Question

这是使用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，并且可能从bundle属性文件中获取最新信息。

我们还尝试了以下方法：

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());

我期待的行为是：

启动tomcat并点击页面，然后显示“Hello World”
将包含“Hello World”的属性文件更改为“Goodbye Earth”
使用servlet清除缓存
点击页面，期待看到'Goodbye Earth'

所以问题是，ResourceBundle.clearCache（）实际上是如何工作的？还有一些我们需要清除的通用文件缓存吗？

Answer 1

这对我有用：

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

备注：

在Java 1.6 中添加了
ResourceBundle.clearCache()
不要使用静态resourceBundle属性，请使用调用ResourceBundle.getBundle()后的clearCache()方法方法

Answer 2

我不相信你可以影响已经创建的ResourceBundle实例的重新加载，因为它已经创建了它的内部控件类。您可以尝试将此作为初始化捆绑包的替代方法：

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

Answer 3

我找到了这个解决方案（适用于tomcat）：

使用自定义ResourceBundle.Control（因为我需要UTF8）
将getTimeToLive添加为“Perception”描述
强制重装标志
“ResourceBundle.clearCache”不起作用

如何致电：

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

也许this post可以解决您的问题。

Answer 5

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 6

如果您可以拦截资源包的第一次创建，则此方法有效：

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);
}

如何清除ResourceBundle缓存

6 个答案: