SpringMVC Http请求工具代码类

在SpringMVC的源代码中也提供了一个封装过的ThreadLocal，其中保存了每次请求的HttpServletRequest对象，（详细请看org.springframework.web.context.request.ServletRequestAttributes的源代码） 。

这样我们就可以进行简单封装一下写一个工具进行使用：

*当然必不可少的一点一定记得，在web.xml里必须要有相应的配置来支持 

<listener>
    <listener-class>org.springframework.web.context.request.RequestContextListener</listener-class>
</listener>  

工具类代码：

package samples.utils;  

import java.util.Arrays;
import java.util.Collection;
import java.util.Locale;  

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import javax.sql.DataSource;  

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.beans.factory.NoUniqueBeanDefinitionException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.MessageSource;
import org.springframework.core.convert.ConversionService;
import org.springframework.core.io.ResourceLoader;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.ui.context.Theme;
import org.springframework.util.ClassUtils;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.web.context.support.WebApplicationContextUtils;
import org.springframework.web.servlet.LocaleResolver;
import org.springframework.web.servlet.ThemeResolver;
import org.springframework.web.servlet.support.RequestContextUtils;  

/**
 * SpringMVC通用工具
 * @author
 */
public final class WebContextHolder {  

    private static final Logger LOGGER = LoggerFactory.getLogger(WebContextHolder.class);
    private static final WebContextHolder INSTANCE = new WebContextHolder();  

    public WebContextHolder get() {
        return INSTANCE;
    }  

    private WebContextHolder() {
        super();
    }  

    // --------------------------------------------------------------------------------------------------------------  

    public HttpServletRequest getRequest() {
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.currentRequestAttributes();
        return attributes.getRequest();
    }  

    public HttpSession getSession() {
        return getSession(true);
    }  

    public HttpSession getSession(boolean create) {
        return getRequest().getSession(create);
    }  

    public String getSessionId() {
        return getSession().getId();
    }  

    public ServletContext getServletContext() {
        return getSession().getServletContext();    // servlet2.3
    }  

    public Locale getLocale() {
        return RequestContextUtils.getLocale(getRequest());
    }  

    public Theme getTheme() {
        return RequestContextUtils.getTheme(getRequest());
    }  

    public ApplicationContext getApplicationContext() {
        return WebApplicationContextUtils.getWebApplicationContext(getServletContext());
    }  

    public ApplicationEventPublisher getApplicationEventPublisher() {
        return (ApplicationEventPublisher) getApplicationContext();
    }  

    public LocaleResolver getLocaleResolver() {
        return RequestContextUtils.getLocaleResolver(getRequest());
    }  

    public ThemeResolver getThemeResolver() {
        return RequestContextUtils.getThemeResolver(getRequest());
    }  

    public ResourceLoader getResourceLoader() {
        return (ResourceLoader) getApplicationContext();
    }  

    public ResourcePatternResolver getResourcePatternResolver() {
        return (ResourcePatternResolver) getApplicationContext();
    }  

    public MessageSource getMessageSource() {
        return (MessageSource) getApplicationContext();
    }  

    public ConversionService getConversionService() {
        return getBeanFromApplicationContext(ConversionService.class);
    }  

    public DataSource getDataSource() {
        return getBeanFromApplicationContext(DataSource.class);
    }  

    public Collection<String> getActiveProfiles() {
        return Arrays.asList(getApplicationContext().getEnvironment().getActiveProfiles());
    }  

    public ClassLoader getBeanClassLoader() {
        return ClassUtils.getDefaultClassLoader();
    }  

    private <T> T getBeanFromApplicationContext(Class<T> requiredType) {
        try {
            return getApplicationContext().getBean(requiredType);
        } catch (NoUniqueBeanDefinitionException e) {
            LOGGER.error(e.getMessage(), e);
            throw e;
        } catch (NoSuchBeanDefinitionException e) {
            LOGGER.warn(e.getMessage());
            return null;
        }
    }  

}