获取request，获取response，获取session，获取ServletRequestAttributes，的工具类

在Spring框架中，你可以使用RequestContextHolder来获取当前的HttpServletRequest, HttpServletResponse 和 ServletRequestAttributes。以下是一个工具类的示例代码：

import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
 
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
 
public class WebUtils {
 
    public static HttpServletRequest getCurrentRequest() {
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        return attributes == null ? null : attributes.getRequest();
    }
 
    public static HttpServletResponse getCurrentResponse() {
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        return attributes == null ? null : attributes.getResponse();
    }
 
    public static HttpSession getCurrentSession() {
        return getCurrentRequest().getSession();
    }
 
    public static ServletRequestAttributes getServletRequestAttributes() {
        return (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
    }
}

使用这个工具类，你可以在任何需要的地方获取到当前请求的HttpServletRequest, HttpServletResponse 和 HttpSession。注意，在非web请求的线程中（例如定时任务）使用这些方法可能返回null。