springboot+thymeleaf国际化之LocaleResolver接口的示例

springboot中大部分有默认配置所以开发起项目来非常迅速，仅对需求项做单独配置覆盖即可

spring采用的默认区域解析器是AcceptHeaderLocaleResolver，根据request header中的accept-language值来解析locale，并且是不可变的。

那么想要实现国际化，就要使用SessionLocaleResolver或者CookieLocaleResolver。正如类的名字所示，是按session或cookie中储存的locale值来解析locale。

我就以SessionLocaleResolver举例：

1.建立一个配置类

									package com.example.config;

									import org.springframework.context.annotation.Bean;

									import org.springframework.context.annotation.Configuration;

									import org.springframework.context.support.ResourceBundleMessageSource;

									import org.springframework.web.servlet.LocaleResolver;

									import org.springframework.web.servlet.i18n.SessionLocaleResolver;

									/**

									 * Created by wq on 2016/8/15.

									 */

									@Configuration

									public class SpringMVC_config {

									  @Bean(name="localeResolver")

									  public LocaleResolver localeResolverBean() {

									    return new SessionLocaleResolver();

									  }

									//  @Bean(name="messageSource")

									//  public ResourceBundleMessageSource resourceBundleMessageSource(){

									//    ResourceBundleMessageSource source=new ResourceBundleMessageSource();

									//    source.setBasename("messages");

									//    return source;

									//  }

									}

注意 name="localeResolver" 是必须的

优先级如下：

session中对应属性（3中有说明）有值则按session来

如果没有但是SessionLocaleResolver设置了默认的locale则按默认值来

1 2	`// SessionLocaleResolver localeResolver=new SessionLocaleResolver();` `// localeResolver.setDefaultLocale(Locale.ENGLISH);`

再然后就还是按request header中的accept-language值来

2.建立对应的messages.properties

messages.properties

messages_en.properties

messages_zh_CN.properties

前面注释的代码则可以修改properties的前缀部分，name="messageSource" 同样是必须的

比如 setBasename("msg"); 对应properties则为

msg.properties

msg_en.properties

msg_zh_CN.properties

格式上sys.test=hello、sys.test=你好，应该无需赘述（可能转码会避免一些问题，我这里直接放的中文）

3.controller中切换locale

									package com.example.controller;

									import org.springframework.beans.factory.annotation.Autowired;

									import org.springframework.stereotype.Controller;

									import org.springframework.web.bind.annotation.RequestMapping;

									import org.springframework.web.servlet.LocaleResolver;

									import javax.servlet.http.HttpServletRequest;

									import javax.servlet.http.HttpServletResponse;

									import javax.servlet.http.HttpSession;

									import java.util.Locale;

									import static org.springframework.web.servlet.i18n.SessionLocaleResolver.LOCALE_SESSION_ATTRIBUTE_NAME;

									/**

									 * Created by Administrator on 2016/6/11.

									 */

									@Controller

									public class DemoController {

									  @Autowired

									  LocaleResolver localeResolver;

									  @RequestMapping("test")

									  public String test(HttpServletRequest request, HttpServletResponse response) {

									    HttpSession session=request.getSession();

									    localeResolver.setLocale(request,response,Locale.ENGLISH);

									    System.out.println(session.getAttribute(LOCALE_SESSION_ATTRIBUTE_NAME));

									    return "messages";

									  }

									}

这里org.springframework.web.servlet.i18n.SessionLocaleResolver.LOCALE_SESSION_ATTRIBUTE_NAME这个字符串常量则是session中默认属性名

可以看一下SessionLocaleResolver的部分源码

									public class SessionLocaleResolver extends AbstractLocaleContextResolver {

									  public static final String LOCALE_SESSION_ATTRIBUTE_NAME = SessionLocaleResolver.class.getName() + ".LOCALE";

									  public static final String TIME_ZONE_SESSION_ATTRIBUTE_NAME = SessionLocaleResolver.class.getName() + ".TIME_ZONE";

locale默认属性名为

org.springframework.web.servlet.i18n.SessionLocaleResolver.LOCALE

setLocale是抽象类AbstractLocaleContextResolver中方法

									public void setLocale(HttpServletRequest request, HttpServletResponse response, Locale locale) {

									  this.setLocaleContext(request, response, locale != null?new SimpleLocaleContext(locale):null);

									}

然后看SessionLocaleResolver中setLocaleContext

									public void setLocaleContext(HttpServletRequest request, HttpServletResponse response, LocaleContext localeContext) {

									  Locale locale = null;

									  TimeZone timeZone = null;

									  if(localeContext != null) {

									    locale = localeContext.getLocale();

									    if(localeContext instanceof TimeZoneAwareLocaleContext) {

									      timeZone = ((TimeZoneAwareLocaleContext)localeContext).getTimeZone();

									    }

									  }

									  WebUtils.setSessionAttribute(request, LOCALE_SESSION_ATTRIBUTE_NAME, locale);

									  WebUtils.setSessionAttribute(request, TIME_ZONE_SESSION_ATTRIBUTE_NAME, timeZone);

									}

本质上就是一些非空判断取默认，最终给session中的对应属性赋值

4.thymeleaf页面中调用

									<!DOCTYPE html>

									<html lang="zh_CN"

									   xmlns:th="http://www.thymeleaf.org">

									<head>

									  <title>msg</title>

									</head>

									<body>

									<h1 th:text="${#locale}"></h1>

									<h1 th:text="#{sys.test}"></h1>

									</body>

									</html>