How to pass new hidden value to backing bean in JSF

来源：互联网发布：js获取标签classname 编辑：程序博客网时间：2024/05/16 09:42

https://www.mkyong.com/jsf2/how-to-pass-new-hidden-value-to-backing-bean-in-jsf/

In some cases, you may need to pass a new hidden value to a backing bean. Generally, there are two ways :

1. HTML Tag + getRequestParameterMap()

Render hidden field with plain HTML input, hard-coded new hidden value and access in backing bean via getRequestParameterMap() method.

JSF…

<h:form id="myForm">    <input type="hidden" name="hidden1" value="this is hidden2" />    <h:commandButton value="submit" action="#{user.action}" /></h:form>

Managed bean…

@ManagedBean(name="user")@SessionScopedpublic class UserBean{public String action(){   String value = FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("hidden1");}}

2. JSF Tag + JavaScript

Render hidden field via “h:inputHidden” tag, assign new value via JavaScript.

JSF…

<script type="text/javascript">   function setHiddenValue(new_value){document.getElementById('myForm:hidden2').value = new_value;   }</script><h:form id="myForm">   <h:inputHidden id="hidden2" value="#{user.hidden2}" />   <h:commandButton value="submit" action="..." onclick="setHiddenValue('this is hidden2');" /></h:form>

Managed bean…

@ManagedBean(name="user")@SessionScopedpublic class UserBean{public String hidden2;public void setHidden2(String hidden2) {this.hidden2 = hidden2;}}

JSF 2.0 new hidden value example

A JSF 2.0 example, to demonstrate the use of above two methods to pass a new hidden value to a backing bean.

1. Managed Bean

A simple managed bean, assign name as “user”.

package com.mkyong.form;import javax.faces.bean.ManagedBean;import javax.faces.bean.SessionScoped;import javax.faces.context.FacesContext;import java.io.Serializable;@ManagedBean(name="user")@SessionScopedpublic class UserBean implements Serializable {public String hidden1;public String hidden2;public String getHidden2() {return hidden2;}public void setHidden2(String hidden2) {this.hidden2 = hidden2;}public String getHidden1() {return hidden1;}public void setHidden1(String hidden1) {this.hidden1 = hidden1;}public String action(){    String value = FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("hidden1");    setHidden1(value);    return "start";}}

2. View Page

Two pages for demonstration.

demo.xhtml – two ways to pass a new hidden value.

<?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:head><script type="text/javascript">   function setHiddenValue(new_value){     document.getElementById('myForm:hidden2').value = new_value;   }</script></h:head>    <h:body>     <h1>JSF 2 pass new hidden value to backing bean</h1>     <h:form id="myForm">       <input type="hidden" name="hidden1" value="this is hidden2" />       <h:inputHidden id="hidden2" value="#{user.hidden2}" />       <h:commandButton value="submit" action="#{user.action}"                               onclick="setHiddenValue('this is hidden2');" />     </h:form>    </h:body></html>

start.xhtml – display hidden value via “h:outputText” 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">    <h:body>    <h1>JSF 2 pass new hidden value to backing bean</h1> <ol>   <li>Hidden1 = <h:outputText value="#{user.hidden1}" /></li>   <li>Hidden2 = <h:outputText value="#{user.hidden2}" /></li></ol>    </h:body></html>

3. Demo

URL : http://localhost:8080/JavaServerFaces/

Download Source Code

0 0