两种方法

1、request.getSession().getAttribute("X") 2、${sessionScope.X}

九大内置对象

JSP中有九大内置对象，可以直接用session，也可以获取从request中取，其本质都是同一个。九大内置对象如下：

JSP中九大内置对象为：

内置对象	说明	类型	作用域
request	请求对象	javax.servlet.ServletRequest	Request
response	响应对象	javax.servlet.SrvletResponse	Page
pageContext	页面上下文对象	javax.servlet.jsp.PageContext	Page
session	会话对象	javax.servlet.http.HttpSession	Session
application	应用程序对象	javax.servlet.ServletContext	Application
out	输出对象	javax.servlet.jsp.JspWriter	Page
config	配置对象	javax.servlet.ServletConfig	Page
page	页面对象	javax.lang.Object	Page
exception	异常对象	javax.lang.Throwable	page

代码实例

jsp

<button type="button" class="username dropdown-toggle" data-toggle="dropdown" aria-expanded="false">
                        ${sessionScope.currentUser.username}<span class="caret"></span>
 </button>

java

package com.restfeel.controller

import org.slf4j.LoggerFactory
import org.springframework.beans.factory.annotation.Value
import org.springframework.security.core.context.SecurityContextHolder
import org.springframework.security.core.userdetails.UserDetails
import org.springframework.stereotype.Controller
import org.springframework.web.bind.annotation.RequestMapping
import org.springframework.web.bind.annotation.RequestMethod
import java.util.*
import javax.servlet.http.HttpServletRequest
import javax.servlet.http.HttpServletResponse

/**
 * Created by jack on 2017/3/30.
 */

@Controller
class HomeController {
    internal var logger = LoggerFactory.getLogger(AppController::class.java)

    @Value("${application.message:REST Feel}")
    private val message = "REST Feel"

    @RequestMapping("/")
    fun home(model: MutableMap<String, Any>, request: HttpServletRequest, response: HttpServletResponse): String {
        model.put("time", Date())
        model.put("message", this.message)
        val authentication = SecurityContextHolder.getContext().authentication
        val currentUser  =if (authentication == null) null!! else authentication.principal as UserDetails
        model.put("currentUser", currentUser)

        // put currentUser into session
        request.getSession().setAttribute("currentUser",currentUser)
        return "jsp/home"
    }
}

源代码工程：

https://github.com/Jason-Chen-2017/restfeel

《JSP极简教程》在jsp页面获取session对象两种方法九大内置对象代码实例

两种方法

九大内置对象

代码实例