-
Spring MVC 向頁面傳值,有4種方式:
ModelAndView
Map
Model
ModelMap
- 使用後面3種方式,都是在方法參數中,指定一個該類型的參數。
- Model 是一個接口, 其實作類為ExtendedModelMap,繼承了ModelMap類。
public class ExtendedModelMap extends ModelMap implements Model
- ModelMap的聲明格式:
public class ModelMap extends LinkedHashMap<String, Object>
- ModelMap或者Model通過addAttribute方法向頁面傳遞參數,其中addAttribute方法參數有多種方式:
public ModelMap addAttribute(String attributeName, Object attributeValue){...}
public ModelMap addAttribute(Object attributeValue){...}
public ModelMap addAllAttributes(Collection<?> attributeValues) {...}
public ModelMap addAllAttributes(Map<String, ?> attributes){...}
-
一個例子:
Java代碼:
@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";
}
1、time:${requestScope.time}<br/>
2、names:${requestScope.names }<br/>
3、city:${requestScope.city }<br/>
4、gender:${requestScope.gender }
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 添加模型資料
ModelAndView mv = new ModelAndView("success");
mv.addObject("a", "update"); //② 在視圖渲染之前更新③處同名模型資料
model.addAttribute("a", "new"); //③ 修改①處同名模型資料
//視圖頁面的a将顯示為"update" 而不是"new"
return mv;
}