通常客戶端的語言特性,是經過cookie來傳遞的,也能夠經過request的請求中得到locale的值。 java
先看CookieGenerator.java web
public void addCookie(HttpServletResponse response, String cookieValue) { Assert.notNull(response, "HttpServletResponse must not be null"); Cookie cookie = createCookie(cookieValue); Integer maxAge = getCookieMaxAge(); if (maxAge != null) { cookie.setMaxAge(maxAge); } if (isCookieSecure()) { cookie.setSecure(true); } if (isCookieHttpOnly()) { cookie.setHttpOnly(true); } response.addCookie(cookie); if (logger.isDebugEnabled()) { logger.debug("Added cookie with name [" + getCookieName() + "] and value [" + cookieValue + "]"); } }
這個地方就是response中回寫cookie來存儲locale的值。cookieName表明的是cookie的key值。若是咱們採用的CookieLocaleResolver.java是本地的locale解析器。默認設置的cookieName是 spring
public static final String DEFAULT_COOKIE_NAME = CookieLocaleResolver.class.getName() + ".LOCALE";
繼承自LocaleResolver的兩個方法實現以下: cookie
public Locale resolveLocale(HttpServletRequest request) { // Check request for pre-parsed or preset locale. Locale locale = (Locale) request.getAttribute(LOCALE_REQUEST_ATTRIBUTE_NAME); if (locale != null) { return locale; } // Retrieve and parse cookie value. Cookie cookie = WebUtils.getCookie(request, getCookieName()); --批量在cookie中匹配對應key值的cookie if (cookie != null) { locale = StringUtils.parseLocaleString(cookie.getValue()); if (logger.isDebugEnabled()) { logger.debug("Parsed cookie value [" + cookie.getValue() + "] into locale '" + locale + "'"); } if (locale != null) { request.setAttribute(LOCALE_REQUEST_ATTRIBUTE_NAME, locale);--設置到request請求中,在spring的攔截器會使用時,攔截request時使用。 return locale; } } return determineDefaultLocale(request); --若是前面的cookie沒有讀取出來的話,讀取的是request中包含的locale信息。 } public void setLocale(HttpServletRequest request, HttpServletResponse response, Locale locale) { if (locale != null) { // Set request attribute and add cookie. request.setAttribute(LOCALE_REQUEST_ATTRIBUTE_NAME, locale); --設置請求中的locale信息 addCookie(response, locale.toString()); --添加cookie到response中,設置到客戶端中。 } else { // Set request attribute to fallback locale and remove cookie. request.setAttribute(LOCALE_REQUEST_ATTRIBUTE_NAME, determineDefaultLocale(request)); removeCookie(response); } }看一下攔截器對request的操做,是在類LocaleChangeInterceptor中引用:
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws ServletException { String newLocale = request.getParameter(this.paramName); --查看請求參數中是否有locale的參數名,感受spring這個地方的處理略顯粗糙了點 if (newLocale != null) { LocaleResolver localeResolver = RequestContextUtils.getLocaleResolver(request); --從spring的容器中獲取localeResolver的實現 if (localeResolver == null) { throw new IllegalStateException("No LocaleResolver found: not in a DispatcherServlet request?"); } localeResolver.setLocale(request, response, StringUtils.parseLocaleString(newLocale)); } // Proceed in any case. return true; }接下來查看的是:
public static LocaleResolver getLocaleResolver(HttpServletRequest request) { return (LocaleResolver) request.getAttribute(DispatcherServlet.LOCALE_RESOLVER_ATTRIBUTE); --在請求的屬性中是否有localeResolver的實現 }
調用方法是DispatcherServlet.java中: session
public static final String LOCALE_RESOLVER_ATTRIBUTE = DispatcherServlet.class.getName() + ".LOCALE_RESOLVER";這裏指定的是locale的解析類的key值。 DispatcherServlet也包含其餘的如上下文和主題等的生成。
初始化的時候指定對應的key值,對應到調用的地方是: mvc
protected void initStrategies(ApplicationContext context) { initMultipartResolver(context); initLocaleResolver(context); --初始化localeResolver initThemeResolver(context); initHandlerMappings(context); initHandlerAdapters(context); initHandlerExceptionResolvers(context); initRequestToViewNameTranslator(context); initViewResolvers(context); initFlashMapManager(context); }
初始化本地化解析的方法調用以下: app
private void initLocaleResolver(ApplicationContext context) { try { this.localeResolver = context.getBean(LOCALE_RESOLVER_BEAN_NAME, LocaleResolver.class);//bean的值是localeResolver,定義bean值的時候須要bean的id爲localeResolver. if (logger.isDebugEnabled()) { logger.debug("Using LocaleResolver [" + this.localeResolver + "]"); } } catch (NoSuchBeanDefinitionException ex) { // We need to use the default. this.localeResolver = getDefaultStrategy(context, LocaleResolver.class); //沒找到時候採起的默認策略的localeResolver爲org.springframework.web.servlet.i18n.AcceptHeaderLocaleResolver if (logger.isDebugEnabled()) { logger.debug("Unable to locate LocaleResolver with name '" + LOCALE_RESOLVER_BEAN_NAME + "': using default [" + this.localeResolver + "]"); } } }
spring的mvc攔截器會攔截客戶端的請求來抓取到合適的locale解析器來得到locale的屬性,從而經過resourceBundle來得到對應的屬性文件裏面的值。須要注意的點是bean的id須要設置成localeResolver。 this
分析一下i18n包下的幾個類: spa
AcceptHeaderLocaleResolver --是獲取請求頭中的locale對象 線程
CookieLocaleResolver --獲取的是cookie中傳遞的locale對象,若是cookie 不存在,獲取的也是請求頭中的locale對象。其中默認的cookieName是:
public static final String DEFAULT_COOKIE_NAME = CookieLocaleResolver.class.getName() + ".LOCALE";SessionLocaleResolver --是從session中來獲取的locale值,用會話來保持。默認的key值是:
public static final String LOCALE_SESSION_ATTRIBUTE_NAME = SessionLocaleResolver.class.getName() + ".LOCALE";FixedLocaleResolver -- 是獲取請求頭中的locale對象,不一樣點是能夠經過java代碼來寫入想要的locale對象。
上面只是spring的保持和傳遞locale對象的方式,也能夠經過線程的方式來將locale綁定到ThreadLocale上面。來保持在一次請求過程當中locale的值。取值的方式也能夠參照前面的幾種。
後續會加上ResourceBundle中調用的邏輯處理。