java - 参数 redirectattributes 是模型或映射类型，但不能从实际模型分配

Question

我在 Controller 中的请求处理方法中添加 RedirectAttributes 时遇到此异常 -

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.web.bind.annotation.support.HandlerMethodInvocationException: Failed to invoke handler method [public java.lang.String com.vc.teacher.controller.AccountController.signUpUser(com.vc.teacher.entities.User,org.springframework.web.servlet.mvc.support.RedirectAttributes)]; nested exception is java.lang.IllegalStateException: Argument [RedirectAttributes] is of type Model or Map but is not assignable from the actual model. You may need to switch newer MVC infrastructure classes to use this argument.
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:978)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:868)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:754)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
root cause

org.springframework.web.bind.annotation.support.HandlerMethodInvocationException: Failed to invoke handler method [public java.lang.String com.vc.teacher.controller.AccountController.signUpUser(com.vc.teacher.entities.User,org.springframework.web.servlet.mvc.support.RedirectAttributes)]; nested exception is java.lang.IllegalStateException: Argument [RedirectAttributes] is of type Model or Map but is not assignable from the actual model. You may need to switch newer MVC infrastructure classes to use this argument.
    org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:182)
    org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:446)
    org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:434)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:868)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:754)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
root cause

java.lang.IllegalStateException: Argument [RedirectAttributes] is of type Model or Map but is not assignable from the actual model. You may need to switch newer MVC infrastructure classes to use this argument.
    org.springframework.web.bind.annotation.support.HandlerMethodInvoker.resolveHandlerArguments(HandlerMethodInvoker.java:326)
    org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:172)
    org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:446)
    org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:434)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:868)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:754)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:847)

我的 bean-config 文件是 -

<?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:aop="http://www.springframework.org/schema/aop"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-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/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd">


    <mvc:annotation-driven />
    <context:component-scan base-package="com.vc.teacher" />


    <bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="annotatedClasses">
            <list>
                <value>com.vc.teacher.entities.User</value>
            </list>
        </property>
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect">org.hibernate.dialect.HSQLDialect</prop>
                <prop key="hibernate.current_session_context_class">thread</prop>
                <prop key="show_sql">true</prop>
            </props>
        </property>
    </bean>



    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql://localhost:3306/teacher"></property>
        <property name="username" value="root"></property>
        <property name="password" value="root"></property>
    </bean>

    <bean id="userDao" class="com.vc.teacher.db.dao.UserDao">
        <property name="sessionFactory" ref="sessionFactory"></property>
    </bean>


</beans>  

我的 Controller 是 -

package com.vc.teacher.controller;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.stereotype.Controller;
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;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;

import com.vc.teacher.db.dao.UserDao;
import com.vc.teacher.entities.User;

@Controller
public class AccountController {

    @RequestMapping("/login")
    public ModelAndView loginUser(@RequestParam("email") String email,
            @RequestParam("password") String password) {
        ApplicationContext context = new ClassPathXmlApplicationContext(
                "applicationContext.xml");
        User user = ((UserDao) context.getBean("userDao")).checkCreditionals(
                email, password);
        if (user != null)
            return new ModelAndView("jsp/result", "message",
                    "successfully login with user = " + email);
        else
            return new ModelAndView("jsp/index", "message", "invalid login");
    }

    @RequestMapping("/signUp")
    public String initilize(Model model) {
        model.addAttribute(new User());
        return "jsp/signup";
    }

    @RequestMapping(method=RequestMethod.POST,value="/register")
    public String signUpUser(User user,RedirectAttributes attributes) {
        boolean result = false;

        ApplicationContext context = new ClassPathXmlApplicationContext(
                "applicationContext.xml");
        result = ((UserDao)context.getBean("userDao")).registerUser(user);



        if (result == true){
            attributes.addFlashAttribute("message",
                    "You are ready to go now !");
            return "redirect:/signUp";
        } else{ 
            attributes.addFlashAttribute("message",
                    "Something went wrong");
                return "redirect:/signUp";
            }


    }
}

我的 spring-servlet.xml 文件是 -

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="
         http://www.springframework.org/schema/beans
         http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
         http://www.springframework.org/schema/context
         http://www.springframework.org/schema/context/spring-context-4.0.xsd
         http://www.springframework.org/schema/tx
         http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
         http://www.springframework.org/schema/aop
         http://www.springframework.org/schema/aop/spring-aop-4.0.xsd">

<context:component-scan base-package="com.vc.teacher.controller" />

<!-- Configuration defining views files -->

<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix">
            <value>/</value>
        </property>
        <property name="suffix">
            <value>.jsp</value>
        </property>
</bean>

</beans>

我想在重定向请求中添加属性。为此，我正在使用 RedirectAttributes 类。但是在我的方法参数中添加它的对象之后，我的方法没有被调用。我正在使用 spring 4.1.6。

Answer 1

移动

<mvc:annotation-driven />

到您的 servlet 上下文配置。由于它不存在，Spring 的 DispatcherServlet 使用其默认配置，该配置使用已弃用的 AnnotationMethodHandlerAdapter 而不是更复杂的 RequestMappingHandlerAdapter。

此外，

<context:component-scan base-package="com.vc.teacher" />

是

的超集

<context:component-scan base-package="com.vc.teacher.controller" />

因此，对于 com.vc.teacher.controller 下的任何 bean，您都会有重复的 bean 定义。通过使您的组件扫描不同来解决这个问题。