org.springframework.web.bind.ServletRequestDataBinder 无法转换为 org.springframework.web.bind.support.WebRequestDataBinder

Question

我刚刚开始阅读 spring。我收到 org.springframework.web.bind.ServletRequestDataBinder cannot be cast to org.springframework.web.bind.support.WebRequestDataBinder 问题。

异常

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.ClassCastException: org.springframework.web.bind.ServletRequestDataBinder cannot be cast to org.springframework.web.bind.support.WebRequestDataBinder
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:625)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:536)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

根本原因

java.lang.ClassCastException: org.springframework.web.bind.ServletRequestDataBinder cannot be cast to org.springframework.web.bind.support.WebRequestDataBinder
    org.springframework.web.bind.annotation.support.HandlerMethodInvoker.doBind(HandlerMethodInvoker.java:754)
    org.springframework.web.bind.annotation.support.HandlerMethodInvoker.doBind(HandlerMethodInvoker.java:744)
    org.springframework.web.bind.annotation.support.HandlerMethodInvoker.resolveHandlerArguments(HandlerMethodInvoker.java:296)
    org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:163)
    org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:354)
    org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:342)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:763)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:709)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:613)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:536)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

这是代码

学生豆

public class Student {
    private int age,id;
    private String name;
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}

学生控制器

import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class StudentController {
    @RequestMapping(value="/student",method=RequestMethod.GET)
    public ModelAndView student(){
        return new ModelAndView("student","command",new Student());  // (view name, logical name to access in view, object model)
    }

    @RequestMapping(value="/addstudent",method=RequestMethod.POST)
    public String addStudent(@ModelAttribute("Student")Student student,ModelMap model){
        model.addAttribute("name",student.getName());
        model.addAttribute("age",student.getAge());
        model.addAttribute("id",student.getId());

        return "result";
    }
}

Student.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>

<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Spring MVC form Handling</title>
</head>
<body>
    <h2>Student Information</h2>

    <form:form method="POST" action="/SpringFormHandling/addstudent">
        <table>
            <tr>
                <td><form:label path="name">Name</form:label></td>
                <td><form:input path="name" /></td>
            </tr>
            <tr>
                <td><form:label path="age">Age</form:label></td>
                <td><form:input path="age" /></td>
            </tr>
            <tr>
                <td><form:label path="id">Id</form:label></td>
                <td><form:input path="id" /></td>
            </tr>
            <tr>
                <td colspan="2"><input type="submit" value="Submit" /></td>
            </tr>
        </table>

    </form:form>

</body>
</html>

当我尝试 localhost:8080/MyApp/student 时，student.jsp 页面被返回并且在提交表单后它应该重定向到 result.jsp 并显示相同的填充数据但是当我提交表单时，它抛出 ClassCastException.I 已经尝试了很多但没有得到任何线索。有完整的例子 https://www.tutorialspoint.com/spring/spring_mvc_form_handling_example.htm

Answer 1

当您在 class 路径上有多个相同 class 的版本时，通常会发生这种情况（例如，我在使用 Apache Tiles 时遇到了这样的问题，它添加了一些旧版本的 Spring MVC).

检查您的 webapp lib 文件夹中有哪些 jar 是个好主意。或者，使用 IDE，例如 Eclipse，您可以显示 "Open Type" 对话框并键入 class' 名称，如果存在多个版本，它将显示它们。

org.springframework.web.bind.ServletRequestDataBinder 无法转换为 org.springframework.web.bind.support.WebRequestDataBinder

org.springframework.web.bind.ServletRequestDataBinder cannot be cast to org.springframework.web.bind.support.WebRequestDataBinder

spring

spring-mvc

classcastexception