JSF - Internationalization

國際化是一種狀態消息、GUI組件標籤、貨幣、日期不在程序中硬編碼的技術。相反，它們存儲在原始碼之外的資源包中並動態檢索。JSF提供了一種非常方便的方法來處理資源包。

要使JSF應用程式內部化，需要執行以下步驟。

Step 1: Define properties files

爲每個區域設置創建屬性文件。名稱應爲<文件名>語言環境>.properties格式。

文件名中可以省略默認區域設置。

messages.properties

greeting = Hello World!

messages_fr.properties

greeting = Bonjour tout le monde!

Step 2: Update faces-config.xml

faces-config.xml

<application>
   <locale-config>
      <default-locale>en</default-locale>
      <supported-locale>fr</supported-locale>
   </locale-config>
   
   <resource-bundle>
      <base-name>com.tutorialspoint.messages</base-name>
      <var>msg</var>
   </resource-bundle>
</application>

Step 3: Use resource-bundle var

home.xhtml

<h:outputText value = "#{msg['greeting']}" />

Example Application

讓我們創建一個測試JSF應用程式來測試JSF中的國際化。

Step	Description
1	Create a project with a name helloworld under a package com.tutorialspoint.test as explained in the JSF - First Application chapter.
2	Create resources folder under src → mai folder.
3	Create com folder under src → main → resources folder.
4	Create tutorialspoint folder under src → main → resources → com folder.
5	Create messages.properties file under src → main → resources → com → tutorialspoint folder. Modify it as explained below.
6	Create messages_fr.properties file under src → main → resources → com → tutorialspoint folder. Modify it as explained below.
7	Create faces-config.xml in WEB-INFf older as explained below.
8	Create UserData.java under package com.tutorialspoint.test as explained below.
9	Modify home.xhtml as explained below. Keep the rest of the files unchanged.
10	Compile and run the application to make sure the business logic is working as per the requirements.
11	Finally, build the application in the form of war file and deploy it in Apache Tomcat Webserver.
12	Launch your web application using appropriate URL as explained below in the last step.

messages.properties

greeting = Hello World!

messages_fr.properties

greeting = Bonjour tout le monde!

faces-config.xml

<?xml version = "1.0" encoding = "UTF-8"?>
<faces-config
   xmlns = "http://java.sun.com/xml/ns/javaee"
   xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation = "http://java.sun.com/xml/ns/javaee 
   http://java.sun.com/xml/ns/javaee/web-facesconfig_2_0.xsd"
   version = "2.0">
   
   <application>
      <locale-config>
         <default-locale>en</default-locale>
         <supported-locale>fr</supported-locale>
      </locale-config>
      
      <resource-bundle>
         <base-name>com.tutorialspoint.messages</base-name>
         <var>msg</var>
      </resource-bundle>
   </application>
</faces-config>

UserData.java

package com.tutorialspoint.test;

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

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

@ManagedBean(name = "userData", eager = true)
@SessionScoped
public class UserData implements Serializable {
   private static final long serialVersionUID = 1L;
   private String locale;

   private static Map<String,Object> countries;
      static {
      
      countries = new LinkedHashMap<String,Object>();
      countries.put("English", Locale.ENGLISH);
      countries.put("French", Locale.FRENCH);
   }

   public Map<String, Object> getCountries() {
      return countries;
   }

   public String getLocale() {
      return locale;
   }

   public void setLocale(String locale) {
      this.locale = locale;
   }

   //value change event listener
   public void localeChanged(ValueChangeEvent e) {
      String newLocaleValue = e.getNewValue().toString();
      
      for (Map.Entry<String, Object> entry : countries.entrySet()) {
         
         if(entry.getValue().toString().equals(newLocaleValue)) {
            FacesContext.getCurrentInstance()
               .getViewRoot().setLocale((Locale)entry.getValue());         
         }
      }
   }
}

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>Internalization Language Example</h2>
      
      <h:form>
         <h3><h:outputText value = "#{msg['greeting']}" /></h3>
         
         <h:panelGrid columns = "2"> 
            Language : 
            <h:selectOneMenu value = "#{userData.locale}" onchange = "submit()"
               valueChangeListener = "#{userData.localeChanged}">
               <f:selectItems value = "#{userData.countries}" /> 
            </h:selectOneMenu> 
         </h:panelGrid> 
      
      </h:form>
   </h:body>
</html>

完成所有更改後，讓我們像在JSF-First應用程式一章中那樣編譯和運行應用程式。如果您的應用程式一切正常，這將產生以下結果。

從下拉列表中更改語言。您將看到以下輸出。