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Java homework please help! :(
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I coded a script, Currently I can add and delete items to the database but I cannot edit the data. Here's my 3 paged script :
Christmasswishlist.java
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;
}
Connectionmanager.java
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();
}
}
Wish.html
<!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>
Christmasswishlist.java
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;
}
Connectionmanager.java
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();
}
}
Wish.html
<!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>
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Join Date: Aug 2005
Posts: 5,264
Reputation: 
Solved Threads: 377
- No one is going to look at that without [code][/code] tags
- And you need to pinpoint a specific issue you are having, not just post your entire code
If anyone else wants to look...
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Connectionmanager.java
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Wish.html
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Last edited by iamthwee; Dec 19th, 2007 at 4:07 pm.
*Voted best profile in the world*
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Join Date: May 2006
Posts: 1,824
Reputation:
Solved Threads: 117
Are you being able to execute "update from wishes where gift=<giftid>" via command prompt ?
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