JSF—来自Springbean和数据库的资源包

这是一个在许多论坛上都被问到的问题，但我找不到任何精确和具体的答案。在我看来，即使是被接受的答案也是不完整的，因此我将尝试发布我解决这个问题的完整尝试，希望在这个问题上建立一个精确的问题+答案

我试图让资源包在JSF中工作。资源包来自Springbean，它应该从任意外部系统（即数据库）加载

现在我将绕过数据库查询，使用一个模拟的资源包来保持清楚

这是我的资源包业务实现，我从本论坛的其他帖子中收集到：

public class TesteResBundle extends ReloadableResourceBundleMessageSource {

    private final Map<String, Map<String, String>> properties = new HashMap<String, Map<String, String>>();

    public TesteResBundle() {
        reload();
    }

    @Override
    protected MessageFormat resolveCode(String code, Locale locale) {
        String msg = getText(code, locale);
        MessageFormat result = createMessageFormat(msg, locale);
        return result;
    }

    @Override
    protected String resolveCodeWithoutArguments(String code, Locale locale) {
        return getText(code, locale);
    }

    private String getText(String code, Locale locale) {
        Map<String, String> localized = properties.get(code);
        String textForCurrentLanguage = null;
        if (localized != null) {
            textForCurrentLanguage = localized.get(locale.getLanguage());
            if (textForCurrentLanguage == null) {
                textForCurrentLanguage = localized.get(Locale.ENGLISH.getLanguage());
            }
        }
        return textForCurrentLanguage != null ? textForCurrentLanguage : code;
    }

    public void reload() {
        properties.clear();
        properties.putAll(loadTexts());
    }

    protected Map<String, Map<String, String>> loadTexts() {

        Map<String, Map<String, String>> m = new HashMap<String, Map<String, String>>();
        Map<String, String> v = new HashMap<String, String>();
        v.put("en", "good");
        v.put("pt", "bom");
        v.put("en_US", "bom");
        m.put("prop", v);

        v = new HashMap<String, String>();
        v.put("en", "bad");
        v.put("pt", "mau");
        v.put("en_US", "bom");
        m.put("pror", v);
        return m;
    }
}

}

自定义EL解析器在faces-config.xml中定义：

<el-resolver>pt.teste.pojo.MessageSourcePropertyResolver</el-resolver>

除以下情况外：

org.springframework.context.NoSuchMessageException: No message found under code 'prop' for locale 'en_US'.
org.springframework.context.support.DelegatingMessageSource.getMessage(DelegatingMessageSource.java:65)
pt.teste.pojo.MessageSourcePropertyResolver.getValue(MessageSourcePropertyResolver.java:18)
com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
org.apache.el.parser.AstValue.getValue(AstValue.java:169)
org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:189)
com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:194)
javax.faces.component.ComponentStateHelper.eval(ComponentStateHelper.java:182)
javax.faces.component.UIOutput.getValue(UIOutput.java:169)
com.sun.faces.renderkit.html_basic.HtmlBasicInputRenderer.getValue(HtmlBasicInputRenderer.java:205)
com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.getCurrentValue(HtmlBasicRenderer.java:355)
com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeEnd(HtmlBasicRenderer.java:164)
javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.encodeRecursive(HtmlBasicRenderer.java:312)
com.sun.faces.renderkit.html_basic.GroupRenderer.encodeChildren(GroupRenderer.java:105)
javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845)
javax.faces.component.UIComponent.encodeAll(UIComponent.java:1779)
com.sun.faces.renderkit.html_basic.CompositeRenderer.encodeChildren(CompositeRenderer.java:78)
javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845)
javax.faces.component.UIComponent.encodeAll(UIComponent.java:1779)
javax.faces.render.Renderer.encodeChildren(Renderer.java:168)
javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845)
javax.faces.component.UIComponent.encodeAll(UIComponent.java:1779)
javax.faces.component.UIComponent.encodeAll(UIComponent.java:1782)
com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:402)
com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:125)
org.springframework.faces.webflow.FlowViewHandler.renderView(FlowViewHandler.java:99)
com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:121)
com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
org.springframework.faces.mvc.JsfView.renderMergedOutputModel(JsfView.java:85)
org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:262)
org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1180)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:950)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
javax.servlet.http.HttpServlet.service(HttpServlet.java:734)
javax.servlet.http.HttpServlet.service(HttpServlet.java:847)

我认为我可能在这里遗漏了一些东西，特别是在SpringConfig中的MessageSourcebean定义中。我怀疑这是因为在解析资源包时，没有调用TestResBundle的方法

---

感谢您在这个问题上提供的任何帮助。

我实际上已经为这个问题制定了一个解决方案。因为我在春天做了我的第一个婴儿步骤，所以如果一个春天的专家能够回顾一下这个方法，那将是一件好事，因为我不认为它是以“春天的方式”完成的。但是，如果其他一切都失败了，我会坚持这个不太漂亮的解决办法

我的web应用程序中通常有一个保存配置工件的单例。现在它实际上只是保存了对Spring应用程序上下文的引用：

public class ApplicationConfig {

    private static ApplicationConfig instance = new ApplicationConfig();

    private ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");

    private ApplicationConfig(){

    }

    public static ApplicationConfig instance(){
        return instance;
    }

    public ApplicationContext getApplicationContext(){
        return context;
    }
}

我放弃了以前的资源包实现，而是扩展了AbstractMessageSource:

public class TesteMessageSource extends AbstractMessageSource {

    @Override
    protected MessageFormat resolveCode(String key, Locale locale) {
        // This is just a dummy method.
        // It should lookup in a Map created in this same 
        // class for the correct key/locale resource value
        return createMessageFormat(key, Locale.US);
    }

    @Override
    protected String resolveCodeWithoutArguments(String key, Locale locale){
        // This is just a dummy method.
        // It should lookup in a Map created in this same 
        // class for the correct key/locale resource value
        return "dummyString";
    }
}

然后我注意到传递给定制EL解析器的基本参数实际上是DelegatingMessageSource的一个实例。根据Spring文档：“将所有调用委托给父MessageSource的Empty MessageSource”。因此，我修改了自定义EL解析器，从singleton获取Spring应用程序上下文，然后获取messageResource bean，并将其设置为DelegatingMessageSource实例的父MessageSource：

public class MessageSourcePropertyResolver extends SpringBeanFacesELResolver /*implements MessageSourceAware */{

    public Object getValue(ELContext elContext, Object base, Object property)
        throws ELException {

        if (base instanceof MessageSource && property instanceof String) {
            DelegatingMessageSource delegatingMessageSource = (DelegatingMessageSource) base;
            BeanFactory factory = ApplicationConfig.instance().getApplicationContext();
            MessageSource messageSource = (MessageSource) factory.getBean("messageSource");
            delegatingMessageSource.setParentMessageSource(messageSource);

            String result = delegatingMessageSource.getMessage((String) property, new Object[] {}, getLocale());
            if (result != null) {
                elContext.setPropertyResolved(true);
            }

            return result;
        }

        return super.getValue(elContext, base, property);
    }

    private Locale getLocale() {
        FacesContext context = FacesContext.getCurrentInstance();
        return context.getExternalContext().getRequestLocale();
    }
}

Spring messageSource bean配置变为：

<bean id="messageSource" class="pt.teste.pojo.TesteMessageSource">
</bean>

Facelets xtml组件中的消息资源访问变为：

<h:outputText value="${messageSource['prop.aaa']}" />

其中，prop.aaa作为“property”参数传递给自定义EL解析器，我们只需查找该“property”和也传递给解析器的区域设置

通过这种方式，一切都正常工作，但我几乎可以肯定，这可以以更好、正确的方式完成，比如将已配置的MessageSource传递给自定义EL解析器。我的意思是传递一个自定义MessageSource的实例，或者至少传递一个默认MessageSource，其父级已经设置为自定义MessageSource

public class TesteMessageSource extends AbstractMessageSource {

    @Override
    protected MessageFormat resolveCode(String key, Locale locale) {
        // This is just a dummy method.
        // It should lookup in a Map created in this same 
        // class for the correct key/locale resource value
        return createMessageFormat(key, Locale.US);
    }

    @Override
    protected String resolveCodeWithoutArguments(String key, Locale locale){
        // This is just a dummy method.
        // It should lookup in a Map created in this same 
        // class for the correct key/locale resource value
        return "dummyString";
    }
}

public class MessageSourcePropertyResolver extends SpringBeanFacesELResolver /*implements MessageSourceAware */{

    public Object getValue(ELContext elContext, Object base, Object property)
        throws ELException {

        if (base instanceof MessageSource && property instanceof String) {
            DelegatingMessageSource delegatingMessageSource = (DelegatingMessageSource) base;
            BeanFactory factory = ApplicationConfig.instance().getApplicationContext();
            MessageSource messageSource = (MessageSource) factory.getBean("messageSource");
            delegatingMessageSource.setParentMessageSource(messageSource);

            String result = delegatingMessageSource.getMessage((String) property, new Object[] {}, getLocale());
            if (result != null) {
                elContext.setPropertyResolved(true);
            }

            return result;
        }

        return super.getValue(elContext, base, property);
    }

    private Locale getLocale() {
        FacesContext context = FacesContext.getCurrentInstance();
        return context.getExternalContext().getRequestLocale();
    }
}

<bean id="messageSource" class="pt.teste.pojo.TesteMessageSource">
</bean>

<h:outputText value="${messageSource['prop.aaa']}" />