SpringMVC获取request的方式

SpringMVC获取request的方式有哪些？小编来告诉大家。

1.最简单的方式(注解法)

@Autowired
private  HttpServletRequest request;

2.最麻烦的方法

(1)在web.xml中配置一个监听

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

(2)之后在程序里可以用

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

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
    }

3.最直接的方法

public String hello(HttpServletRequest request,HttpServletResponse response) 

通过以上介绍相信大家对SpringMVC获取request的方式已经有所了解，大家如果想了解更多相关知识，不妨来关注一下极悦的Java极悦在线学习，里面的课程内容丰富，从入门到精通，很适合零基础的小伙伴学习，希望对大家能够有所帮助。