建立多語言網(wǎng)站，可以獲得更多用戶流量。多語言網(wǎng)站被稱為國際化（i18n）,與本地化相反。

你比如京東、淘寶這類電商網(wǎng)站就是國際化的電商網(wǎng)站，它支持多國語言。

注意：國際化是一個由18個字符組成的單詞，第一個字符為i，最后一個字符為n，因此通常縮寫為 i18n。

Spring通過為不同的語言環(huán)境使用Spring攔截器，語言環(huán)境解析器和資源包，為國際化（i18n）提供了廣泛的支持。在本文中，我將知道您使用Spring Boot構(gòu)建了一個簡單的多語言網(wǎng)站。

你可以預(yù)覽一下示例：

在示例中，語言環(huán)境信息位于URL的參數(shù)上。語言環(huán)境信息將存儲在Cookie中，并且用戶不會在接下來的頁面中重新選擇語言。

http://localhost:8080/SomeContextPath/login1?lang=zh
http://localhost:8080/SomeContextPath/login1?lang=en

URL上的語言環(huán)境信息的另一個示例：

http://localhost:8080/SomeContextPath/zh/login2
http://localhost:8080/SomeContextPath/en/login2

12.1 創(chuàng)建Spring Boot項(xiàng)目

我在這里為以下語言創(chuàng)建2個屬性文件：中文、英語。

i18n / messages_zh.properties

label.password=密碼
label.submit=登陸label.title= 登陸頁面label.userName=用戶名

如果你的eclipse中顯示如下編碼形式：

label.password=\u5BC6\u7801
label.submit=\u767B\u9646label.title= \u767B\u9646\u9875\u9762label.userName=\u7528\u6237\u540D

修改首選項(xiàng)中的content Types下的：

第二步配置.proerties文件右鍵屬性配置，設(shè)置其字符編碼

i18n / messages_en.properties

label.password= Password
label.submit= Loginlabel.title= Login Pagelabel.userName= User Name

Eclipse支持使用消息編輯器來編輯文件的信息。

12.2 攔截器和LocaleResolver

您需要聲明2個Spring bean，包括localeResolver和messageResource。

LocaleResolver指定如何獲取用戶將使用的語言環(huán)境信息。CookieLocaleResolver將從Cookie讀取語言環(huán)境信息，以查找用戶以前使用的語言。

MessageResource 將加載屬性文件內(nèi)容

在Controller處理請求之前，它必須經(jīng)過攔截器，您需要在該攔截器中注冊LocaleChangeInterceptor,攔截器處理用戶的語言環(huán)境更改。

WebMvcConfig.JAVA

package me.laocat.i18n.config;
import org.springframework.context.MessageSource;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.support.ReloadableResourceBundleMessageSource;
import org.springframework.web.servlet.LocaleResolver;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.i18n.CookieLocaleResolver;
import org.springframework.web.servlet.i18n.LocaleChangeInterceptor;
@Configuration
public class WebMvcConfig implements WebMvcConfigurer {
@Bean(name = “localeResolver”)
public LocaleResolver getLocaleResolver() {
// Cookie本地化解析器
CookieLocaleResolver resolver = new CookieLocaleResolver();
resolver.setCookieDomain(“myAppLocaleCookie”);
// 60 分鐘
resolver.setCookieMaxAge(60 * 60);
return resolver;
}
@Bean(name = “messageSource”)
public MessageSource getMessageResource() {
// 可重新加載的資源包消息源
ReloadableResourceBundleMessageSource messageResource = new ReloadableResourceBundleMessageSource();
// 讀 i18n/messages_xxx.properties file.
// 例如: i18n/messages_en.properties
messageResource.setBasename(“classpath:i18n/messages”);
messageResource.setDefaultEncoding(“UTF-8”);
return messageResource;
}
@Override
public void addInterceptors(InterceptorRegistry registry) {
// 本地化修改攔截器
LocaleChangeInterceptor localeInterceptor = new LocaleChangeInterceptor();
localeInterceptor.setParamName(“lang”);
registry.addInterceptor(localeInterceptor).addPathPatterns(“/*”);
}
}

12.3 控制器和視圖

I18nController.java（在參數(shù)上設(shè)置本地化）

package me.laocat.i18n;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
public class I18nController {
@RequestMapping(value = { “/”, “/login1” })
public String staticResource(Model model) {
return “login1”;
}}

login1.html (Thymeleaf 視圖)

<!DOCTYPE HTML>
<html xmlns:th="http://www.thymeleaf.org">
   <head>
      <meta charset="UTF-8">
      <title th:utext="#{label.title}"></title>
   </head>
   <body>
      <div style="text-align: right;padding:5px;margin:5px 0px;background:#ccc;">
         <a th:href="@{/login1?lang=en}">Login (En)</a>
          |          <a th:href="@{/login1?lang=zh}">Login (Zh)</a>
      </div>
      <form method="post" action="">
         <table>
            <tr>
               <td>
                  <strong th:utext="#{label.userName}"></strong>
               </td>
               <td><input name="userName" /></td>
            </tr>
            <tr>
               <td>
                  <strong  th:utext="#{label.password}"></strong>
               </td>
               <td><input name="password" /></td>
            </tr>
            <tr>
               <td colspan="2">
                  <input type="submit" th:value="#{label.submit}" />
               </td>
            </tr>
         </table>
      </form>
   </body>
</html>

12.4 URL上的語言環(huán)境信息

如果您要構(gòu)建一個多語言網(wǎng)站，其語言環(huán)境信息位于URL上。您需要更改一些配置：

http://localhost:8080/SomeContextPath/en/login2
http://localhost:8080/SomeContextPath/zh/login2

創(chuàng)建2個類UrlLocaleInterceptor和UrlLocaleResolver

UrlLocaleInterceptor.java

package me.laocat.i18n.interceptors;
import java.util.Locale;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.LocaleResolver;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
import org.springframework.web.servlet.support.RequestContextUtils;
public class UrlLocaleInterceptor extends HandlerInterceptorAdapter {
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception {
LocaleResolver localeResolver = RequestContextUtils.getLocaleResolver(request);if (localeResolver == null) {
throw new IllegalStateException(“找不到LocaleResolver:不在DispatcherServlet請求中？?”);
}// 從LocaleResolver獲取區(qū)域設(shè)置
Locale locale = localeResolver.resolveLocale(request);
localeResolver.setLocale(request, response, locale);
return true;
}
}

UrlLocaleResolver.java

package me.laocat.i18n.resolver;
import java.util.Locale;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.LocaleResolver;
@Configuration
public class UrlLocaleResolver implements LocaleResolver {
private static final String URL_LOCALE_ATTRIBUTE_NAME = “URL_LOCALE_ATTRIBUTE_NAME”;
@Bean(name = “messageSource”)
@Override
public Locale resolveLocale(HttpServletRequest request) {
// ==> /SomeContextPath/en/…
// ==> /SomeContextPath/zh/…
// ==> /SomeContextPath/WEB-INF/pages/…
String uri = request.getRequestURI();
System.out.println(“URI=” + uri);
String prefixEn = request.getServletContext().getContextPath() + “/en/”;
String prefixZh = request.getServletContext().getContextPath() + “/zh/”;
Locale locale = null;
// English
if (uri.startsWith(prefixEn)) {
locale = Locale.ENGLISH;
}
// China
else if (uri.startsWith(prefixZh)) {
locale = new Locale(“zh”, “CN”);
}
if (locale != null) {
request.getSession().setAttribute(URL_LOCALE_ATTRIBUTE_NAME, locale);
}
if (locale == null) {
locale = (Locale) request.getSession().getAttribute(URL_LOCALE_ATTRIBUTE_NAME);
if (locale == null) {
locale = Locale.ENGLISH;
}
}
return locale;
}
@Override
public void setLocale(HttpServletRequest request, HttpServletResponse response, Locale locale) {
// Nothing
}
}

重新更改WebMvcConfig中的Interceptor配置：

WebMvcConfig.java

package me.laocat.i18n.config;
import org.springframework.context.MessageSource;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.support.ReloadableResourceBundleMessageSource;
import org.springframework.web.servlet.LocaleResolver;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.i18n.CookieLocaleResolver;
import org.springframework.web.servlet.i18n.LocaleChangeInterceptor;
import me.laocat.i18n.interceptors.UrlLocaleInterceptor;
import me.laocat.i18n.resolver.UrlLocaleResolver;
@Configuration
public class WebMvcConfig implements WebMvcConfigurer {
@Bean(name = “localeResolver”)
public LocaleResolver getLocaleResolver() {
// Cookie本地化解析器
// CookieLocaleResolver resolver = new CookieLocaleResolver();
// resolver.setCookieDomain(“myAppLocaleCookie”);
// 60 分鐘
// resolver.setCookieMaxAge(60 * 60);
LocaleResolver resolver = new UrlLocaleResolver();
return resolver;
}
@Bean(name = “messageSource”)
public MessageSource getMessageResource() {
// 可重新加載的資源包消息源
ReloadableResourceBundleMessageSource messageResource = new ReloadableResourceBundleMessageSource();
// 讀 i18n/messages_xxx.properties file.
// 例如: i18n/messages_en.properties
messageResource.setBasename(“classpath:i18n/messages”);
messageResource.setDefaultEncoding(“UTF-8”);
return messageResource;
}
@Override
public void addInterceptors(InterceptorRegistry registry) {
// 本地化修改攔截器
// LocaleChangeInterceptor localeInterceptor = new LocaleChangeInterceptor();
// localeInterceptor.setParamName(“lang”);
// registry.addInterceptor(localeInterceptor).addPathPatterns(“/*”);
UrlLocaleInterceptor localeInterceptor = new UrlLocaleInterceptor();
registry.addInterceptor(localeInterceptor).addPathPatterns(“/en/*”, “/zh/*”);
}
}

控制器：

I18nController2.java（URL上的語言環(huán)境）

package me.laocat.i18n.controller;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
public class I18nController2 {
@RequestMapping(value = “/{locale:en|zh}/login2”)
public String login2(Model model) {
return “login2”;
}}

login2.html (Thymeleaf 視圖)

<!DOCTYPE HTML>
<html xmlns:th="http://www.thymeleaf.org">
   <head>
      <meta charset="UTF-8">
      <title th:utext="#{label.title}"></title>
   </head>
   <body>
      <div style="text-align: right;padding:5px;margin:5px 0px;background:#ccc;">
         <a th:href="@{/en/login2}">Login (English)</a>
          |          <a th:href="@{/zh/login2}">Login (China)</a>
      </div>
      <form method="post" action="">
         <table>
            <tr>
               <td>
                  <strong th:utext="#{label.userName}"></strong>
               </td>
               <td><input name="userName" /></td>
            </tr>
            <tr>
               <td>
                  <strong  th:utext="#{label.password}"></strong>
               </td>
               <td><input name="password" /></td>
            </tr>
            <tr>
               <td colspan="2">
                  <input type="submit" th:value="#{label.submit}" />
               </td>
            </tr>
         </table>
      </form>
   </body>
</html>

運(yùn)行應(yīng)用程序：

http://localhost:8080/zh/login2