In JSF, <h:selectManyListbox /> tag is used to render a multiple select listbox – HTML select element with “multiple” and “size” attribute.
//JSF...
<h:selectManyListbox value="#{user.favFood1}">
<f:selectItem itemValue="Fry Checken" itemLabel="Food1 - Fry Checken" />
<f:selectItem itemValue="Tomyam Soup" itemLabel="Food1 - Tomyam Soup" />
<f:selectItem itemValue="Mixed Rice" itemLabel="Food1 - Mixed Rice" />
</h:selectManyListbox>
//HTML output...
<select name="j_idt6:j_idt8" multiple="multiple" size="3">
<option value="Fry Checken">Food1 - Fry Checken</option>
<option value="Tomyam Soup">Food1 - Tomyam Soup</option>
<option value="Mixed Rice">Food1 - Mixed Rice</option>
</select>
h:selectManyListbox example
A JSF 2.0 example to show the use of “h:selectManyListbox” tag to render multiple select listbox, and populate the data in 3 different ways :
- Hardcoded value in “
f:selectItem” tag. - Generate values with a
Mapand put it into “f:selectItems” tag. - Generate values with an
Objectarray and put it into “f:selectItems” tag, then represent the value with “var” attribute.
1. Backing Bean
A backing bean to hold and generate data for the multiple select listbox values. The property to hold the multi-selected listbox value, must be a type of Collection or Array; Otherwise it will hits the following error message
WARNING: Target model Type is no a Collection or Array
javax.faces.FacesException: Target model Type is no a Collection or Array
package com.mkyong;
import java.io.Serializable;
import java.util.Arrays;
import java.util.LinkedHashMap;
import java.util.Map;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;
@ManagedBean(name="user")
@SessionScoped
public class UserBean implements Serializable{
public String[] favFood1;
public String[] favFood2;
public String[] favFood3;
//getter and setter methods...
public String getFavFood1InString() {
return Arrays.toString(favFood1);
}
public String getFavFood2InString() {
return Arrays.toString(favFood2);
}
public String getFavFood3InString() {
return Arrays.toString(favFood3);
}
//Generated by Map
private static Map<String,Object> food2Value;
static{
food2Value = new LinkedHashMap<String,Object>();
food2Value.put("Food2 - Fry Checken", "Fry Checken"); //label, value
food2Value.put("Food2 - Tomyam Soup", "Tomyam Soup");
food2Value.put("Food2 - Mixed Rice", "Mixed Rice");
}
public Map<String,Object> getFavFood2Value() {
return food2Value;
}
//Generated by Object array
public static class Food{
public String foodLabel;
public String foodValue;
public Food(String foodLabel, String foodValue){
this.foodLabel = foodLabel;
this.foodValue = foodValue;
}
public String getFoodLabel(){
return foodLabel;
}
public String getFoodValue(){
return foodValue;
}
}
public Food[] food3List;
public Food[] getFavFood3Value() {
food3List = new Food[3];
food3List[0] = new Food("Food3 - Fry Checken", "Fry Checken");
food3List[1] = new Food("Food3 - Tomyam Soup", "Tomyam Soup");
food3List[2] = new Food("Food3 - Mixed Rice", "Mixed Rice");
return food3List;
}
}
2. JSF Page
A JSF page to demonstrate the use “h:selectManyListbox” tag.
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
>
<h:body>
<h1>JSF 2 multi-select listbox example</h1>
<h:form>
1. Hard-coded with "f:selectItem" :
<h:selectManyListbox value="#{user.favFood1}">
<f:selectItem itemValue="Fry Checken" itemLabel="Food1 - Fry Checken" />
<f:selectItem itemValue="Tomyam Soup" itemLabel="Food1 - Tomyam Soup" />
<f:selectItem itemValue="Mixed Rice" itemLabel="Food1 - Mixed Rice" />
</h:selectManyListbox>
<br /><br />
2. Generated by Map :
<h:selectManyListbox value="#{user.favFood2}">
<f:selectItems value="#{user.favFood2Value}" />
</h:selectManyListbox>
<br /><br />
3. Generated by Object array and iterate with var :
<h:selectManyListbox value="#{user.favFood3}">
<f:selectItems value="#{user.favFood3Value}" var="f"
itemLabel="#{f.foodLabel}" itemValue="#{f.foodValue}" />
</h:selectManyListbox>
<br /><br />
<h:commandButton value="Submit" action="result" />
<h:commandButton value="Reset" type="reset" />
</h:form>
</h:body>
</html>
result.xhtml…
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://java.sun.com/jsf/html"
>
<h:body>
<h1>JSF 2 multi-select listbox example</h1>
<h2>result.xhtml</h2>
<ol>
<li>user.favFood1 : #{user.favFood1InString}</li>
<li>user.favFood2 : #{user.favFood2InString}</li>
<li>user.favFood3 : #{user.favFood3InString}</li>
</ol>
</h:body>
</html>
3. Demo
When “submit” button is clicked, link to “result.xhtml” page and display the submitted multi-selected listbox values.
How to pre-select multiple listbox values ?
The value of “f:selectItems” tag is selected if it matched to the “value” of “h:selectManyListbox” tag. In above example, if you set favFood1 property to “Fry Checken” and “Tomyam Soup” :
@ManagedBean(name="user")
@SessionScoped
public class UserBean{
public String[] favFood1 = {"Fry Checken", "Tomyam Soup"};
//...
The “favFood1″ listbox values, “Fry Checken” and “Tomyam Soup” are selected by default.