SpringMVC向域*享数据

SpringMVC向域*享数据

向request域*享数据

  • 通过原生Servlet方法
  • 通过ModelAndView
  • 通过Model
  • 通过Map
  • 通过ModelMap
index.html

<body>
<h1>This is index.html</h1>
<a th:href="@{/testRequestAPI}">使用RequestAPI向request域中传值</a><br>
<a th:href="@{/modelAndView}">使用modelAndView向request域中传值</a><br>
<a th:href="@{/model}">使用model向request域中传值</a><br>
<a th:href="@{/map}">使用map向request域中传值</a><br>
<a th:href="@{/modelMap}">使用modelMap向request域中传值</a><br>
</body>

success.html

<body>
<h2>success</h2>
<br>
<p th:text="${requestScope}"></p>
</body>
@Controller
public class ScopeController {
    @RequestMapping("/testRequestAPI")
    public String testRequestAPI(HttpServletRequest request){
        request.setAttribute("requestScope","hello,RequestAPI");
        return "success";
    }

    @RequestMapping("/modelAndView")
    public ModelAndView testModelAndView(){
        ModelAndView mav = new ModelAndView();
        mav.setViewName("success");
        mav.addObject("requestScope","hello,session");
        return mav;
    }

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

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

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

以上五种方式,都可以讲数据传输到request域中

model,map,modelMap的关系

我们在三个方法中分别加入一段输出全路径,结果都为org.springframework.validation.support.BindingAwareModelMap,可以得知三者的参数其实本质上都是 BindingAwareModelMap 类型的

    @RequestMapping("/model")
    public String testModel(Model model){
        model.addAttribute("requestScope","hello,model");
        System.out.println(model.getClass().getName());
        return "success";
    }

    @RequestMapping("/map")
    public String testMap(Map<String,Object> map){
        map.put("requestScope","hello,map");
        System.out.println(map.getClass().getName());
        return "success";
    }

    @RequestMapping("/modelMap")
    public String testMap(ModelMap modelMap){
        modelMap.addAttribute("requestScope","hello,modelMap");
        System.out.println(modelMap.getClass().getName());
        return "success";
    }

我们来看一下BindingAwareModelMap的结构

SpringMVC向域*享数据

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

五个方法中,不论用哪种方法实现向域中传输数据,最后都是封装成ModelAndView对象来传递

无论哪种方法,都会经过前端控制器,前端控制器中有一个doDispatch方法,里面都会将这些值封装成一个ModelAndView对象

SpringMVC向域*享数据

向Session、Application域中传值

SpringMVC提供了注解方法来设置Session域中的值,但不如原生request方法来的简单,而像application域中传值,只需要调用Session即可

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

    @RequestMapping("/application")
    public String testApplication(HttpSession session){
        ServletContext application = session.getServletContext();
        application.setAttribute("requestScope","hello,application");
        return "success";
    }
<body>
<h2>success</h2>
<br>
<p th:text="${requestScope}"></p>
<!--输出Session域中的requestScope值-->
<p th:text="${session.requestScope}"></p>
<!--输出application域中的requestScope值-->
<p th:text="${application.requestScope}"></p>
</body>
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