[java] www.2cto.com
LocalStrings_es.properties
LocalStrings_ja.properties
LocalStrings.properties
分别表示三种语言的属性文件。LocalStrings.properties属性文件是默认的属性文件。看LocalStrings.properties属性中的内容：
[java]
fileLogger.alreadyStarted=File Logger has already been started
fileLogger.notStarted=File Logger has not yet been started
tomcatLogger.alreadyStarted=Tomcat Logger has already been started
tomcatLogger.notStarted=Tomcat Logger has not yet been started
ResourceBundle类通过getBundle方法获取，参数是属性文件的包名家名字前缀，上面就是包名加LocalStrings。通过getString(String key)方法获取属性文件中的参数：
现在来看代码sm.getString("fileLogger.alreadyStarted")，sm是StringManager的实例，在FileLogger中已经初始化：
[java]
private StringManager sm =StringManager.getManager(Constants.Package);
Constants.Package得到包的名字，getManager方法代码如下：
[java]
public synchronized static StringManager getManager(String packageName) {
StringManager mgr = (StringManager)managers.get(packageName);
if (mgr == null) {
mgr = new StringManager(packageName);//新建一个StringManager
managers.put(packageName, mgr);
}
return mgr;
}
代码很好理解，如果已经有StringManager实例了就直接从managers（这是一个Hashtable）中拿，没有就新建一个。看StringManager的构造方法：
[java]
private StringManager(String packageName) {
String bundleName = packageName + ".LocalStrings";
bundle = ResourceBundle.getBundle(bundleName);
}
看到我们熟悉的ResourceBundle类了，根据上面的讲解，ResourceBundle.getBundle(bundleName)能拿到默认的属性文件，也就是上面的LocalStrings.properties文件。再回到sm.getString("fileLogger.alreadyStarted")，看sm的getString方法：
[java]
public String getString(String key) {
if (key == null) {
String msg = "key is null";
throw new NullPointerException(msg);
}
String str = null;
try {
str = bundle.getString(key);
} catch (MissingResourceException mre) {
str = "Cannot find message associated with key '" + key + "'";
}
return str;
}
重点是budle.getString(key)，这句代码能拿到LocalStrings.properties文件的key属性（这里是fileLogger.alreadyStarted）的值，即File Logger has already been started。这样我们便能定义多个属性文件，一个表示英文，一个表示汉语，一个属性文件表示一个语言，就能实现应用的国际化了。
作者：haitao111313