In JSF, <h:selectOneMenu /> tag is used to render a dropdown box – HTML select element with “size=1” attribute.
//JSF...
<h:selectOneMenu value="#{user.favCoffee1}">
<f:selectItem itemValue="Cream Latte" itemLabel="Coffee3 - Cream Latte" />
<f:selectItem itemValue="Extreme Mocha" itemLabel="Coffee3 - Extreme Mocha" />
<f:selectItem itemValue="Buena Vista" itemLabel="Coffee3 - Buena Vista" />
</h:selectOneMenu>
//HTML output...
<select name="j_idt6:j_idt8" size="1">
<option value="Cream Latte">Coffee3 - Cream Latte</option>
<option value="Extreme Mocha">Coffee3 - Extreme Mocha</option>
<option value="Buena Vista">Coffee3 - Buena Vista</option>
</select>
h:selectOneMenu example
A JSF 2.0 example to show the use of “h:selectOneMenu” tag to render a dropdow box, 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 Object array 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 dropdown box values.
package com.mkyong;
import java.io.Serializable;
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 favCoffee1;
public String favCoffee2;
public String favCoffee3;
public String getFavCoffee1() {
return favCoffee1;
}
public void setFavCoffee1(String favCoffee1) {
this.favCoffee1 = favCoffee1;
}
public String getFavCoffee2() {
return favCoffee2;
}
public void setFavCoffee2(String favCoffee2) {
this.favCoffee2 = favCoffee2;
}
public String getFavCoffee3() {
return favCoffee3;
}
public void setFavCoffee3(String favCoffee3) {
this.favCoffee3 = favCoffee3;
}
//Generated by Map
private static Map<String,Object> coffee2Value;
static{
coffee2Value = new LinkedHashMap<String,Object>();
coffee2Value.put("Coffee2 - Cream Latte", "Cream Latte"); //label, value
coffee2Value.put("Coffee2 - Extreme Mocha", "Extreme Mocha");
coffee2Value.put("Coffee2 - Buena Vista", "Buena Vista");
}
public Map<String,Object> getFavCoffee2Value() {
return coffee2Value;
}
//Generated by Object array
public static class Coffee{
public String coffeeLabel;
public String coffeeValue;
public Coffee(String coffeeLabel, String coffeeValue){
this.coffeeLabel = coffeeLabel;
this.coffeeValue = coffeeValue;
}
public String getCoffeeLabel(){
return coffeeLabel;
}
public String getCoffeeValue(){
return coffeeValue;
}
}
public Coffee[] coffee3List;
public Coffee[] getFavCoffee3Value() {
coffee3List = new Coffee[3];
coffee3List[0] = new Coffee("Coffee3 - Cream Latte", "Cream Latte");
coffee3List[1] = new Coffee("Coffee3 - Extreme Mocha", "Extreme Mocha");
coffee3List[2] = new Coffee("Coffee3 - Buena Vista", "Buena Vista");
return coffee3List;
}
}
2. JSF Page
A JSF page to demonstrate the use “h:selectOneMenu” 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 dropdown box example</h1>
<h:form>
1. Hard-coded with "f:selectItem" :
<h:selectOneMenu value="#{user.favCoffee1}">
<f:selectItem itemValue="Cream Latte" itemLabel="Coffee3 - Cream Latte" />
<f:selectItem itemValue="Extreme Mocha" itemLabel="Coffee3 - Extreme Mocha" />
<f:selectItem itemValue="Buena Vista" itemLabel="Coffee3 - Buena Vista" />
</h:selectOneMenu>
<br /><br />
2. Generated by Map :
<h:selectOneMenu value="#{user.favCoffee2}">
<f:selectItems value="#{user.favCoffee2Value}" />
</h:selectOneMenu>
<br /><br />
3. Generated by Object array and iterate with var :
<h:selectOneMenu value="#{user.favCoffee3}">
<f:selectItems value="#{user.favCoffee3Value}" var="c"
itemLabel="#{c.coffeeLabel}" itemValue="#{c.coffeeValue}" />
</h:selectOneMenu>
<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 dropdown box example</h1>
<h2>result.xhtml</h2>
<ol>
<li>user.favCoffee1 : #{user.favCoffee1}</li>
<li>user.favCoffee2 : #{user.favCoffee2}</li>
<li>user.favCoffee3 : #{user.favCoffee3}</li>
</ol>
</h:body>
</html>
3. Demo
When “submit” button is clicked, link to “result.xhtml” page and display the submitted dropdown box values.
How to pre-select a dropdown box value?
The value of “f:selectItems” tag is selected if it matched to the “value” of “h:selectOneMenu” tag. In above example, if you set “favCoffee1″ property to “Extreme Mocha” :
@ManagedBean(name="user")
@SessionScoped
public class UserBean{
public String favCoffee1 = "Extreme Mocha";
//...
The “favCoffee1″ dropdown box, values “Extreme Mocha” is selected by default.