spring MVC要注意的地方：
控制器代码如下：
package com.mvc.jn.controller;
import java.util.Map;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;
@org.springframework.stereotype.Controller
public class HelloWorldController {
// http://localhost:8088/springMVCannotations/hello2
@RequestMapping(value = "/hello2", method = RequestMethod.GET)
public String sayHello2(
@RequestParam(value = "name", required = false) String username,
Map map) {
map.put("message1", username);
System.out.println("my name:" + username);
return "hello22";
}
// http://localhost:8088/springMVCannotations/hello3
@RequestMapping(value = "/hello3", method = RequestMethod.GET)
public ModelAndView sayHello3(
@RequestParam(value = "name", required = false) String username) {
System.out.println("my name:" + username);
ModelAndView mav = new ModelAndView("hello33");
mav.getModel().put("message1", username);
return mav;
}
// http://localhost:8088/springMVCannotations/hello44?name=whuang
@RequestMapping(value = "/hello44", method = RequestMethod.GET)
// 与网上说的不一致，网上说方法名就是试图
public Model hello4(
@RequestParam(value = "name", required = false) String username,
Model model) {
System.out.println("my name:" + username);
model.addAttribute("message1", username);
return model;
}
@RequestMapping(value = "/hello555", method = RequestMethod.GET)
public Model hello5(String username, Model model) {
System.out.println("my name:" + username);
model.addAttribute("message1", username);
return model;
}
}
ViewResolver配置如下：
问题1：调用控制器中的hello4 方法后会返回那个视图？
按照网上的说法，会返回“hello4”（方法名），如下图
但是经过我反复测试，发现它返回的视图是“hello44”，即@RequestMapping 指定的value。
问题2：访问方法hello5时，必须传参数username 吗？
答：不是必须的。
什么情况下是必须的呢?
当有注解@RequestParam(value = "username")时才是必须的,若不传该参数将报错.
url 是“http://localhost:8088/springMVCannotations/hello555?username=ccc”时，会自动设置username的值
问题3：spring MVC与hibernate4集成时报错：No Session found for current thread
详情请参阅我的另一篇博客：http://hw1287789687.iteye.com/blog/1949852
问题4：启动tomcat时报错：java.lang.ClassNotFoundException: org.springframework.web.servlet.DispatcherServlet
原因是：pom.xml中缺少：
org.springframework spring-web 3.2.3.RELEASE org.springframework spring-webmvc 3.2.3.RELEASE
问题5：spring MVC 使用bean接收参数时如何传参?
比如查询时,controller 把参数注入到bean中,
@RequestMapping(value = "/show")
public String show(Model model,User user,UserView view,HttpSession session) throws CloneNotSupportedException {
if(!ValueWidget.isNullOrEmpty(view.getPageFlag())&&view.getPageFlag().equals(Constant2.PAGEFLAG_NOT_QUERY)){
System.out.println("不是查询");
user=(User)session.getAttribute("user2");
try {
BeanUtils.copyProperties(view, user);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}else{//查询
System.out.println("是查询");
session.setAttribute("user2", user);
}
PageAssistant.paging(user,true,view, userDao);
model.addAttribute("view", view);
model.addAttribute("currentTime", TimeHWUtil.getCurrentTimestamp().getTime());
return "user/show";
}
方法show()的参数user会保存请求要素,那么在页面上是如何编写表单控件name的呢?
上述代码是不对的,应该是:
username" value="${view.username }" />
name" value="${view.name }" />
注意:spring MVC 的依赖注入与struts2 是不同的.
spring MVC 的学习资料见附件spring MVC学习笔记.zip
Controller 中Action 参数
, User user, 和
, @RequestParam(required = false) User user,
是有区别的.
如果包含@RequestParam ,则无法自动注入对象的成员变量
