Forum:

fill selectOneMenu from database

Greenhorn

Posts: 18

posted 12 years ago

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Hi All,
Why my code doesn't work ? After code execution on JSP page

an error message appears:

An Error Occurred:
Cannot convert [javax.faces.model.SelectItem@61d27a] of type class java.util.ArrayList to class javax.faces.model.SelectItem

Page: test.jsp

<html>

<%@ taglib uri="http://java.sun.com/jsf/core" prefix="f" %>
<%@ taglib uri="http://java.sun.com/jsf/html" prefix="h" %>

<f:view>
<head>

<title>

</title>
</head>
<body>
<h:form >

<h:selectOneMenu value=" # {Monbean.maValeur}" >
<f:selectItem value="#{Monbean .mesElements}"/>
</h:selectOneMenu>
</h:form>
</body>
</f:view>
</html>

Bean: Monbean.java

import java.sql.SQLException;

import java.util.ArrayList;

import java.util.List;

import javax.faces.model.SelectItem;

import java.sql.*;

import java.sql.DriverManager;

import java.util.logging.Level;

import java.util.logging.Logger;

public class Monbean {

private String maValeur;
Connection con ;
private List<SelectItem> mesElements;

public String getmaValeur() {
return maValeur;
}

public void setmaValeur(String maValeur) {
this.maValeur = maValeur;
}
private Iterable<String> getMaliste() throws SQLException {
ArrayList unelist = new ArrayList();

try
{
Class.forName("oracle.jdbc.driver.OracleDriver");
System.out.println ("driver etablie");
}
catch(Exception e)
{
System.out.println ("erreur:Driver int" +
"rouvable");
}

try

{
String URL = "jdbc:oracle:thin:@localhost:1521:gmao";

String USER = "pfe";
String PASSWD = "gmao";

con =DriverManager.getConnection(URL,USER, PASSWD);

System.out.println ("connexion base pfe etablie");
}
catch(Exception e)
{

System.out.println ("erreur: base introuvable");

}

Statement st = con.createStatement();

ResultSet resultats = null;

try {

resultats = st.executeQuery("select * from auteur");
}
catch (SQLException ex) {

Logger.getLogger(Monbean.class.getName()).log(Level.SEVERE, null, ex);
}

try {
while(resultats.next()){

String num=resultats.getString("nomaut").toString();

unelist.add(num);

}
}
//session.close();

catch (Exception e) {
e.printStackTrace();
}
return (List) unelist;
}

public List<SelectItem> getMesElements() throws SQLException {

if (mesElements == null) {

mesElements = new ArrayList<SelectItem>();

for (String val : getMaliste()) {

mesElements.add(new SelectItem(val));
}

}
return mesElements;

/** Creates a new instance of Monbean */

}

public Monbean() throws SQLException{

}
}

------------------------------

Could you please help me to correct my code

thank you

Krystian Gor

Ranch Hand

Posts: 30

posted 12 years ago

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I'm not sure but I think there's something wrong between getMaliste() and getMesElements().
Try to use this method:

and change
to

asmaa kellal

Greenhorn

Posts: 18

posted 12 years ago

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Hello
thanks for the answer
I still want to ask your help if possible when I select the menu item how I can insert it into another table son

I explain - idauteur (Menu) is a primary key in table 'author' (with which I completed) and a foreign key in table 'book'- how I can insert the selected value from the menu on the table' book '

Any advice would be greatly appreciated
thank you

Krystian Gor

Ranch Hand

Posts: 30

posted 12 years ago

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Do you have any working code to add 'author' and 'book' to database? Show me if you have. It will be easier to say if I can help you.
Also show me your 'author' class and 'book' class.

asmaa kellal

Greenhorn

Posts: 18

posted 12 years ago

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Here is the code to add 'author'

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

import java.sql.Connection;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;
import java.sql.*;
 import java.sql.DriverManager;

/**
 *
 * @author utilisateur
 */
@ManagedBean(name="InsertAction")
@SessionScoped
public class InsertAction {

private String idauteur;

Connection  con ;

String s=null;

public void setidauteur(String idauteur){
    this.idauteur=idauteur;
  }

public String getidauteur()
{
    return idauteur;
}

public String connexionBD() throws SQLException {
    String result=" ";

try
			    {
                     Class.forName("oracle.jdbc.driver.OracleDriver");
    			     System.out.println ("driver etablie");
			    }
			    catch(Exception e)
			    {
			    	System.out.println ("erreur:Driver int" +
			    			"rouvable");
			    }

try

{
			        String URL = "jdbc:oracle:thin:@localhost:1521:gmao";
			    	String USER = "pfe";
			    	String PASSWD = "gmao";

con =DriverManager.getConnection(URL,USER, PASSWD);
			    	System.out.println ("connexion  base pfe etablie");
			    }
			    catch(Exception e)
                                    {
System.out.println ("erreur: base introuvable");

}

Statement st = con.createStatement();

int val = 0;

try {
               
                 val= st.executeUpdate("insert into Author values('"+idauteur+"')")  ;
            } catch (SQLException ex) {
                Logger.getLogger(InsertAction.class.getName()).log(Level.SEVERE, null, ex);
            }

System.out.println(val);
return result;
}
/** Creates a new instance of InsertAction */

public InsertAction(){

}

Here is the code to add 'book' but missing the insertion of the selected item in the menu 'idauteur'

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

/**
 *
 * @author utilisateur
 */
@ManagedBean(name="InsertAction")
@SessionScoped
public class InsertAction {

private String idbook;

Connection  con ;

String s=null;

public void setidauteur(String idauteur){
    this.idauteur=idauteur;
  }

public String getidauteur()
{
    return idauteur;
}

public String connexionBD() throws SQLException {
    String result=" ";

try

{
			        String URL = "jdbc:oracle:thin:@localhost:1521:gmao";
			    	String USER = "pfe";
			    	String PASSWD = "gmao";

}

Statement st = con.createStatement();

int val = 0;

try {
               
                 val= st.executeUpdate("insert into book values('"+idbook+"')")  ;
            } catch (SQLException ex) {
                Logger.getLogger(InsertAction.class.getName()).log(Level.SEVERE, null, ex);
            }

System.out.println(val);
return result;
}
/** Creates a new instance of InsertAction */

public InsertAction(){

}

here are the two class

the class diagram are not many things to view
cardinalities between class UML '

author '1'---------------book '1...*'

what I need is how to insert an item selected by menu in the table book

Krystian Gor

Ranch Hand

Posts: 30

posted 12 years ago

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Using entity classes and accessing database with EntityManager would be more elegant and safer. Managing relations would be easier.
Strange usage of managed beans. I'm not familiar with what you're doing here.
Try reading some tutorials like this http://balusc.blogspot.com/2006/06/using-datatables.html

With a little knowledge, a cast iron skillet is non-stick and lasts a lifetime.