SpringMVC框架中,获得request对象的几种方式
1.最简单的方式(注解法)
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2.最麻烦的方法
a.在web.xml中配置一个监听
<listener> <listener-class> org.springframework.web.context.request.RequestContextListener </listener-class> </listener>
b.之后再程序里可以用下面的代码来获得
HttpServletRequest request = ((ServletRequestAttributes)RequestContextHolder.getRequestAttributes()).getRequest();
3.最直接的方法
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springMVC4中获取request和response对象有以下两种简单易用的方法:
1、在control层获取
在control层中获取HttpServletRequest和HttpServletResponse对象有以下两种简单方式:
1)通过方法参数直接在action类中获取
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@Controller
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class Action{
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@RequestMapping("/path")
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public String getReqAndRes(HttpServletRequest request, HttpServletResponse response){
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/** 相关业务代码 此时可以直接使用request response对象 */
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}
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}
2)利用spring web提供的@ModelAttribute注解
@ModelAttribute放在类方法的参数前面表示引用Model中的数据
@ModelAttribute放在类方法上面则表示该Action类中的每个请求调用之前都会执行该方法,因此在此方法里面可以做一些请求预处理,利用此特性就可以抽象出一个基本Action类,然后所有的Action类都继承自这个基本Aciton类,在基本Action类里面获取相应的request、response、session对象:
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public class BaseAction{
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protected HttpServletRequest request;
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protected HttpServletResponse response;
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protected HttpSession session;
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@ModelAttribute
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public void setReqAndRes(HttpServletRequest request, HttpServletResponse response){
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this.request = request;
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this.response = response;
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this.session = request.getSession();
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}
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/** 其他业务代码 */
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}
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2、通过spring提供的RequestContextHolder在非contrller层获取request和response对象
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HttpServletRequest request = ((ServletRequestAttributes)RequestContextHolder.getRequestAttributes()).getRequest();
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HttpServletResponse response = ((ServletRequestAttributes)RequestContextHolder.getRequestAttributes()).getResponse();
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HttpServletResponse response = ((ServletWebRequest)RequestContextHolder.getRequestAttributes()).getResponse();
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ServletContext context = ContextLoader.getCurrentWebApplicationContext().getServletContext();