SpringMVC ServletRequestAttributes的應用

在SpringMVC的源代碼中提供了一個封裝過的ThreadLocal，其中保存了每次請求的HttpServletRequest對象，（詳細請看org.springframework.web.context.request.ServletRequestAttributes的源代碼） 。

這樣我們就可以進行簡單封裝一下寫一個工具進行使用：

import lombok.extern.slf4j.Slf4j;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.context.request.RequestAttributes;
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;


@Slf4j
public class RequestHolder {

    /**
     * 獲取request
     *
     * @return HttpServletRequest
     */
    public static HttpServletRequest getRequest() {
        log.debug("getRequest -- Thread id :{}, name : {}", Thread.currentThread().getId(), Thread.currentThread().getName());
        ServletRequestAttributes servletRequestAttributes = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes());
        if (null == servletRequestAttributes) {
            return null;
        }
        return servletRequestAttributes.getRequest();
    }

    /**
     * 獲取Response
     *
     * @return HttpServletRequest
     */
    public static HttpServletResponse getResponse() {
        log.debug("getResponse -- Thread id :{}, name : {}", Thread.currentThread().getId(), Thread.currentThread().getName());
        ServletRequestAttributes servletRequestAttributes = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes());
        if (null == servletRequestAttributes) {
            return null;
        }
        return servletRequestAttributes.getResponse();
    }

    /**
     * 獲取session
     *
     * @return HttpSession
     */
    public static HttpSession getSession() {
        log.debug("getSession -- Thread id :{}, name : {}", Thread.currentThread().getId(), Thread.currentThread().getName());
        HttpServletRequest request = null;
        if (null == (request = getRequest())) {
            return null;
        }
        return request.getSession();
    }

    /**
     * 獲取session的Attribute
     *
     * @param name session的key
     * @return Object
     */
    public static Object getSession(String name) {
        log.debug("getSession -- Thread id :{}, name : {}", Thread.currentThread().getId(), Thread.currentThread().getName());
        ServletRequestAttributes servletRequestAttributes = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes());
        if (null == servletRequestAttributes) {
            return null;
        }
        return servletRequestAttributes.getAttribute(name, RequestAttributes.SCOPE_SESSION);
    }

    /**
     * 添加session
     *
     * @param name
     * @param value
     */
    public static void setSession(String name, Object value) {
        log.debug("setSession -- Thread id :{}, name : {}", Thread.currentThread().getId(), Thread.currentThread().getName());
        ServletRequestAttributes servletRequestAttributes = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes());
        if (null == servletRequestAttributes) {
            return;
        }
        servletRequestAttributes.setAttribute(name, value, RequestAttributes.SCOPE_SESSION);
    }

    /**
     * 清除指定session
     *
     * @param name
     * @return void
     */
    public static void removeSession(String name) {
        log.debug("removeSession -- Thread id :{}, name : {}", Thread.currentThread().getId(), Thread.currentThread().getName());
        ServletRequestAttributes servletRequestAttributes = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes());
        if (null == servletRequestAttributes) {
            return;
        }
        servletRequestAttributes.removeAttribute(name, RequestAttributes.SCOPE_SESSION);
    }

    /**
     * 獲取所有session key
     *
     * @return String[]
     */
    public static String[] getSessionKeys() {
        log.debug("getSessionKeys -- Thread id :{}, name : {}", Thread.currentThread().getId(), Thread.currentThread().getName());
        ServletRequestAttributes servletRequestAttributes = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes());
        if (null == servletRequestAttributes) {
            return null;
        }
        return servletRequestAttributes.getAttributeNames(RequestAttributes.SCOPE_SESSION);
    }
}