spring boot——请求与参数校验——spring-mvc-域对象共享数据——介绍一

 Spring MVC 中，控制器在接收到 DispatcherServlet 分发过来的请求后，会继续调用 Model 层对请求进行处理。Model 层处理完请求后的结果被称为模型数据，会将模型数据返回给 Controller。

Controller 在接收到 Model 层返回的模型数据后，下一步就是将模型数据通过域对象共享的方式传递给 View 视图进行渲染，最终返回给客户端展示。

 

 

 

域对象是服务器在内存上创建的一块存储空间，主要用不同动态资源之间的数据传递和数据共享。在 Spring MVC 中，常用的域对象有 request 域对象、session 域对象、application 域对象等。

 

 

 

Spring MVC 提供了多种域对象共享数据的方式，其中最常用的方式如下：

• 使用 Servlet API 向 request 域对象中共享数据
• 使用 ModelAndView 向 request 域对象中共享数据
• 使用 Model 向 request 域对象中共享数据
• 使用 Map 向 request 域对象中共享数据
• 使用 ModelMap 向 request 域对象中共享数据
• 使用 Servlet API 向 session 域中共享数据
• 使用 Servlet API 向 application 域中共享数据

下面我们就一一对这几种域对象共享数据的方式进行介绍。

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

之前笔记：https://www.cnblogs.com/xiaobaibailongma/p/17035102.html

 

 

 

package org.example.controller.requestparam;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

@RestController
public class ShareValueController {


    // http://localhost:8080/shareValue001


    /**
     * 域共享数据——request只在一次请求中有效，不能跨请求，转发过程也是一次请求，也是有效的
     * @param request
     * @return
     */
    @RequestMapping("/shareValue001")
    public String test1(HttpServletRequest request) {

        request.setAttribute("a","b");
        Object ac = request.getAttribute("a");
        System.out.println(ac);
        request.removeAttribute("a");

        Object acb = request.getAttribute("a");
        System.out.println(acb);

        return "cheng_gong";
    }






    @RequestMapping(value = "/shareValue002")
    public void test2(HttpServletRequest request, HttpServletResponse response)
    {

        HttpSession session = request.getSession();

        session.setAttribute("msg","session-hello");

    }


    @RequestMapping(value = "/shareValue003")
    public void test3(HttpServletRequest request,HttpServletResponse response)
    {

        HttpSession session = request.getSession();
        Object as = session.getAttribute("msg");
        System.out.println(as);

    }












}

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

之前笔记：https://www.cnblogs.com/xiaobaibailongma/p/17048145.html

package org.example.controller.requestparam;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

@RestController
public class ShareValueController {


    // http://localhost:8080/shareValue001


    /**
     * 域共享数据——request只在一次请求中有效，不能跨请求，转发过程也是一次请求，也是有效的
     * @param request
     * @return
     */
    @RequestMapping("/shareValue001")
    public String test1(HttpServletRequest request) {

        request.setAttribute("a","b");
        Object ac = request.getAttribute("a");
        System.out.println(ac);
        request.removeAttribute("a");

        Object acb = request.getAttribute("a");
        System.out.println(acb);

        return "cheng_gong";
    }






    @RequestMapping(value = "/shareValue002")
    public void test2(HttpServletRequest request, HttpServletResponse response)
    {

        HttpSession session = request.getSession();

        session.setAttribute("msg","session-hello");

    }


    @RequestMapping(value = "/shareValue003")
    public void test3(HttpServletRequest request,HttpServletResponse response)
    {

        HttpSession session = request.getSession();
        Object as = session.getAttribute("msg");
        System.out.println(as);

    }












}

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

笔记：https://www.cnblogs.com/xiaobaibailongma/p/17045120.html

 

 

 

 

 

package org.example.controller.requestparam;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

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

@RestController
public class ShareValueController {


    // http://localhost:8080/shareValue001


    /**
     * 域共享数据——request只在一次请求中有效，不能跨请求，转发过程也是一次请求，也是有效的
     * @param request
     * @return
     */
    @RequestMapping("/shareValue001")
    public String test1(HttpServletRequest request) {

        request.setAttribute("a","b");
        Object ac = request.getAttribute("a");
        System.out.println(ac);
        request.removeAttribute("a");

        Object acb = request.getAttribute("a");
        System.out.println(acb);

        return "cheng_gong";
    }






    @RequestMapping(value = "/shareValue002")
    public void test2(HttpServletRequest request, HttpServletResponse response)
    {

        HttpSession session = request.getSession();

        session.setAttribute("msg","session-hello");

    }


    @RequestMapping(value = "/shareValue003")
    public void test3(HttpServletRequest request,HttpServletResponse response)
    {

        HttpSession session = request.getSession();
        Object as = session.getAttribute("msg");
        System.out.println(as);

    }




    @RequestMapping(value = "/shareValue004")
    public void test4(HttpServletRequest request,HttpServletResponse response)
    {

        HttpSession session = request.getSession();
        ServletContext application = session.getServletContext();
        application.setAttribute("testApplicationScope", "hello,application");

    }



    @RequestMapping(value = "/shareValue005")
    public void test5(HttpServletRequest request,HttpServletResponse response)
    {

        HttpSession session = request.getSession();
        ServletContext application = session.getServletContext();
        Object ad = application.getAttribute("testApplicationScope");
        System.out.println(ad);


    }









}