returning an int

[Roberto Favaro]

This is a problem im having.Im trying to enter an id in HTML and return its details.I cant seem to compile my code correctly but I cant see how I can fiv it .Im lost

My bussiness class

//Product.java
 
package cp3039proj.business ;
 
public class Product
{
private int id;
private String name;
private double price;
 
public Product()
{
id = 0;
name = "";
price = 0.00;
}
 
public Product(int id,String name,double price)
{
this.id = id;
this.name = name;
this.price = price;
}
 
public int getId()
{
return id;
}
 
public String getName()
{
return name;
}
 
public double getPrice()
{
return price;
}
 
public void setId(int id)
{
this.id = id;
}
 
public void setName(String name)
{
this.name = name;
}
 
public void setPrice(double price)
{
this.price = price;
}
}  

my Product DAO class

//ProductDao.java
 
package cp3039proj.dao ;
 
import java.util.* ;
import java.sql.* ;
import java.io.* ;
 
import cp3039proj.business.* ;
import cp3039proj.broker.* ;
import cp3039proj.exceptions.* ;
 
public class ProductDao
{
MyBroker broker = null ;
 
public ProductDao() throws DaoException
{
broker = MyBroker.getInstance() ;
}
public Connection getConnection() throws DaoException
{
String driver = null ;
String url = null ;
String username = null ;
String password = null ;
Connection con = null ;
 
Properties props = new Properties() ;
try
{
FileInputStream in = new FileInputStream("/cp3039log/project.properties") ;
props.load(in) ;
driver = props.getProperty("jdbc.driver") ;
url = props.getProperty("jdbc.url") ;
username = props.getProperty("jdbc.username") ;
password = props.getProperty("jdbc.password") ;
 
Class.forName(driver) ;
con = DriverManager.getConnection(url, username, password) ;
}
catch(IOException ioe)
{
System.out.println("Failed to find properties file: " + ioe.getMessage() ) ;
System.exit(1) ;
}
catch(ClassNotFoundException cnfe)
{
System.out.println("Failed to find driver: " + cnfe.getMessage() ) ;
System.exit(1) ;
}
catch(SQLException sqle)
{
throw new DaoException("Failed to connect to database: " + sqle.getMessage() ) ;
}
return con ;
}
public void freeConnection(Connection con) throws DaoException
{
if (con != null)
{
try
{
con.close() ;
con = null ;
}
catch(SQLException e)
{
throw new DaoException("freeConection(): " + e.getMessage() ) ;
}
}
}
 
public Product getProduct(int item) throws DaoException
{
Connection con = null ;
Statement stmt = null ;
ResultSet rs = null ;
Product p = null ;
try
{
con = getConnection() ;
stmt = con.createStatement() ;
String query = "SELECT * from Product WHERE id = " + item  ;
System.out.println(query) ;
rs = stmt.executeQuery(query) ;
 
if (rs.next() )
{
int id = rs.getInt("id") ;
String name = rs.getString("name") ;
double price = rs.getDouble("price") ;
p = new Product(id, name,price) ;
}
}
catch(SQLException e)
{
throw new DaoException("getProduct(): " + e.getMessage() ) ;
}
finally
{
try
{
if (rs != null)rs.close() ;
if (stmt != null)stmt.close() ;
if (con != null)freeConnection(con) ;
}
catch(SQLException e)
{
throw new DaoException("getProduct(): " + e.getMessage() ) ;
}
}
 
return p ;
}
 
public ArrayList getProducts() throws DaoException
{
Connection con = null ;
Statement stmt = null ;
ResultSet rs = null ;
ArrayList a = new ArrayList() ;
 
try
{
con = getConnection() ;
stmt = con.createStatement() ;
String query = "SELECT * from Product" ;
System.out.println(query) ;
rs = stmt.executeQuery(query) ;
 
while (rs.next() )
{
int id = rs.getInt("id") ;
String name = rs.getString("name") ;
double price = rs.getDouble("price") ;
Product p = new Product(id, name,price) ;
a.add(p) ;
}
}
catch(SQLException e)
{
throw new DaoException("getProducts(): " + e.getMessage() ) ;
}
finally
{
try
{
if (rs != null)rs.close() ;
if (stmt != null)stmt.close() ;
if (con != null)freeConnection(con) ;
}
catch(SQLException e)
{
throw new DaoException("getProducts():" + e.getMessage()) ;
}
}
return a ;
}
 
public int addProduct(Product p) throws DaoException
{
Connection con = null ;
Statement stmt = null ;
int rows = 0 ;
try
{
con = getConnection() ;
stmt = con.createStatement() ;
String command = "INSERT INTO Product VALUES("
+p.getId() + ", '" + p.getName() + "'"
    + ", " + p.getPrice() + ")" ;
 
System.out.println(command) ;
rows = stmt.executeUpdate(command) ;
}
catch(SQLException e)
{
throw new DaoException("addProduct(): " + e.getMessage() ) ;
}
finally
{
try
{
if (stmt != null)
stmt.close() ;
if (con != null)
freeConnection(con) ;
}
catch(SQLException e)
{
throw new DaoException("addProduct():" + e.getMessage() ) ;
}
}
 
return rows;
}
 
public int deleteProduct(int item) throws SQLException
{
Connection con = null;
Statement stmt = null;
int rows = 0;
try
{
con = getConnection();
stmt = con.createStatement();
String command = "DELETE FROM Product WHERE id = " + item ;
System.out.println(command);
rows = stmt.executeUpdate(command);
}
catch(SQLException e)
{
throw new DaoException("deleteProduct(): " + e.getMessage() );
}
finally
{
try
{
if (stmt != null)
stmt.close() ;
if (con !=null)
freeConnection(con);
}
catch(SQLException e)
{
throw new DaoException("deleteProduct(): " + e.getMessage() );
}
}
 
//System.out.println(rows);
return rows;
}
 
public int amendProduct(int id, String name, double price) throws DaoException
{
Connection con = null;
Statement stmt = null;
int rows = 0;
try
{
con = getConnection();
stmt = con.createStatement();
String command = "UPDATE Product SET name = '"
+ name + "', price = " + price
+ " WHERE id = " + id ;
System.out.println(command);
rows = stmt.executeUpdate(command);
}
 
catch(SQLException e)
{
throw new DaoException("amendProduct(): " + e.getMessage() );
}
 
finally
{
try
{
if (stmt != null)
stmt.close() ;
if (con !=null)
freeConnection(con);
}
 
catch(SQLException e)
{
throw new DaoException("amendProduct(): " + e.getMessage() );
}
}
 
//System.out.println(rows);
return rows;
}
/*
public static void main(String[] args)
{
int item ;
int rows ;
Product p = null ;
MyBroker broker = null ;
ProductDao dao = null ;
try
{
broker = MyBroker.getInstance() ;
dao = new ProductDao() ;
System.out.println("getProduct(\"3\")") ;
p = dao.getProduct(3) ;
if (p != null)
{
System.out.println("ProductId: " + p.getId()
+ " name: " + p.getName()
+ " price: " + p.getPrice() ) ;
}
else
{
System.out.println("No such product") ;
}
 
System.out.println("getProducts") ;
ArrayList a = dao.getProducts() ;
for (int i = 0 ; i < a.size() ; i++)
{
p = (Product) a.get(i) ;
System.out.println("ProductId: " + p.getId()
+ " name: " + p.getName()
+ " price: " + p.getPrice() ) ;
}
 
System.out.println("addProduct") ;
p = new Product (16, "Portugal", 61.00) ;
rows = dao.addProduct(p);
 
System.out.println("deleteProduct");
rows = dao.deleteProduct(16);
 
System.out.println("amendProduct");
rows = dao.amendProduct(2, "Spain", 61.00);
System.out.println("Rows Affected = " + rows);
}
catch(SQLException e)
{
System.out.println(e ) ;
}
 

finally
{
broker.destroy() ;
}
}*/
}
 
  

My business class *This wont compile correctly*

//GetProductCommand.java
 
package cp3039proj.command ;
 
import java.util.* ;
import java.sql.* ;
import java.io.* ;
import javax.servlet.* ;
import javax.servlet.http.* ;
 
import cp3039proj.business.* ;
import cp3039proj.dao.* ;
import cp3039proj.exceptions.* ;
 
public class GetProductCommand implements Command
{
public GetProductCommand()
{
}
public String execute(HttpServletRequest request, HttpServletResponse response)
{
String page = null ;
 
try
{
String productId = request.getParameter("ProductId") ;
if (productId == null || productId.length() == 0)
{
//id has not been submitted
page = "InputProductId.jsp" ;
}
else
{
// id has been submitted
 
ProductDao dao = new ProductDao() ;
Product product = dao.getProduct(productId) ;
if (product == null)
{
request.setAttribute("errorMessage", NO_SUCH_PRODUCT) ;
page = errorPage ;
}
else
{
request.setAttribute("product", product) ;
page = "Product.jsp" ;
}
}
 
}
catch(DaoException e)
{
page = errorPage ;
request.setAttribute("errorMessage", e.getMessage() ) ;
}
 
return page ;
}
 
}  

Any help would be greatly appreciated.Even if someone could point me in the right direction.Tnx

[Sonny Gill]

What's the error message, and which line does the compiler point to?

[Roberto Favaro]

Sorry....Its pointing to the line in GetProductCommand.java

Product product = dao.getProduct(productId) ;  

Heres the error

G:\cp3039proj\command\GetProductCommand.java:37: getProduct(int) in cp3039proj.dao.ProductDao cannot be applied to (java.lang.String)
Product product = dao.getProduct(productId) ;  

[Fisher Daniel]

Hi,
I see that you have casting problem.
It is because you want to pass String object into method with integer argument.

  
public class ProductDAO {
 
   public Product getProduct(int item) throws DAOException {
     // the rest of your code is here
   }
}
 
public class GetProductCommand implements Command {
   
   public String execute(HttpServletRequest request, HttpServletResponse response){
   String productId = request.getParameter("ProductId") ;
 
   ProductDao dao = new ProductDao() ;
   Product product = dao.getProduct(productId) ; // here is your problem
   }  
}
 

You can change with this one

  
Product product = dao.getProduct(Integer.parseInt(productId));

Correct me if I am wrong..
Hope this help

daniel

[Bear Bibeault]

Moving to Java in General (intermediate)