JSF 2 listbox example

时间：2023-03-09 07:43:24
JSF 2 listbox example

In JSF, <h:selectOneListbox /> tag is used to render a single select listbox – HTML select element with “size” attribute.

//JSF...

<h:selectOneListbox value="#{user.favYear1}">

   	<f:selectItem itemValue="2000" itemLabel="Year1 - 2000" />

   	<f:selectItem itemValue="2010" itemLabel="Year1 - 2010" />

   	<f:selectItem itemValue="2020" itemLabel="Year1 - 2020" />

</h:selectOneListbox>
//HTML output...

<select name="j_idt6:j_idt8" size="3">

	<option value="2000">Year1 - 2000</option>

	<option value="2010">Year1 - 2010</option>

	<option value="2020">Year1 - 2020</option>

</select>

h:selectOneListbox example

A JSF 2.0 example to show the use of “h:selectOneListbox” tag to render a single select listbox, and populate the data in 3 different ways :

  • Hardcoded value in “f:selectItem” tag.
  • Generate values with a Map and 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 listbox 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 favYear1;

	public String favYear2;

	public String favYear3;

	//getter and setter methods

	//Generated by Map

	private static Map<String,Object> year2Value;

	static{

		year2Value = new LinkedHashMap<String,Object>();

		year2Value.put("Year2 - 2000", "2000"); //label, value

		year2Value.put("Year2 - 2010", "2010");

		year2Value.put("Year2 - 2020", "2020");

	}

	public Map<String,Object> getFavYear2Value() {

		return year2Value;

	}

	//Generated by Object array

	public static class Year{

		public String yearLabel;

		public String yearValue;

		public Year(String yearLabel, String yearValue){

			this.yearLabel = yearLabel;

			this.yearValue = yearValue;

		}

		public String getYearLabel(){

			return yearLabel;

		}

		public String getYearValue(){

			return yearValue;

		}

	}

	public Year[] year3List;

	public Year[] getFavYear3Value() {

		year3List = new Year[3];

		year3List[0] = new Year("Year3 - 2000", "2000");

		year3List[1] = new Year("Year3 - 2010", "2010");

		year3List[2] = new Year("Year3 - 2020", "2020");

		return year3List;

	}

}

2. JSF Page

A JSF page to demonstrate the use “h:selectOneListbox” 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 listbox example</h1>

    	<h:form>

	        1. Hard-coded with "f:selectItem" :

   		<h:selectOneListbox value="#{user.favYear1}">

   			<f:selectItem itemValue="2000" itemLabel="Year1 - 2000" />

   			<f:selectItem itemValue="2010" itemLabel="Year1 - 2010" />

   			<f:selectItem itemValue="2020" itemLabel="Year1 - 2020" />

   		</h:selectOneListbox>

   		<br />

	        2. Generated by Map :

   		<h:selectOneListbox value="#{user.favYear2}">

   			<f:selectItems value="#{user.favYear2Value}" />

   		</h:selectOneListbox>

	        <br />

	        3. Generated by Object array and iterate with var :

   		<h:selectOneListbox value="#{user.favYear3}">

   			<f:selectItems value="#{user.favYear3Value}" var="y"

   			itemLabel="#{y.yearLabel}" itemValue="#{y.yearValue}" />

   		</h:selectOneListbox>

	        <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 listbox example</h1>

    	<h2>result.xhtml</h2>

    	<ol>

    		<li>user.favYear1 : #{user.favYear1}</li>

    		<li>user.favYear2 : #{user.favYear2}</li>

    		<li>user.favYear3 : #{user.favYear3}</li>

    	</ol>

    </h:body>

</html>

3. Demo

JSF 2 listbox example

When “submit” button is clicked, link to “result.xhtml” page and display the submitted listbox values.

JSF 2 listbox example

How to pre-select a listbox value?

The value of “f:selectItems” tag is selected if it matched to the “value” of “h:selectOneListbox” tag. In above example, if you set favYear1 property to “2010” :

@ManagedBean(name="user")

@SessionScoped

public class UserBean{

	public String favYear1 = "2010";

	//...

The “favYear1″ listbox, value “2010” is selected by default.

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