springmvc获取request,response的方法

最新推荐文章于 2023-12-17 19:21:10 发布

青草萋萋

最新推荐文章于 2023-12-17 19:21:10 发布

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分类专栏： springmvc 文章标签： response request session application

本文链接：https://blog.youkuaiyun.com/zhangqin18710923356/article/details/78092813

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本文介绍了Spring MVC中处理HTTP请求的两种方式：通过@RequestMapping注解直接处理请求和利用监听器获取请求上下文。同时深入探讨了RequestContextListener的作用及其如何帮助在控制器中获取request和response对象。

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1.最简单方式：参数

@RequestMapping("/test")

@RequestMapping(value = "/getStuinfo.rst", method = RequestMethod.GET)
@ResponseBody
public void saveTest(HttpServletRequest req, HttpServletResponse resp){
　　

}

2..加入监听器，然后在代码里面获取

需要注意的是如果直接使用这个工具类，则会抛出一个空指针异常。原因是

需要先在web.xml配置RequestContextListener监听器:

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

HttpServletRequest req = ((ServletRequestAttributes)RequestContextHolder.getRequestAttributes()).getRequest();
HttpServletResponse resp = ((ServletWebRequest)RequestContextHolder.getRequestAttributes()).getResponse();

（在Spring API中提供了一个非常便捷的工具类RequestContextHolder，能够在Controller中获取request对象和response对象）

原理

RequestContextListener实现了 ServletRequestListener ,在其覆盖的requestInitialized(ServletRequestEvent requestEvent)方法中,将request最终设置到了RequestContextHolder中.

public class RequestContextListener implements ServletRequestListener {

private static final String REQUEST_ATTRIBUTES_ATTRIBUTE =
RequestContextListener.class.getName() + ".REQUEST_ATTRIBUTES";

@Override
public void requestInitialized(ServletRequestEvent requestEvent) {
if (!(requestEvent.getServletRequest() instanceof HttpServletRequest)) {
throw new IllegalArgumentException(
"Request is not an HttpServletRequest: " + requestEvent.getServletRequest());
}
HttpServletRequest request = (HttpServletRequest) requestEvent.getServletRequest();//从事件对象中获取request对象
ServletRequestAttributes attributes = new ServletRequestAttributes(request);//将request设置到servletRequestAttributes中
request.setAttribute(REQUEST_ATTRIBUTES_ATTRIBUTE, attributes);//反过来将servletRequestAttributes设置到request中
LocaleContextHolder.setLocale(request.getLocale());
RequestContextHolder.setRequestAttributes(attributes);//再将servletRequestAttributes设置到requestContextHolder中
}