如何清除ResourceBundle缓存

Question

这是一个使用Guice在Tomcat上运行的webapp。根据文档，我们应该能够调用ResourceBundle.clearCache();来清除ResourceBundle缓存，并可能从捆绑软件属性文件中获取最新版本。

我们也试过如下：

Class klass = ResourceBundle.getBundle("my.bundle").getClass().getSuperclass(); 
Field field = klass.getDeclaredField("cacheList"); 
field.setAccessible(true); 
ConcurrentHashMap cache = (ConcurrentHashMap) field.get(null); 
cache.clear(); // If i debug here I can see the cache is now empty! 

和

ResourceBundle.clearCache(this.class.getClassLoader()); 

行为，我希望是：

1. 启动Tomcat和打了一个网页，它说'Hello World'
2. 更改属性文件包含'你好世界”到“再见地球
3. 清除使用servlet
4. 点击的页面，希望看到缓存”再见地球

所以问题是，如何在ResourceBundle.clearCache（）实际工作？还有我们需要清除的一些通用文件缓存吗？

Answer 1

我不相信你可以重新加载已经创建的ResourceBundle实例，因为它的内部控制类已经被创建。你可以试试这个为初始化你包的替代：

ResourceBundle.getBundle("my.bundle", new ResourceBundle.Control() { 
    @Override 
    public long getTimeToLive(String arg0, Locale arg1) { 
     return TTL_DONT_CACHE; 
    } 
}); 

Answer 2

也许this post可以解决你的问题。

Answer 3

我发现这个解决方案（使用Tomcat作品）：

• 使用自定义的ResourceBundle.Control（因为我需要UTF8）
• 添加getTimeToLive为 “感知” 的描述
• 力的重装标志
• 的 “ResourceBundle.clearCache” 不工作

如何拨打：

ResourceBundle bundle = ResourceBundle.getBundle("yourfile", new UTF8Control()); 

自定义类：

public class UTF8Control extends Control 
{ 
    public ResourceBundle newBundle(
     String baseName, 
     Locale locale, 
     String format, 
     ClassLoader loader, 
     boolean reload) 
    throws IllegalAccessException, InstantiationException, IOException 
    { 
     // The below is a copy of the default implementation. 
     String bundleName = toBundleName(baseName, locale); 
     String resourceName = toResourceName(bundleName, "properties"); 
     ResourceBundle bundle = null; 
     InputStream stream = null; 

     // FORCE RELOAD because needsReload doesn't work and reload is always false 
     reload = true; 

     if (reload) { 
      URL url = loader.getResource(resourceName); 
      if (url != null) { 
       URLConnection connection = url.openConnection(); 
       if (connection != null) { 
        connection.setUseCaches(false); 
        stream = connection.getInputStream(); 
       } 
      } 
     } 
     else { 
      stream = loader.getResourceAsStream(resourceName); 
     } 

     if (stream != null) { 
      try { 
       // Only this line is changed to make it to read properties files as UTF-8. 
       bundle = new PropertyResourceBundle(new InputStreamReader(stream, "UTF-8")); 
      } 
      finally { 
       stream.close(); 
      } 
     } 
     return bundle; 
    } 

    // ASK NOT TO CACHE 
    public long getTimeToLive(String arg0, Locale arg1) { 
     return TTL_DONT_CACHE; 
    } 
} 

Answer 4

this is one more possibility to clear cache 
Class<ResourceBundle> type = ResourceBundle.class; 
     try { 
      Field cacheList = type.getDeclaredField("cacheList"); 
      cacheList.setAccessible(true); 

      ((Map<?, ?>) cacheList.get(ResourceBundle.class)).clear(); 
     } 
     catch (Exception e) { 

      system.out.print("Failed to clear ResourceBundle cache" + e); 
     } 

Answer 5

这为我工作：

ResourceBundle.clearCache(); 
ResourceBundle resourceBundle= ResourceBundle.getBundle("YourBundlePropertiesFile"); 
String value = resourceBundle.getString("your_resource_bundle_key"); 

注：

1. 012在Java 1.6中添加了
2. 不要使用静态resourceBundle属性，使用 ResourceBundle.getBundle()方法调用clearCache() 方法。

Answer 6

这工作，当且仅当可以拦截的第一个创建资源包：

while (true) { 
    ResourceBundle resourceBundle = ResourceBundle.getBundle("SystemMessages", new Locale("hu", "HU"), 
      new ResourceBundle.Control() { 
       @Override 
       public List<String> getFormats(String baseName) { 
        return ResourceBundle.Control.FORMAT_PROPERTIES; 
       } 

       @Override 
       public ResourceBundle newBundle(String baseName, Locale locale, String format, ClassLoader loader, boolean reload) throws IllegalAccessException, InstantiationException, IOException { 
        System.err.println(this.toBundleName(baseName, locale) + ": " + format + " - " + reload); 
        return super.newBundle(baseName, locale, format, loader, reload); 
       } 

       @Override 
       public long getTimeToLive(String baseName, Locale locale) { 
        long ttl = 1000; 
        System.err.println(this.toBundleName(baseName, locale) + " - " + ttl + "ms"); 
        return ttl; 
       } 

       @Override 
       public boolean needsReload(String baseName, Locale locale, String format, ClassLoader loader, ResourceBundle bundle, long loadTime) { 
        System.err.println(baseName + "_" + locale + " - " + new Date(loadTime)); 
        return true; 
       } 
      }); 
    System.out.println(resourceBundle.getString("display.first_name") + ": John"); 
    System.out.println(resourceBundle.getString("display.last_name") + ": Doe"); 
    Thread.sleep(5000); 
}