SpringMVC 学习 01 - springmvc在普通类中获取HttpServletRequest对象

spring mvc在普通类中获取HttpServletRequest对象需要做2个步骤：

1、在web.xml文件中加如下配置

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

在RequestContextListener类中有如下代码，其中红色标注的为关键代码：

public class RequestContextListener implements ServletRequestListener {

 

...

...

...

 

public void requestInitialized(ServletRequestEvent requestEvent) {

if (!(requestEvent.getServletRequest() instanceof HttpServletRequest)) {

throw new IllegalArgumentException("");

}

HttpServletRequest request = (HttpServletRequest) requestEvent.getServletRequest();

ServletRequestAttributes attributes = new ServletRequestAttributes(request);

request.setAttribute(REQUEST_ATTRIBUTES_ATTRIBUTE, attributes);

LocaleContextHolder.setLocale(request.getLocale());

RequestContextHolder.setRequestAttributes(attributes);

}

...

...

...

}

 

 

public class ServletRequestAttributes extends AbstractRequestAttributes {

 

...

...

...

 

private final HttpServletRequest request;

 

...

...

...

 

/**

 * Create a new ServletRequestAttributes instance for the given request.

 * @param request current HTTP request

 */

public ServletRequestAttributes(HttpServletRequest request) {

Assert.notNull(request, "Request must not be null");

this.request = request;

}

}

2、在普通类中获取对象

HttpServletRequest request =  ((ServletRequestAttributes)RequestContextHolder.getRequestAttributes()).getRequest();