Spring MVC Hibernate Error java.lang.Object;不能被轉換爲模型。員工

Question

我正在嘗試將hibernate與Spring集成。下面是代碼，

Employee.java

package java4s.model; 

import java.util.Date; 

import javax.validation.constraints.NotNull; 
import javax.validation.constraints.Pattern; 
import javax.validation.constraints.Size; 

import org.hibernate.validator.constraints.NotEmpty; 
import org.springframework.web.servlet.ModelAndView; 

public class Employee { 

    @NotEmpty 
    private String userid; 

    @Size(min = 3, max = 20) 
    private String firstname; 

    @Size(min = 3, max = 20) 
    private String lastname;  

    @NotEmpty 
    private String mobileno; 

    @NotEmpty 
    @Size(min = 3, max = 20) 
    private String username; 

    @NotEmpty 
    @Size(min = 3, max = 20) 
    private String password; 

    @NotEmpty 
    @Pattern(regexp = ".+@.+\\.[a-z]+") 
    private String email; 

    @NotNull 
    @NotEmpty 
    private String birthDate; 

    @NotEmpty 
    private String profession; 
    private String studenterrors; 

    public String getUserid() 
    { 
     return userid; 
    } 
    public void setUserid(String userid) 
    { 
     this.userid = userid; 
    } 

    public String getUsername() 
    { 
     return username; 
    } 
    public void setUsername(String username) 
    { 
     this.username = username; 
    } 
    public String getFirstname() 
    { 
     return firstname; 
    } 
    public void setFirstname(String firstname) 
    { 
     this.firstname = firstname; 
    } 
    public String getLastname() 
    { 
     return lastname; 
    } 
    public void setLastname(String lastname) 
    { 
     this.lastname = lastname; 
    } 
    public String getMobileno() 
    { 
     return mobileno; 
    } 
    public void setMobileno(String mobileno) 
    { 
     this.mobileno = mobileno; 
    } 

    public String getPassword() 
    { 
     return password; 
    } 
    public void setPassword(String password) 
    { 
     this.password = password; 
    } 
    public String getEmail() 
    { 
     return email; 
    } 
    public void setEmail(String email) 
    { 
     this.email = email; 
    } 
    public String getBirthdate() 
    { 
     return birthDate; 
    } 
    public void setBirthdate(String birthDate) 
    { 
     this.birthDate = birthDate; 
    } 
    public String getProfession() 
    { 
     return profession; 
    } 
    public void setProfession(String profession) 
    { 
     this.profession = profession; 
    } 
    public String getStudenterrors() 
    { 
     return studenterrors; 
    } 
    public void setStudenterrors(String studenterrors) 
    { 
     this.studenterrors = studenterrors; 
    } 
} 

EmployeeServiceImpl.java

@SuppressWarnings("unchecked") 
    @Override 
    public List<Employee> getUserinfo(String username) { 
     // TODO Auto-generated method stub 

     Configuration configuration = new Configuration(); 
     configuration.configure(); 

     ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings(configuration.getProperties()).buildServiceRegistry(); 
     SessionFactory sessionFactory = configuration.buildSessionFactory(serviceRegistry); 
     Session session = sessionFactory.openSession(); 
     session.beginTransaction(); 

     String sql_query = "SELECT username, firstname, lastname, emailid, profession, mobileno, to_char(birthdate, 'MM/DD/YYYY') AS birthdate, password FROM EmployeeInfo WHERE username = ?"; 
     Query query = session.createQuery(sql_query); 
     query.setString(0, username); 
     List<Employee> employees = (List<Employee>)query.list(); 

     return employees; 
} 

LoginController.java

@RequestMapping(value = "/edit", method=RequestMethod.GET) 
public ModelAndView EditMyInfo(ModelMap model, @ModelAttribute("editForm") Employee employee, HttpSession session) { 

List<Employee> user_info = emp_service.getUserinfo((String)session.getAttribute("session_username")); 
List<String> professionList = new ArrayList(); 
professionList.add("Developer"); 
professionList.add("Designer"); 
professionList.add("IT Manager"); 
model.put("professionList", professionList); 
employee.setUsername(user_info.get(0).getUsername().toString()); 
employee.setFirstname(user_info.get(0).getFirstname().toString()); 
employee.setLastname(user_info.get(0).getLastname().toString()); 
employee.setEmail(user_info.get(0).getEmail().toString()); 
employee.setMobileno(user_info.get(0).getMobileno().toString()); 
employee.setBirthdate(user_info.get(0).getBirthdate()); 
return new ModelAndView("edit",model); 
} 

edit.jsp文件

<%@page contentType="text/html" pageEncoding="UTF-8"%> 
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %> 
<%@taglib uri="http://www.springframework.org/tags/form" prefix="form" %> 
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> 
<html> 
<body> 
<c:if test="${session_username != null }">Hello ${session_username}!</c:if> 
    <font face="verdana" size="2"> 
     ${welcomeMessage} <BR><BR> 
     <form:form action="${pageContext.request.contextPath}/editemployee" method="POST" modelAttribute="editForm"> 

      <table> 
       <tr> 
        <td colspan="2" align="center">Spring MVC Form Demo - Edit</td> 
       </tr> 
       <tr> 
        <td>User Name</td> 
        <td><form:input path="username" /></td> 
       </tr> 
       <tr> 
        <td>First Name</td> 
        <td><form:input path="firstname" /></td> 
       </tr> 
       <tr> 
        <td>Last Name</td> 
        <td><form:input path="lastname" /></td> 
       </tr> 
       <tr> 
        <td>Mobile No.</td> 
        <td><form:input path="mobileno" /></td> 
       </tr> 
       <tr> 
        <td>Password</td> 
        <td><form:password path="password" /></td> 
       </tr> 
       <tr> 
        <td>Email</td> 
        <td><form:input path="email" /></td> 
       </tr> 
       <tr> 
        <td>BirthDate (mm/dd/yyyy)</td> 
        <td><form:input path="birthdate" /></td> 
       </tr> 
       <tr> 
        <td>Profession</td> 
        <td><form:select path="profession" items="${professionList}" /></td> 
       </tr> 
       <tr> 
        <td colspan="2" align="center"><input type="submit" value="Submit" /></td> 
       </tr>         
      </table>           
     </form:form> 
    </font> 
</body> 
</html> 

錯誤：

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to java4s.model.Employee 
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:979) 
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:858) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:621) 
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:843) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728) 

root cause 

java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to java4s.model.Employee 
    java4s.controller.LoginSuccessController.EditMyInfo(LoginSuccessController.java:106) 
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    java.lang.reflect.Method.invoke(Method.java:606) 
    org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221) 
    org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137) 
    org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110) 
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:776) 
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:705) 
    org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) 
    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:967) 
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:858) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:621) 
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:843) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728) 

我發現的錯誤是

employee.setUsername(user_info.get(0).getUsername().toString()); 
employee.setFirstname(user_info.get(0).getFirstname().toString()); 
employee.setLastname(user_info.get(0).getLastname().toString()); 
employee.setEmail(user_info.get(0).getEmail().toString()); 
employee.setMobileno(user_info.get(0).getMobileno().toString()); 
employee.setBirthdate(user_info.get(0).getBirthdate()); 

我該如何解決這個問題？

Answer 1

有在你的代碼

一些問題，你需要@Entity和@Table註釋添加到Employ 爲@KonstantinPavlov建議。

您需要userid上的@Id註釋。

此代碼是不正確

String sql_query = "SELECT username, firstname, lastname, 
    emailid, profession, mobileno, to_char(birthdate, 'MM/DD/YYYY') AS 
    birthdate, password FROM EmployeeInfo WHERE username = ?"; 

Query query = session.createQuery(sql_query); 
query.setString(0, username); 
List<Employee> employees = (List<Employee>)query.list(); 

你需要Employee但是你用FROM EmployeeInfo。 Hibernate無法將您的投影轉換爲Employee（它需要一個變換器或帶查詢中的構造函數的new運算符）。你的查詢看起來像SQL，但你需要HQL。

String hqlQuery = "FROM Employee WHERE username = :userName"; 

Query query = session.createQuery(hqlQuery); 
query.setParameter("userName", username); 
List<Employee> employees = (List<Employee>)query.list(); 

你並不需要建立SessionFactory爲每個請求！你需要使用Spring的LocalSessionFactoryBean來創建它。

您打開一個會話但不關閉它。

您開始一個事務但不提交或回滾它。