JSF-actionListener

ユーザーがh：commandButtonやh：linkなどのコンポーネントを操作すると、JSFは2つの方法で処理できるアクションイベントを発生させます。

S.No

Technique & Description

1

Method Binding

UIコンポーネントの_actionListener_属性でマネージドBeanメソッドの名前を渡します。

2

ActionListener

ActionListenerインターフェースを実装し、実装クラス名をUIコンポーネントの_actionListener_属性に渡します。

メソッドのバインド

メソッドを定義する

public void updateData(ActionEvent e) {
   data = "Hello World";
}

上記の方法を使用してください

<h:commandButton id = "submitButton"
   value = "Submit" action = "#{userData.showResult}"
   actionListener = "#{userData.updateData}"/>
</h:commandButton>

ActionListener

ActionListenerを実装する

public class UserActionListener implements ActionListener {

   @Override
   public void processAction(ActionEvent arg0)
   throws AbortProcessingException {

     //access userData bean directly
      UserData userData = (UserData) FacesContext.getCurrentInstance().
      getExternalContext().getSessionMap().get("userData");
      userData.setData("Hello World");
   }
}

リスナーメソッドを使用する

<h:commandButton id = "submitButton1"
   value = "Submit" action = "#{userData.showResult}" >
   <f:actionListener type = "com.finddevguides.test.UserActionListener"/>
</h:commandButton>

応用例

テストJSFアプリケーションを作成して、JSFのactionListenerをテストしましょう。

Step	Description
1	Create a project with a name helloworld under a package com.finddevguides.test as explained in the JSF - First Application chapter.
2	Modify UserData.java file as explained below.
3	Create UserActionListener.java file under a package com.finddevguides.test. Modify it as explained below.
4	Modify home.xhtml as explained below. Keep the rest of the files unchanged.
5	Modify result.xhtml as explained below. Keep the rest of the files unchanged.
6	Compile and run the application to make sure the business logic is working as per the requirements.
7	Finally, build the application in the form of war file and deploy it in Apache Tomcat Webserver.
8	Launch your web application using appropriate URL as explained below in the last step.

UserData.java

package com.finddevguides.test;

import java.io.Serializable;
import java.util.LinkedHashMap;
import java.util.Map;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;
import javax.faces.event.ValueChangeEvent;

@ManagedBean(name = "userData", eager = true)
@SessionScoped
public class UserData implements Serializable {
   private static final long serialVersionUID = 1L;
   private static Map<String,String> countryMap;
   private String data = "sample data";

   public String showResult() {
      return "result";
   }

   public void updateData(ActionEvent e) {
      data="Hello World";
   }

   public String getData() {
      return data;
   }

   public void setData(String data) {
      this.data = data;
   }
}

UserActionListener.java

package com.finddevguides.test;

import javax.faces.context.FacesContext;
import javax.faces.event.AbortProcessingException;
import javax.faces.event.ActionEvent;
import javax.faces.event.ActionListener;

public class UserActionListener implements ActionListener {

   @Override
   public void processAction(ActionEvent arg0)
   throws AbortProcessingException {

     //access userData bean directly
      UserData userData = (UserData) FacesContext.getCurrentInstance().
      getExternalContext().getSessionMap().get("userData");
      userData.setData("Hello World");
   }
}

home.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:head>
      <title>JSF tutorial</title>
   </h:head>

   <h:body>
      <h2>actionListener Examples</h2>

      <h:form>
         <h2>Method Binding</h2>
         <hr/>

         <h:commandButton id = "submitButton"
            value = "Submit" action = "#{userData.showResult}"
            actionListener = "#{userData.updateData}"/>
         </h:commandButton>
         <h2>ActionListener interface</h2>
         <hr/>

         <h:commandButton id = "submitButton1"
            value = "Submit" action = "#{userData.showResult}" >
            <f:actionListener
               type = "com.finddevguides.test.UserActionListener"/>
         </h:commandButton>
      </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:f = "http://java.sun.com/jsf/core"
   xmlns:h = "http://java.sun.com/jsf/html">

   <h:head>
      <title>JSF Tutorial!</title>
   </h:head>

   <h:body>
      <h2>Result</h2>
      <hr/>
      #{userData.data}
   </h:body>
</html>

すべての変更を完了したら、JSF-最初のアプリケーションの章で行ったようにアプリケーションをコンパイルして実行します。すべてがアプリケーションで問題ない場合、次の結果が生成されます。

JSF actionListener result

送信ボタンをクリックします。次の結果が表示されます。

JSF actionListener result1

Jsf-actionlistener-tag