Spring MVC 向页面传值-Map、Model、ModelMap、ModelAndView
-
Spring MVC 向页面传值,有4种方式:
ModelAndView
Map
Model
ModelMap -
使用后面3种方式,都是在方法参数中,指定一个该类型的参数。
-
Model
Model 是一个接口, 其实现类为ExtendedModelMap,继承了ModelMap类。
public class ExtendedModelMap extends ModelMap implements Model
- ModelMap
ModelMap的声明格式:
public class ModelMap extends LinkedHashMap<String, Object>
- ModelMap或者Model通过addAttribute方法向页面传递参数,其中addAttribute方法参数有多种方式:
public ModelMap addAttribute(String attributeName, Object attributeValue){...}
public ModelMap addAttribute(Object attributeValue){...}
public ModelMap addAllAttributes(Collection<?> attributeValues) {...}
public ModelMap addAllAttributes(Map<String, ?> attributes){...}
- 一个例子:
Java代码:
@RequestMapping("/test")
public String test(Map<String,Object> map,Model model,ModelMap modelMap){
map.put("names", Arrays.asList("john","tom","jeff"));
model.addAttribute("time", new Date());
modelMap.addAttribute("city", "beijing");
modelMap.put("gender", "male");
return "hello";
}
jsp 页面:
1、time:${requestScope.time}<br/>
2、names:${requestScope.names }<br/>
3、city:${requestScope.city }<br/>
4、gender:${requestScope.gender }
结果:
1、time:Sun Mar 08 16:35:58 CST 2017
2、names:[john, tom, jeff]
3、city:beijing
4、gender:male
- ModelAndView 例子:
@RequestMapping(value = "/mergeModel")
public ModelAndView mergeModel(Model model) {
model.addAttribute("a", "a"); //① 添加模型数据
ModelAndView mv = new ModelAndView("success");
mv.addObject("a", "update"); //② 在视图渲染之前更新③处同名模型数据
model.addAttribute("a", "new"); //③ 修改①处同名模型数据
//视图页面的a将显示为"update" 而不是"new"
return mv;
}