1、使用ServletAPI向request域对象共享数据

@RequestMapping("/testServletAPI")
public String testServletAPI(HttpServletRequest request){
request.setAttribute("testScope", "hello,servletAPI");
return "success";
}

<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<p th:text{textScope}></p>
</body>

直接在大括号里面加上request中的键

2、使用ModelAndView向request域对象共享数据

@RequestMapping("/testModelAndView")
public ModelAndView testModelAndView(){
/**
* ModelAndView有Model和View的功能
* Model主要用于向请求域共享数据
* View主要用于设置视图，实现页面跳转
*/
ModelAndView mav = new ModelAndView();
//向请求域共享数据
mav.addObject("testScope", "hello,ModelAndView");
//设置视图，实现页面跳转
mav.setViewName("success");
return mav;
}

<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<p th:text{textScope}></p>
</body>

注：如果使用了ModelAndView，方法返回值必须是ModelAndView，它需要返回让前端控制器解析

3、使用Model向request域对象共享数据

@RequestMapping("/testModel")
public String testModel(Model model){
model.addAttribute("testScope", "hello,Model");
return "success";
}

<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<p th:text{textScope}></p>
</body>

4、使用map向request域对象共享数据

@RequestMapping("/testMap")
public String testMap(Map<String, Object> map){
map.put("testScope", "hello,Map");
return "success";
}

注：声明的map必须放在形参中?

5、使用ModelMap向request域对象共享数据

@RequestMapping("/testModelMap")
public String testModelMap(ModelMap modelMap){
modelMap.addAttribute("testScope", "hello,ModelMap");
return "success";
}

注：声明的ModelMap必须放在形参中?

6、Model、ModelMap、Map的关系

Model、ModelMap、Map类型的参数其实本质上都是 BindingAwareModelMap 类型的

public interface Model{}
public class ModelMap extends LinkedHashMap<String, Object> {}
public class ExtendedModelMap extends ModelMap implements Model {}
public class BindingAwareModelMap extends ExtendedModelMap {}

?以上六种方式，最终都会封装成ModelAndView

7、向session域共享数据

@RequestMapping("/testSession")
public String testSession(HttpSession session){
session.setAttribute("testSessionScope", "hello,session");
return "success";
}

8、向application域共享数据

@RequestMapping("/testApplication")
public String testApplication(HttpSession session){
ServletContext application = session.getServletContext();
application.setAttribute("testApplicationScope", "hello,application");
return "success";
}