNames();
    		while (e.hasMoreElements())
    		{
    			String gift = e.nextElement().toString();
    			out.println("<br>" + gift + " - " + request.getParameter(gift));
    		}
    
    		if (request.getParameter("submit") != null)
    		{
    			if (!request.getParameter("submit").isEmpty())
    			{
    				if (request.getParameter("submit").equals("Add"))
    				{
    					if (!request.getParameter("gift").isEmpty())
    					{
    						out.println(addChristmasWishlist(request
    								.getParameter("gift")));
    					} 
    					else
    					{
    						out.println("<p>Nothing to do");
    					}
    				}
    				
    				else if(request.getParameter("submit").equals("Delete"))
    				{
    					delChristmasWishlist(Integer.parseInt(request.getParameter("id")));
    				}
    			else if(request.getParameter("submit").equals("Delete"))
    			{
    				out.println("<p>Nothing to do");
    			}
    		}
    
    		} else
    		{
    			out.println("<p>empty");
    		}
    		out.println("<p><a href=wish.html>Add again</a>");
    		
    		ResultSet rst = null;
    		try
    		{
    			rst = viewChristmasWishlist();
    			int count = 1;
    			out.println("<table><tr><th colspan=2>ChristmasWishlist</th></tr>");
    			while(rst.next())
    			{
    				out.println("<tr><td><b>"+count+".</b></td><td>"+rst.getString("gift")+"</td>" + 
    						"<td><a href=ChristmasWishlist?id="+rst.getInt("id")+"&submit=Edit>Edit</a.</td>"+
    						"<td><a href=ChristmasWishlist?id="+rst.getInt("id")+"&submit=Delete>Delete</a.</td></tr>");
    				count++;
    			}
    			out.println("</table>");
    		}
    		catch(Exception e2)
    		{
    			
    		}
    		
    		out.println("</body></html>");
    
    	}
    
    	public String addChristmasWishlist(String wish)
    	{
    
    		try
    		{
    			ConnectionManager con = new ConnectionManager();
    			Statement stmt = con.logOn().createStatement();
    			String msg = "";
    			String sql = "insert into wishes set gift='" + wish.replaceAll("\'", "\\\'") + "'";
    			if (stmt.execute(sql))
    			{
    				msg = "Insert failed";
    			} 
    			else
    			{
    				msg =  "Added successfully";
    			}
    			con.logOff();
    			return msg;
    			
    		} 
    		catch (SQLException e)
    		{
    			
    			return "Add failed. SQL error " + e.getMessage();
    		} 
    		catch (java.lang.NullPointerException ne)
    		{
    			
    			return "<?p>Null error: " + ne.getMessage();
    		}
    
    	}
    	
    	
    	public String delChristmasWishlist(int id)
    	{
    
    		try
    		{
    			ConnectionManager con = new ConnectionManager();
    			Statement stmt = con.logOn().createStatement();
    			String msg = "";
    			String sql = "delete from wishes where id="+id;
    			if (stmt.execute(sql))
    			{
    				msg = "Delete failed";
    			} else
    			{
    				msg =  "Delete successfully";
    			}
    			con.logOff();
    			return msg;
    			
    		} catch (SQLException e)
    		{
    			
    			return "Add failed. SQL error " + e.getMessage();
    		} catch (java.lang.NullPointerException ne)
    		{
    			
    			return "<p>Null error: " + ne.getMessage();
    		}
    		
    		
    
    	}
    
    	public String editChristmasWishlist(String wish)
    	{
    
    		try
    		{
    			ConnectionManager con = new ConnectionManager();
    			Statement stmt = con.logOn().createStatement();
    			String msg = "";
    			String sql = "update from wishes where gift="+wish;
    			if (stmt.execute(sql))
    			{
    				msg = "update failed";
    			} else
    			{
    				msg =  "update successfully";
    			}
    			con.logOff();
    			return msg;
    			
    		} catch (SQLException e)
    		{
    			
    			return "Add failed. SQL error " + e.getMessage();
    		} catch (java.lang.NullPointerException ne)
    		{
    			
    			return "<p>Null error: " + ne.getMessage();
    		}
    		
    		
    
    	}
    
    	public ResultSet viewChristmasWishlist()
    	{
    
    		ResultSet rst = null;
    		try
    		{
    			ConnectionManager con = new ConnectionManager();
    			Statement stmt = con.logOn().createStatement();
    			String msg = "";
    			
    			String sql = "select * from  wishes";
    			rst = stmt.executeQuery(sql);
    	
    			
    		} catch (SQLException e)
    		{
    			
    			
    		} catch (java.lang.NullPointerException ne)
    		{
    			
    			
    		}
    		return rst;
    	}
    
    }

  2. #2
    jellyfish888 is offline Member
    Join Date
    Dec 2007
    Posts
    7
    Rep Power
    0

    Default

    please help me with this...you can just concentrate on edit since I was able to do add and delete...please and thank you...

  3. #3
    jellyfish888 is offline Member
    Join Date
    Dec 2007
    Posts
    7
    Rep Power
    0

    Default This is the dit part which I think have a lot of problem...

    Java Code:
    public String editChristmasWishlist(String wish)
    	{
    
    		try
    		{
    			ConnectionManager con = new ConnectionManager();
    			Statement stmt = con.logOn().createStatement();
    			String msg = "";
    			String sql = "update from wishes where gift="+wish;
    			if (stmt.execute(sql))
    			{
    				msg = "update failed";
    			} else
    			{
    				msg =  "update successfully";
    			}
    			con.logOff();
    			return msg;
    			
    		} catch (SQLException e)
    		{
    			
    			return "Add failed. SQL error " + e.getMessage();
    		} catch (java.lang.NullPointerException ne)
    		{
    			
    			return "<p>Null error: " + ne.getMessage();
    		}
    		
    		
    
    	}

    Please help me make this code work...

  4. #4
    wsaryada is offline Senior Member
    Join Date
    Jun 2007
    Location
    Bali, Indonesia
    Posts
    762
    Rep Power
    10

    Default

    What is the actual problem you get from your code? can you tell us?

    What I am guessing right now is could be you are missing a quote in your sql update command. Shouldn't it be something like:

    Java Code:
    "update from wishes where gift='" + wish + "'";

Similar Threads

  1. Can I delete/uninstall older versions of Java?
    By LudwigKarl in forum New To Java
    Replies: 3
    Last Post: 03-19-2008, 11:23 AM
  2. I need help with my java servlet homework(average)
    By jellyfish888 in forum Java Servlet
    Replies: 2
    Last Post: 12-23-2007, 10:57 PM
  3. Help with my java servlet homework
    By jellyfish888 in forum Java Servlet
    Replies: 2
    Last Post: 12-21-2007, 06:41 PM
  4. how to edit lines.
    By jason27131 in forum New To Java
    Replies: 1
    Last Post: 08-01-2007, 04:41 AM
  5. Doubt in edit and delete methods
    By ai_2007 in forum Advanced Java
    Replies: 3
    Last Post: 07-01-2007, 11:40 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •