Thodoris Bais

About Thodoris Bais

Thodoris Bais is currently working as a Junior Java Developer while on parallel, pursuing a diploma at Informatics & Telecommunications Engineering. He specializes in Java Core, Android and J2EE and looks forward to being a professional Software Engineer. He is also a quick learner and curious about new technologies.

Dropdown List (selectOneMenu) Example with JSF 2.0

Hi there, it’s been a long time since my last example, but there isn’t any time at all, after work. So, let’s get back to business. Remembering myself explaining quite interesting stuff in an easy way, in the last few examples, we ‘ll continue on the same basis, but this time, we ‘ll get our hands dirty with dropdown lists!

In JSF, we can use the <h:selectOneMenu /> tag to render a dropdown list; an example could be like the following code snippet:
 
 
 
  

<h:selectOneMenu value="#{user.city}">
   	<f:selectItem itemValue="Kozani" itemLabel="City - Kozani" />
   	<f:selectItem itemValue="Kavala" itemLabel="City - Kavala" />
   	<f:selectItem itemValue="Thessaloniki" itemLabel="City - Thessaloniki" />
</h:selectOneMenu>

As described in previous examples, we have three possible ways to render and populate our dropdown list:

  1. Hardcoded value in a f:selectItem tag.
  2. Generated values using a Map and passed into the fore-mentioned tag.
  3. Generate values using an Object Array and passed again into the f:selectItem tag, then represent the value using a var attribute.

1. Backing Bean

Here is the backing bean that will hold and generate the required data for the values of our dropdown list.

UserBean.java

package com.javacodegeeks.enterprise.jsf;

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
@SessionScoped
public class UserBean implements Serializable{

	private static final long serialVersionUID = 4256272866128337548L;

	public String favoriteCar1;
	public String favoriteCar2;
	public String favoriteCar3;
	
	public String getFavoriteCar1() {
		return favoriteCar1;
	}
	public void setFavoriteCar1(String favoriteCar1) {
		this.favoriteCar1 = favoriteCar1;
	}
	public String getFavoriteCar2() {
		return favoriteCar2;
	}
	public void setFavoriteCar2(String favoriteCar2) {
		this.favoriteCar2 = favoriteCar2;
	}
	public String getFavoriteCar3() {
		return favoriteCar3;
	}
	public void setFavoriteCar3(String favoriteCar3) {
		this.favoriteCar3 = favoriteCar3;
	}
	
	
	//generated by map
	private static Map<String, Object> favoriteCar2Value;
	static
	{
		favoriteCar2Value = new LinkedHashMap<String, Object>();
		
		favoriteCar2Value.put("BMW Series 1 - 116", "116"); //label, value
		favoriteCar2Value.put("BMW Series 1 - 118", "118");
		favoriteCar2Value.put("BMW Series 1 - 120", "120");
	}
	
	public Map<String, Object> getFavoriteCar2Value()
	{
		return favoriteCar2Value;
	}
	
	//generated by object array
	public static class Car
	{
		public String carLabel;
		public String carValue;
		
		public Car(String carLabel, String carValue)
		{
			this.carLabel = carLabel;
			this.carValue = carValue;
		}
		
		public String getCarLabel()
		{
			return carLabel;
		}
		
		public String getCarValue()
		{
			return carValue;
		}
	}
	
	public Car[] car3List;
	
	public Car[] getFavoriteCar3Value()
	{
		car3List = new Car[3];
		
		car3List[0] = new Car("BMW Series 3 - 316", "316");
		car3List[1] = new Car("BMW Series 3 - 318", "318");
		car3List[2] = new Car("BMW Series 3 - 320", "320");
	
		return car3List;
	}
	
}

2. JSF Pages

The welcome page:

index.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"
      xmlns:f="http://java.sun.com/jsf/core" >
 
    <h:body>
    	<h1>JSF 2.2 Dropdown List Example</h1>
    	
    	<h:form>
    		1. Hardcoded with "f:selectItem" :
    		<br/>
    		
    		<h:selectOneMenu value="#{user.favoriteCar1}">
    			<f:selectItem itemValue="520" itemLabel="BMW Series 5 - 520" />
    			<f:selectItem itemValue="525" itemLabel="BMW Series 5 - 525" />
    			<f:selectItem itemValue="535" itemLabel="BMW Series 5 - 535" />
    		</h:selectOneMenu>
    		
    		<br/><br/>
    		
    		2. Generated by Map:
    		<br/>
    		
    		<h:selectOneMenu value="#{user.favoriteCar2}">
    			<f:selectItems value="#{user.favoriteCar2Value}" />
    		</h:selectOneMenu>
    		
    		<br/><br/>
    		
    		3. Generated by Object Array; access with "var"
    		<br/>
    		<h:selectOneMenu value="#{user.favoriteCar3}">
    			<f:selectItems value="#{user.favoriteCar3Value}" var="c"
    				itemLabel="#{c.carLabel}" itemValue="#{c.carValue}"	/>
    		</h:selectOneMenu>
    		
    		<br/>
    		
    		<h:commandButton value="Submit" action="response"/>
    		<h:commandButton value="Reset" type="reset"/>
    	</h:form>
    </h:body>
</html>

And the results page:
response.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 2.2 Dropdown List - Response Page</h1>
    	
    	<ol>
    		<li>user.favoriteCar1 : #{user.favoriteCar1}</li>
    		<li>user.favoriteCar2 : #{user.favoriteCar2}</li>
    		<li>user.favoriteCar3 : #{user.favoriteCar3}</li>
    	</ol>	
    
    </h:body>
</html>

3. Demo

Show time!!!

img1

What happened after clicking submit?

img2

This was an example of ListBox in JSF 2.0. You can also download the source code for this example: DropdownListJSF

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