春/ Hibernate的CRUD不工作（MySQL的）

我試圖做一個簡單的Spring /休眠/ MySQL的CRUD，但它不工作：/我：春/ Hibernate的CRUD不工作（MySQL的）

HTTP狀態500 - 內部服務器錯誤

類型例外報告

消息：請求處理失敗;嵌套的異常是 java.lang.IllegalArgumentException異常： org.hibernate.hql.internal.ast.QuerySyntaxException：僱員不映射[取自last_name的員工爲了]

描述：服務器遇到意外的條件，即阻止它履行請求。

這裏是我的代碼：

Employee.java

package com.employeemanager.entity; 

import java.util.Set; 

import javax.persistence.Column; 
import javax.persistence.Entity; 
import javax.persistence.GeneratedValue; 
import javax.persistence.GenerationType; 
import javax.persistence.Id; 
import javax.persistence.Table; 

@Entity 
@Table(name="employees") 
public class Employee { 

@Id 
@GeneratedValue(strategy=GenerationType.IDENTITY) 
@Column(name="id") 
private int id; 

@Column(name="first_name") 
private String firstName; 

@Column(name="last_name") 
private String lastName; 

@Column(name="email") 
private String email; 

@Column(name="username") 
private String username; 

@Column(name="password") 
private String password; 


public Employee(){ 

} 
public Employee(String firstName){ 

} 
public Employee(String firstName,Set<Project> projects){ 
    this.firstName=firstName; 
    this.projects=projects; 
} 

public int getId() { 
    return id; 
} 

public void setId(int id) { 
    this.id = id; 
} 

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 getEmail() { 
    return email; 
} 

public void setEmail(String email) { 
    this.email = email; 
} 

public String getUsername() { 
    return username; 
} 

public void setUsername(String username) { 
    this.username = username; 
} 

public String getPassword() { 
    return password; 
} 

public void setPassword(String password) { 
    this.password = password; 
} 


}

EmployeeDAO.java

package com.employeemanager.dao; 

import java.util.List; 

import com.employeemanager.entity.Employee; 

public interface EmployeeDAO { 

public List<Employee> getEmployees(); 

public void saveEmployee(Employee theEmployee); 

public Employee getEmployee(int theId); 

public void deleteEmployee(int theId); 


}

EmployeeDAOImpl.java

package com.employeemanager.dao; 

import java.util.List; 

import org.hibernate.Session; 
import org.hibernate.SessionFactory; 
import org.springframework.beans.factory.annotation.Autowired; 
import org.springframework.stereotype.Repository; 


import com.employeemanager.entity.Employee; 

@Repository 
public class EmployeeDAOImpl implements EmployeeDAO { 


@Autowired 
private SessionFactory sessionFactory; 


@Override 
public List<Employee> getEmployees() { 

    Session currentSession=sessionFactory.getCurrentSession(); 
    List<Employee> employeeList= 
      currentSession.createQuery("from employees order by 
last_name").getResultList(); 
    return employeeList; 
} 

@Override 
public void saveEmployee(Employee theEmployee) { 

    Session currentSession=sessionFactory.getCurrentSession(); 
    currentSession.saveOrUpdate(theEmployee); 

} 


@Override 
public Employee getEmployee(int theId) { 

Session currentSession=sessionFactory.getCurrentSession(); 

Employee theEmployee=currentSession.get(Employee.class, theId); 

return theEmployee; 

} 


@Override 
public void deleteEmployee(int theId) { 

    Session currentSession=sessionFactory.getCurrentSession(); 

    Employee employee=((Employee) 
currentSession.load(Employee.class,theId)); 
    if(null!=employee){ 
     this.sessionFactory.getCurrentSession().delete(employee); 
    } 
} 

}

EmployeeService.java

package com.employeemanager.service; 

import java.util.List; 

import com.employeemanager.entity.Employee; 

public interface EmployeeService { 

public List<Employee> getEmployees(); 

public void saveEmployee(Employee theEmployee); 

public Employee getEmployee(int theId); 

public void deleteEmployee(int theId); 


}

EmployeeServiceImpl.java

package com.employeemanager.service; 

import java.util.List; 

import org.springframework.beans.factory.annotation.Autowired; 
import org.springframework.stereotype.Service; 
import org.springframework.transaction.annotation.Transactional; 

import com.employeemanager.entity.Employee; 
import com.employeemanager.dao.EmployeeDAO; 

@Service 
public class EmployeeServiceImpl implements EmployeeService { 

@Autowired 
private EmployeeDAO employeeDAO; 

@Override 
@Transactional 
public List<Employee> getEmployees() { 

    return employeeDAO.getEmployees(); 
} 

@Override 
@Transactional 
public void saveEmployee(Employee theEmployee) { 

    employeeDAO.saveEmployee(theEmployee); 
} 

@Override 
@Transactional 
public Employee getEmployee(int theId) { 

    return employeeDAO.getEmployee(theId); 
} 

@Override 
@Transactional 
public void deleteEmployee(int theId) { 

    employeeDAO.deleteEmployee(theId); 

} 

}

EmployeeController.java

package com.employeemanager.controller; 

import java.util.List; 

import org.springframework.beans.factory.annotation.Autowired; 
import org.springframework.stereotype.Controller; 
import org.springframework.ui.Model; 
import org.springframework.web.bind.annotation.GetMapping; 
import org.springframework.web.bind.annotation.ModelAttribute; 
import org.springframework.web.bind.annotation.PostMapping; 
import org.springframework.web.bind.annotation.RequestMapping; 
import org.springframework.web.bind.annotation.RequestParam; 

import com.employeemanager.entity.Employee; 
import com.employeemanager.entity.Project; 
import com.employeemanager.service.EmployeeService; 
import com.employeemanager.service.ProjectService; 

@Controller 
@RequestMapping("/employee") 
public class EmployeeController { 

@Autowired 
private EmployeeService employeeService; 

@Autowired 
private ProjectService projectService; 

@GetMapping("/list") 
public String listEmployees(Model theModel){ 


    List<Employee> theEmployees=employeeService.getEmployees(); 

    theModel.addAttribute("employees",theEmployees); 

    return"employees-list"; 
} 

@GetMapping("/addEmployeeForm") 
public String addEmployeeForm(Model theModel){ 

    Employee theEmployee=new Employee(); 
    List<Project> theProjects=projectService.getProjects(); 
    theModel.addAttribute("projects",theProjects); 

    theModel.addAttribute("employee",theEmployee); 

    return"employee-form"; 
} 

@PostMapping("/saveEmployee") 
public String saveEmployee(@ModelAttribute("employee") Employee theEmployee) 
{ 

    employeeService.saveEmployee(theEmployee); 

    return "redirect:/employee/list"; 
} 

@GetMapping("/updateEmployeeForm") 
public String updateEmployeeForm(@RequestParam("employeeId") int theId, 
           Model theModel){ 

    Employee theEmployee=employeeService.getEmployee(theId); 
    theModel.addAttribute("employee",theEmployee); 

    return"employee-form"; 
} 

@GetMapping("/deleteEmployee") 
public String deleteEmployee(@RequestParam("employeeId") int theId){ 
    employeeService.deleteEmployee(theId); 
    return"redirect:/employee/list"; 
} 

}

你有任何想法如何解決這個問題呢？感謝您對所有您的幫助:)

來源

2017-06-01 Revi

你表示在application.properties正確的數據庫連接文件？ –

我認爲問題在於你試圖使用* table *名稱'employees'而不是實體名稱'Employee'。另請注意，Spring Data JPA可以免費爲您自動生成整個DAO代碼。 – chrylis

我認爲EmployeeDAOImpl.java中有錯誤。將「employees」更改爲「Employee」和「last_name」更改爲「lastName」（名稱應與映射類中的相同（Employee。JAVA））

只要改變：

@Override 
public List<Employee> getEmployees() { 

Session currentSession=sessionFactory.getCurrentSession(); 
List<Employee> employeeList= 
     currentSession.createQuery("from employees order by 
last_name").getResultList(); 
return employeeList; 
}

到：

@Override 
public List<Employee> getEmployees() { 

Session currentSession=sessionFactory.getCurrentSession(); 
List<Employee> employeeList= 
     currentSession.createQuery("from Employee order by 
lastName").getResultList(); 
return employeeList; 
}

，並告訴我們，如果它的工作:)

來源

2017-06-01 15:24:22 Revi

謝謝，它工作完美:) – Revi

我很高興聽到:) – Revi

如果使用HQL，那麼Java實體名稱應使用，而不是真正的表名：

@Repository 
public class EmployeeDAOImpl implements EmployeeDAO { 

    @Override 
    public List<Employee> getEmployees() { 
     Session currentSession = sessionFactory.getCurrentSession(); 
     return currentSession.createQuery("from Employee order by last_name").getResultList(); 
    } 
}

來源

2017-06-01 15:15:33

非常感謝你，工作給我:) – Revi

更改您的HQL從這個：

from employees order by last_name

要這樣：

from Employee e order by e.lastName

在HQL你應該使用namings與您的mappe d類。

來源

2017-06-01 15:19:29 eg04lt3r

感謝您的快速幫助，它的工作現在:) – Revi

@Hjalmar，你的歡迎=）你可以標記答案如果它幫助你接受。 – eg04lt3r

春/ Hibernate的CRUD不工作（MySQL的）

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