spring几种获取 HttpServletRequest 对象的方式

以下的 request 实例都编号了，一共 4 种 方式

1.@Autowired 方式
2.public void Test(HttpServletRequest request1, HttpServletResponse resp,HttpSession session1) 方式
3.((ServletRequestAttributes)RequestContextHolder.getRequestAttributes()).getRequest(); 方式
4.Global.getHttpServletRequest(); 方式，该方式基于 第三种做的封装

方法4 最灵活，不需要每个 action 中都定义 HttpServletRequest 参数。

LoginController.java

@Controller
@RequestMapping("/demo")
public class LoginController{
    @Autowired
    private  HttpServletRequest request2;  

    @RequestMapping("test")
    @ResponseBody
    public void Test(HttpServletRequest request1, HttpServletResponse resp,HttpSession session1){
        resp.setCharacterEncoding("UTF=8");
        resp.setContentType("text/html;charset=UTF-8");  

        String key = "test_date";
        HttpSession session = request1.getSession();
        session.setAttribute(key, new Date());
        String sessionId = session.getId();
        Date time = (Date)session.getAttribute(key);  

        HttpServletRequest request3 = ((ServletRequestAttributes)RequestContextHolder.getRequestAttributes()).getRequest();
        HttpServletRequest request4 = Global.getHttpServletRequest();  

        //判断session是不是新创建的
        try {
            if (session.isNew()) {
                    resp.getWriter().print(java.text.MessageFormat.format(
                            "【{0}】session创建成功，session的id是：</br>{1}</br>{2}</br>{3}</br>{4}</br>{5}"
                            , StringExtend.getString(time)
                            , sessionId
                            , session1.getId()
                            , request2.getSession().getId()
                            , request3.getSession().getId()
                            , request4.getSession().getId()));  

            }else {
                resp.getWriter().print(java.text.MessageFormat.format(
                        "【{0}】服务器已经存在该session了，session的id是：</br>{1}</br>{2}</br>{3}</br>{4}</br>{5}"
                            , StringExtend.getString(time)
                            , sessionId
                            , session1.getId()
                            , request2.getSession().getId()
                            , request3.getSession().getId()
                            , request4.getSession().getId()));
            }
        } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
        }
    }  

Global.java

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;  

import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;  

/**
* 使用该类必须在 web.xml 中添加监听（org.springframework.web.context.request.RequestContextListener）
* 该作用域仅适用于WebApplicationContext环境
*/
public class Global {
    static String _loginSessionKey="login_session";
    /**
     * 获取当前请求session
     * @return
     */
    public static HttpServletRequest getHttpServletRequest(){
        HttpServletRequest request = ((ServletRequestAttributes)RequestContextHolder
                .getRequestAttributes())
                .getRequest();
        return request;
    }
    /**
     * 获取当前请求session
     * @return
     */
    public static HttpSession getHttpSession(){
        return getHttpServletRequest().getSession();
    }
}  

web.xml 加入监听

<!-- 5. spring 注册监听，获取上下文中的 HttpServletRequest 对象（对 Global 支持）  -->

1. <listener>
2. <listener-class>
3. org.springframework.web.context.request.RequestContextListener
4. </listener-class>
5. </listener>

https://blog.csdn.net/hellozhxy/article/details/80775832