是的,我阅读这是很常见的问题,但是阅读这些帖子并没有真正帮助我。
在 简短的故事 是,我想提交一份关于showAllComments.jsp形式
<form:form method="post" action="postNewComment.html"> <table> <tr> <td><form:label path="comment"> COMMENT </form:label></td> <td><form:input path="comment" /></td> </tr> <tr> <td colspan="2"><input type="submit" value="WRITE" /></td> </tr> </table> </form:form>
这是控制器:
@Controller @SessionAttributes public class CommentController { @Autowired private CommentService commentService; @RequestMapping(value = "/postNewComment", method = RequestMethod.POST) public ModelAndView showAllUsers(@ModelAttribute("command") Comment comment, BindingResult result) { System.out.println(comment.getComment()); Map<String, Object> model = new HashMap<String, Object>(); model.put("COMMENTS", commentService.getComments()); return new ModelAndView("showAllComments", model); } }
结果是: java.lang.IllegalStateException:BeanResult’command’的BindingResult和普通目标对象都不能用作请求属性
但可能您需要从头开始了解 整个故事 :用户通过单击以下内容在index.jsp上启动应用程序
<a href="toLoginPage.html">Log in</a>
该链接将他带到LoginController
@RequestMapping("/toLoginPage") public ModelAndView goToLoginPage() { return new ModelAndView("login", "command", new User()); }
然后,他被带到login.jsp,其中提供了用户名和密码。
<form:form method="post" action="log_in.html"> <input type="text" name="uName" /> <input type="password" name="pW" /> <input type="submit" value="Log IN"> </form:form>
他提交了表单,然后将其带回LoginController
@RequestMapping(value = "/log_in", method = RequestMethod.POST) public ModelAndView tryToLogin(@RequestParam("uName") String uName, @RequestParam("pW") String pW, HttpServletResponse response, HttpServletRequest request) { ModelAndView ret = new ModelAndView("login", "command", new User()); User user = userService.existingUser(uName, pW); loggedInUser = new User(); if (user != null) { Map<String, Object> model = new HashMap<String, Object>(); model.put("COMMENTS", allComments); model.put("LOGGED_IN_USER", loggedInUser); ret = ModelAndView("showAllComments", model); } return ret; }
成功登录后,他将进入showAllComments页面,在那里他可以看到所有评论,并且他应该能够添加自己的评论,但是提交上述表格将引发上述异常。我觉得有些东西丢失了,但我不知道是什么。仅作记录,我显示了web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5"> <display-name>Spring3MVC</display-name> <servlet> <servlet-name>spring</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>spring</servlet-name> <url-pattern>*.html</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app>
和spring-servlet.xml
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd"> <context:property-placeholder location="classpath:jdbc.properties" /> <context:component-scan base-package="net" /> <tx:annotation-driven transaction-manager="hibernateTransactionManager" /> <bean id="viewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver"> <property name="viewClass" value="org.springframework.web.servlet.view.JstlView" /> <property name="prefix" value="/WEB-INF/jsp/" /> <property name="suffix" value=".jsp" /> </bean> <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> <property name="driverClassName" value="${database.driver}" /> <property name="url" value="${database.url}" /> <property name="username" value="${database.user}" /> <property name="password" value="${database.password}" /> </bean> <bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean"> <property name="dataSource" ref="dataSource" /> <property name="annotatedClasses"> <list> <value>net.model.User</value> <value>net.model.Comment</value> </list> </property> <property name="hibernateProperties"> <props> <prop key="hibernate.dialect">${hibernate.dialect}</prop> <prop key="hibernate.show_sql">${hibernate.show_sql}</prop> </props> </property> </bean> <bean id="hibernateTransactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager"> <property name="sessionFactory" ref="sessionFactory" /> </bean> <bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource"> <property name="basename" value="classpath:messages" /> <property name="defaultEncoding" value="UTF-8" /> </bean> <bean id="localeChangeInterceptor" class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor"> <property name="paramName" value="lang" /> </bean> <bean id="localeResolver" class="org.springframework.web.servlet.i18n.CookieLocaleResolver"> <property name="defaultLocale" value="en" /> </bean> <bean id="handlerMapping" class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping"> <property name="interceptors"> <ref bean="localeChangeInterceptor" /> </property> </bean> </beans>
当您在logincontroller中显示showAllComments.jsp时,您需要添加一个表单bean类(即Comment)作为模型的属性。
@RequestMapping(value = "/log_in", method = RequestMethod.POST) public ModelAndView tryToLogin(@RequestParam("uName") String uName, @RequestParam("pW") String pW, HttpServletResponse response, HttpServletRequest request) { ModelAndView ret = new ModelAndView("login", "command", new User()); User user = userService.existingUser(uName, pW); loggedInUser = new User(); model.addAttribute("command", new Comment()); if (user != null) { Map<String, Object> model = new HashMap<String, Object>(); model.put("COMMENTS", allComments); model.put("LOGGED_IN_USER", loggedInUser); ret = ModelAndView("showAllComments", model); } return ret; }
这应该工作正常。
更新
使用“命令”作为命令对象名称不是一个好习惯。对于班级注释,您可以使用“注释”或类似的内容。如果这样做,请使用以下代码更新表单。
<form:form method="post" action="postNewComment.html" commandName="comment"> <table> <tr> <td><form:label path="comment"> COMMENT </form:label></td> <td><form:input path="comment" /></td> </tr> <tr> <td colspan="2"><input type="submit" value="WRITE" /></td> </tr> </table> </form:form>
在所有其他地方进行相同的更改,即
model.addAttribute("comment", new Comment());
和
@ModelAttribute("comment")
更新2
@RequestMapping(value="userRegistration", method = RequestMethod.GET) public ModelAndView showUserRegistrationForm(Model model){ model.addAttribute("user", new AccountDetailsForm()); return new ModelAndView("userRegistration"); }