在Spring MVC中动态生成可用语言列表 [英] Dynamically generate a list of available languages in Spring MVC

问题描述

我在Spring MVC 3中设置了i18n，它正常工作。
有几个文件，每个都有自己的语言：messages_en.properties，messages_de.properties等。

在我的一个JSP中，我需要显示用户使用所有可用的语言组合，我希望这个列表是动态的，即从服务器中的现有语言文件即时生成。

有没有内置方法生成此列表？或者我必须诉诸检查文件所在的文件夹并解析它们？

谢谢！

Nacho

解决方案

好的，找到了两个解决方案。对于这两个，假定它们正在Spring MVC @Controller -annotated类中执行。每个都将产生一个HashMap（语言），其中的关键字是2个字母的ISO语言代码，并且值是语言名称（在当前语言环境中，在这些示例中是一个名为的静态变量HSConstants.currentLocale ）

1.- @millhouse提交的一个（见上文/下面），它有一些调整后工作：

  
 HashMap languages = new HashMap（）; 
 final String defaultMessage =NOT FOUND; 
 HashMap availableLocales = new HashMap（）; 
 for（Locale locale：Locale.getAvailableLocales（））{
 String msg = rrbms.getMessage（currentLanguage，null，defaultMessage，locale）; 
 if（！defaultMessage.equals（msg）&&！availableLocales.containsKey（locale.getLanguage（）））{
 availableLocales.put（locale.getLanguage（），locale）; 
} 
} 
 for（String c：availableLocales.keySet（））{
 languages.put（c，availableLocales.get（c）.getDisplayLanguage（HSConstants.currentLocale）） ; 
} 
 model.addAttribute（languages，languages）; 
  

此解决方案要求您在每种语言的.properties文件中设置一个带有语言的条目（在上面的例子中，它将是'currentLanguage'）。对于ecample，在messages_it.properties中，必须有如下条目：currentLanguage = Italiano

2.-原始方法，即直接访问文件夹/文件：假设文件语言在/ WEB-INF / languages中，并具有fr-messages的基本名称：

  
 HashMap语言= new HashMap（）; 
 String languagesFolderPath = request.getSession（）。getServletContext（）。getRealPath（/ WEB-INF / languages）; 
文件夹=新文件（languagesFolderPath）; 
文件[] listOfFiles = folder.listFiles（）; （int i = 0; i< listOfFiles.length; i ++）{
 String fileName = listOfFiles [i] .getName（）; 
 
 
 if（fileName.startsWith（fr-messages_）&& fileName.endsWith（。properties））{
 //提取下划线和.properties扩展名之间的语言代码
 String language = fileName.substring（12，fileName.indexOf（。properties））; 
 Locale l = new Locale（language）; 
 languages.put（language，l.getDisplayLanguage（HSConstants.currentLocale））; 
} 
} 
 model.addAttribute（languages，languages）; 
 
  

然后，在您的JSP中，使用语言 map：

 < select name =language> 
< c：forEach items =$ {languages}var =language> 
< c：choose> 
< c：when test =$ {platform.language == language.key}> 
< option value =$ {language.key}selected =SELECTED> $ {language.value}< / option> 
< / c：当> 
< c：否则> 
< option value =$ {language.key}> $ {language.value}< / option> 
< / c：否则> 
< / c：choose> 
< / c：forEach> 
< / select> 
  

I have set up i18n in Spring MVC 3, and it is working correctly. There are several files, each with its own language: messages_en.properties, messages_de.properties, etc.

In one of my JSPs, I need to show the users a combo with all available languages, and I would like this list to be dynamic i.e. generated on the fly from the existing language files in the server.

Is there any built-in method to generate this list? Or do I have to resort to check the folder where the language files reside and parse them?

Thanks!

Nacho

解决方案

Ok, two solutions found. For both, assume they are being executed inside a Spring MVC @Controller-annotated class. Each will produce a HashMap (languages) in which the key is the 2-letter ISO language code, and the value the language name (in the current Locale, which in these examples is a static variable called HSConstants.currentLocale)

1.- The one submitted by @millhouse (see above/below), which works after a bit of tweaking:

    HashMap languages = new HashMap();  
    final String defaultMessage = "NOT FOUND";  
    HashMap availableLocales = new HashMap();  
    for (Locale locale : Locale.getAvailableLocales()) {  
        String msg = rrbms.getMessage("currentLanguage", null, defaultMessage, locale);  
        if (!defaultMessage.equals(msg) && !availableLocales.containsKey(locale.getLanguage())){  
            availableLocales.put(locale.getLanguage(), locale);  
        }  
    }  
    for (String c : availableLocales.keySet()){  
        languages.put(c, availableLocales.get(c).getDisplayLanguage(HSConstants.currentLocale));  
    }  
    model.addAttribute("languages", languages);  

This solution requires that, in each of your language .properties files, you set an entry with the language (in the example above, it would be 'currentLanguage'). For ecample, in messages_it.properties, there must be an entry like this: currentLanguage=Italiano

2.- Raw method, i.e. accesing the folder/files directly: assuming the files languages are in /WEB-INF/languages, and have a basename of fr-messages:

HashMap languages = new HashMap();  
String languagesFolderPath = request.getSession().getServletContext().getRealPath("/WEB-INF/languages");  
File folder = new File(languagesFolderPath);  
File[] listOfFiles = folder.listFiles();  

for (int i = 0; i < listOfFiles.length; i++){  
   String fileName = listOfFiles[i].getName();  
   if (fileName.startsWith("fr-messages_") && fileName.endsWith(".properties")){  
      // Extract the language code, which is between the underscore and the .properties extension  
      String language = fileName.substring(12, fileName.indexOf(".properties"));  
      Locale l = new Locale(language);  
      languages.put(language, l.getDisplayLanguage(HSConstants.currentLocale));  
   }  
}  
model.addAttribute("languages", languages);  

And then, in your JSP, render the select box using the languages map:

<select name="language">
    <c:forEach items="${languages}" var="language">
        <c:choose>
            <c:when test="${platform.language == language.key}">
                <option value="${language.key}" selected="SELECTED">${language.value}</option>
            </c:when>
            <c:otherwise>
                <option value="${language.key}">${language.value}</option>
            </c:otherwise>
        </c:choose>                         
    </c:forEach>
</select>

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