如果存在则在hibernate中搜索记录然后链接到表employee其他创建然后链接

Question

employee.java的代码

package Data;

import java.io.Serializable;
import java.util.*;

import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinTable;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
import javax.persistence.Transient;

@Entity
public class Employee implements Serializable {


private int empid;
private String empName;
private String empEmailAddress;
private boolean isActive;
    private String empAddress;
    private String empphone;
    @OneToMany
    private List<Department> deptobj;= new ArrayList<Department>();

    private  String emprole;
    private Integer salary;


    public void setdeptobj(List<Department> deptobj) {
    this.deptobj; = deptobj;
}
public List<Department> getdeptobj() {
    return deptobj;;
}

public void setempEmailAddress(String empEmailAddress) {
    this.empEmailAddress = empEmailAddress;
}
public String getempEmailAddress() {
    return empEmailAddress;
}
    public boolean getisActive() {
    return isActive;
}
public void setisActive(boolean isActive) {
    this.isActive = isActive;
}
    public String getempAddress() {
    return empAddress;
}
public void setempAddress(String empAddress) {
    this.empAddress = empAddress;
}
public String getempphone() {
    return empphone;
}
public void setempphone(String empphone) {
    this.empphone = empphone;
}


public String getemprole() {
    return emprole;
}
public void setemprole(String emprole) {
    this.emprole = emprole;
}

    public int getsalary() {
    return salary;
}
public void setsalary(int salary) {
    this.salary = salary;
}

@Id
public int getEmpid() {
    return empid;
}
public void setEmpid(int empid) {
    this.empid = empid;
}
public String getEmpName() {
    return empName;
}
public void setEmpName(String empName) {
    this.empName = empName;
}

}

Department.java的代码

package Data;

import java.util.ArrayList;
import java.util.List;
import javax.annotation.Generated;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;


@Entity
public class Department {
private String dept;

@ManyToOne
private Employee employee;
@Id
private int deptid;

public String getdept() {
    return dept;
}
public void setdept(String dept) {
    this.dept = dept;
}

    public int getdeptid() {
    return deptid;
}
public void setdeptid(int deptid) {
    this.deptid = deptid;
}

   private Employee getemployee(){
       return employee;
   }

   private void setemployee(Employee employee){
       this.employee = employee;
   }

}

中间层代码

package service;

import Data.*;
import static com.mchange.v2.log.MLog.config;
import java.io.Serializable;
import java.util.List;
import javax.imageio.spi.ServiceRegistry;
import javax.persistence.Query;
import org.hibernate.SQLQuery;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.cfg.Configuration;


public class ServiceLayer {
SessionFactory sessionFactory = new AnnotationConfiguration().configure("hibernate.cfg.xml").buildSessionFactory();

Session session = sessionFactory.openSession() ;


public void add(Employee emp){


    session.beginTransaction();
            System.out.println("hello");
            session.save(emp);
            System.out.println("hello");
            session.getTransaction().commit();

}

public void delete(int empid){


    session.beginTransaction();

            Employee emp = (Employee) session.get(Employee.class, empid);
            session.delete(emp);
            session.getTransaction().commit();

}

public void update(Employee emp){

    session.beginTransaction();
            session.update(emp);
            session.getTransaction().commit();
}

public void read(){

    session.beginTransaction();
            String hql = "select * from Employee;";
            session.createSQLQuery(hql);
            session.getTransaction().commit();

 }

 public Department check(String dept){
   session.beginTransaction();

    SQLQuery q = session.createSQLQuery("from Department d where d.dept=:deptname");
    q.setParameter("deptname", dept);
    Department d = (Department) q.uniqueResult();

    session.getTransaction().commit();
    return d;
}
 public Department getDept(Department list){

   session.beginTransaction();
  Department deptobj= (Department) session.get(Department.class, (Serializable) list.getdeptid());
   session.getTransaction().commit();
   return deptobj;
}

public void addDept(Department dep){
   session.beginTransaction();
   session.save(dep);

   session.getTransaction().commit();
}

}

主服务层代码

package mainService;

import Data.*;
import static java.sql.Types.NULL;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;
import service.ServiceLayer;


public class Logic {
private int empid;
private String empName;
ServiceLayer sl = new ServiceLayer();
private String empPassword;
private String empEmailAddress;
private boolean isPermanent;
private Calendar empJoinDate;



public void add(String empName,String empEmailAddress,String empAddress,String empphone,String dept,String emprole,Integer salary,boolean active){
    Employee emp = new Employee();
    emp.setEmpName(empName);
    emp.setempAddress(empAddress);
    emp.setempEmailAddress(empEmailAddress);
    emp.setempphone(empphone);

    emp.setemprole(emprole);
    emp.setsalary(salary);
    emp.setisActive(active);
    Department dep = null;

   Department list = sl.check(dept);
    if(list.getdeptid()==NULL){
      dep = addDept(dept);
    }
    else{
    dep = sl.getDept(list);
    }

    emp.getdeptobj().add((Department) dep);
    sl.add(emp);
}

private Department addDept(String dept) {
    Department dep = new Department();
    dep.setdept(dept);
    sl.addDept(dep);
    Department list = sl.check(dept);
    dep = (Department) sl.getDept(list);
    return dep;

}

}

服务层从swing中创建的表单中获取值，然后将数据传递给ServiceLayer.java文件，该文件创建会话并设置值以创建记录，然后保存该记录问题是我想检查是否部门已存在，然后链接与该搜索的链接将基于用户给出的部门名称，如果部门没有exixt然后首先创建新部门，然后链接到员工。

我无法解决问题所在，因为我之前没有使用过hibernate ...所以请帮助我。在运行文件时，我得到了

的错误

Exception in thread "AWT-EventQueue-0" org.hibernate.MappingException: 
     Could not determine type for: java.util.List, for columns:
     [org.hibernate.mapping.Column(deptobj)])

Answer 1

您可以始终如一地将JPA注释放在getter上，或者将它们放在字段上。将两者混合在一个类中会使Hibernate忽略所有与@Id注释放在同一位置的内容。

另外，你的映射很奇怪：一个部门有一个员工，也属于其他部门？这是一个单人公司做一切的映射吗？您可能希望在另一个方向上建立关联：一个部门有很多员工，每个员工都属于一个部门。