详解Java中用于国际化的locale类

Locale locale = Locale.getDefault()

public static final Locale CANADA
public static final Locale CANADA_FRENCH
public static final Locale CHINA
public static final Locale CHINESE
public static final Locale ENGLISH
public static final Locale FRANCE
public static final Locale FRENCH
public static final Locale GERMAN
public static final Locale GERMANY
public static final Locale ITALIAN
public static final Locale ITALY
public static final Locale JAPAN
public static final Locale JAPANESE
public static final Locale KOREA
public static final Locale KOREAN
public static final Locale PRC
public static final Locale ROOT
public static final Locale SIMPLIFIED_CHINESE
public static final Locale TAIWAN
public static final Locale TRADITIONAL_CHINESE
public static final Locale UK
public static final Locale US

Locale locale = Locale.SIMPLIFIED_CHINESE

Locale(String language)
Locale(String language, String country)
Locale(String language, String country, String variant)

Locale local = new Locale("zh", "CN");

Locale[] ls = Locale.getAvailableLocales();

for (Locale locale:ls) {
  System.out.println("locale :"+locale);
}

All Locales: ja_JP, es_PE, en, ja_JP_JP, es_PA, sr_BA, mk, es_GT, ar_AE, no_NO, sq_AL, bg, ar_IQ, ar_YE, hu, pt_PT, el_CY, ar_QA, mk_MK, sv, de_CH, en_US, fi_FI, is, cs, en_MT, sl_SI, sk_SK, it, tr_TR, zh, th, ar_SA, no, en_GB, sr_CS, lt, ro, en_NZ, no_NO_NY, lt_LT, es_NI, nl, ga_IE, fr_BE, es_ES, ar_LB, ko, fr_CA, et_EE, ar_KW, sr_RS, es_US, es_MX, ar_SD, in_ID, ru, lv, es_UY, lv_LV, iw, pt_BR, ar_SY, hr, et, es_DO, fr_CH, hi_IN, es_VE, ar_BH, en_PH, ar_TN, fi, de_AT, es, nl_NL, es_EC, zh_TW, ar_JO, be, is_IS, es_CO, es_CR, es_CL, ar_EG, en_ZA, th_TH, el_GR, it_IT, ca, hu_HU, fr, en_IE, uk_UA, pl_PL, fr_LU, nl_BE, en_IN, ca_ES, ar_MA, es_BO, en_AU, sr, zh_SG, pt, uk, es_SV, ru_RU, ko_KR, vi, ar_DZ, vi_VN, sr_ME, sq, ar_LY, ar, zh_CN, be_BY, zh_HK, ja, iw_IL, bg_BG, in, mt_MT, es_PY, sl, fr_FR, cs_CZ, it_CH, ro_RO, es_PR, en_CA, de_DE, ga, de_LU, de, es_AR, sk, ms_MY, hr_HR, en_SG, da, mt, pl, ar_OM, tr, th_TH_TH, el, ms, sv_SE, da_DK, es_HN

Locale locale = new Locale("ja", "JP");

Locale locale = new Locale("en");

// Locale的构造函数
Locale(String language)
Locale(String language, String country)
Locale(String language, String country, String variant)

Object             clone()
boolean           equals(Object object)
static Locale[]       getAvailableLocales()
String             getCountry()
static Locale         getDefault()
String             getDisplayCountry(Locale locale)
final String         getDisplayCountry()
final String         getDisplayLanguage()
String             getDisplayLanguage(Locale locale)
String             getDisplayName(Locale locale)
final String         getDisplayName()
final String         getDisplayVariant()
String             getDisplayVariant(Locale locale)
String             getISO3Country()
String             getISO3Language()
static String[]       getISOCountries()
static String[]       getISOLanguages()
String             getLanguage()
String             getVariant()
synchronized int       hashCode()
synchronized static void   setDefault(Locale locale)
final String         toString()

import java.util.Locale;
import java.util.Date;
import java.util.Calendar;
import java.text.SimpleDateFormat;
import java.text.DateFormat;

/**
 * Locale 的测试程序
 */
public class LocaleTest {

  public static void main(String[] args) {
    // 2种不同的Locale的创建方法
    testDiffDateLocales();

    // 显示所有的Locales
    testAllLocales();
  }


  /**
   * 2种不同的Locale的创建方法
   */
  private static void testDiffDateLocales() {
    // date为2013-09-19 14:22:30
    Date date = new Date(113, 8, 19, 14, 22, 30);

    // 创建“简体中文”的Locale
    Locale localeCN = Locale.SIMPLIFIED_CHINESE;
    // 创建“英文/美国”的Locale
    Locale localeUS = new Locale("en", "US");

    // 获取“简体中文”对应的date字符串
    String cn = DateFormat.getDateInstance(DateFormat.MEDIUM, localeCN).format(date);
    // 获取“英文/美国”对应的date字符串
    String us = DateFormat.getDateInstance(DateFormat.MEDIUM, localeUS).format(date);

    System.out.printf("cn=%s\nus=%s\n", cn, us);
  }

  /**
   * 显示所有的Locales
   */
  private static void testAllLocales() {
    Locale[] ls = Locale.getAvailableLocales();

    System.out.print("All Locales: ");
    for (Locale locale:ls) {
      System.out.printf(locale+", ");
    }
    System.out.println();
  }
}

3.使用ResouceBundle读取国际化资源文件

ResourceBundle资源包包含特定语言环境的对象。使用其可以加载并读取语言环境资源。
1.轻松的本地化或者翻译成不同的语言
2.一次处理多个语言环境
3.以后可以轻松的进行修改，一遍支持更多的语言环境。
 
当程序需要特定于语言环境的对象时，它使用getBundle()方法加载ResourceBundle类

ResourceBundle rb = ResourceBundle.getBundle(“res.MessageBundle”, currentLocale);

其中，res.MessageBundle代表的是我们在src下建立了一个res文件夹，而res文件夹下有一个名为MessageBundle.properteis的资源文件。我们允许在此建立多个国际化资源文件：

MessageBundle_zh_CN.properties;MessageBundle_en_US.properteis;

其中MessageBundle就是要在构造ResourceBundle时使用的字符串，这个名字合法即可，不需要特定约束。后边的名字一定要遵循规则，

resourceName_language_country.properteis;

然后我们使用rb.getString(key);就可以获取资源文件中的Key对应的value.
使用Struts1.x实现国际化自动切换

查看Struts源码就可以发现，语言环境信息就存放在session中，通过this.setLocale(request, locale);
所以要实现国际化就要在页面上点击超链接经过Action的时候改变会话中Locale（语言环境）的值。在Action中：

//接受客户端传过来的语言请求信息 
String language = request.getParameter(“myLanguage”); 
 
//定义语言地区信息 
Locale currentLocale = null; 
 
//根据不同的请求创建不同的语言环境信息 
if (“zh”.equals(language)) { 
  currentLocale = new Locale(“zh”, “CN”); 
} else if (“en”.equals(language)) { 
  currentLocale = new Locale(“en”, “US”); 
} 
 
//…… 
//将session中的信息更改掉  
this.setLocale(request, currentLocale); 
 
//当然，在页面显示资源文件信息的时候采用如下这种方式： 
 
//<bean:message key=”key” />