ResourceBundle 學習與使用

 學習了 Tomcat 的StringManager 類之後，學習了一下ResourceBundle類，對國際化管理又有了進一步的瞭解

通過Locale類來表示特定的地理、政治和文化地區，所以可以將屬性文件在結尾的地方加上相應的locale地區，即可顯示該地區特定的string

代碼如下：

package com.fw.resource;

import java.text.MessageFormat;
import java.util.Hashtable;
import java.util.Locale;
import java.util.Map;
import java.util.MissingResourceException;
import java.util.ResourceBundle;

public class ResourceManager {
	
	/**
	 * the ResourceBundle for this ResourceManager
	 */
	private final ResourceBundle bundle;
	private final Locale locale;
	
	/**
	 * use the Single pattern
	 * initialize the bundle and locale
	 */
	private ResourceManager(String name, Locale locale) {
		String bundleName = name + ".LocalStrings";
		ResourceBundle bnd = null;
		try {
			bnd = ResourceBundle.getBundle(bundleName, locale);
		} catch (MissingResourceException e) {
			ClassLoader cl = Thread.currentThread().getContextClassLoader();
			try {
				bnd = ResourceBundle.getBundle(bundleName, locale, cl);
			} catch (MissingResourceException e1) {
				//Ignore
			}
		}
		bundle = bnd;
		if(bundle!=null){
			this.locale = bundle.getLocale();
		} else {
			this.locale = null;
		}
	}
	
	public String getString(String key){
		if(key == null){
			String msg = " key may not have a null value";
			
			throw new IllegalArgumentException(msg);
		}
		
		String str = null;
		try {
			if(bundle!=null){
				str = bundle.getString(key);
			}
		} catch (MissingResourceException e) {
			str = null;
		}
		return str;
	}
	
	public String getString(String key, final Object... objects) {
		String value = getString(key);
		if(value == null){
			value = key;
		}
		
		MessageFormat mf = new MessageFormat(value);
		mf.setLocale(locale);
		return mf.format(objects, new StringBuffer(), null).toString();
	}
	
	/**
	 * identify the Locale this StringManager is associate with
	 */
	public Locale getLocale(){
		return locale;
	}
	
	private static final Map<String, Map<Locale, ResourceManager>> managers = 
		new Hashtable<String, Map<Locale, ResourceManager>>();
	
	
	public static final synchronized ResourceManager getManager(String packageName){
		return getManager(packageName, Locale.getDefault());
	}

	/**
	 * Get ResourceManager by special packageName and locale, if the mgr is  already exists,
	 * it will be reuse, or a new ResourceManager will be created and return;
	 * @param packageName
	 * @param locale
	 * @return
	 */
	public static final synchronized ResourceManager getManager(String packageName, Locale locale) {
		Map<Locale, ResourceManager> map = managers.get(packageName);
		if(map == null){
			map = new Hashtable<Locale, ResourceManager>();
			managers.put(packageName, map);
		}
		ResourceManager mgr = map.get(locale);
		if(mgr == null) {
			mgr = new ResourceManager(packageName, locale);
			map.put(locale, mgr);
		}
		return mgr;
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		System.out.println(Locale.getDefault());
		System.out.println(Locale.CHINA);
		ResourceManager mgr = getManager("com.fw.regex", Locale.getDefault());
		String str = mgr.getString("name");
		System.out.println(str);
	}

}

屬性文件可以定義在某個包裏即可