Question

下面是我的代码我想在我的公司类和Person类中实现OnetoMany Hibernate Mapping 代码对我来说似乎正确但是打印数据时输出有错误如果有人可以帮我解决这个问题，那就太好了。

我希望从公司类到多人的一对多映射，一次打印所有映射数据

package Rajat.Practice1;

import java.util.ArrayList;
import java.util.List;

import javax.persistence.Column;
import javax.persistence.ElementCollection;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.OneToMany;
import javax.persistence.Table;

@Entity
public class Company {

    private int c_id;
    private String C_name;


    public List<Person> person = new ArrayList<Person>();

    @Id
    @GeneratedValue
    @Column(name="c_id")
    public int getC_id() {
        return c_id;
    }
    public void setC_id(int c_id) {
        this.c_id = c_id;
    }
    @Column(name="name")
    public String getC_name() {
        return C_name;
    }
    public void setC_name(String c_name) {
        C_name = c_name;
    }
    @Override
    public String toString() {
        return "Company [c_id=" + c_id + ", C_name=" + C_name + ", person=" + person + "]";
    }
     public List<Person> getPerson() {
            return person;
        }
        @OneToMany(mappedBy="company", fetch=FetchType.EAGER)

        public void setPerson(List<Person> person) {
            this.person = person;
        }
    }

公司类

package Rajat.Practice1;

import javax.persistence.Column;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.OneToOne;
import javax.persistence.Table;

import org.hibernate.annotations.CascadeType;
import org.hibernate.annotations.CollectionId;
import javax.persistence.Entity;
import org.hibernate.annotations.Fetch;

@Entity
public class Person {


    private int Pid;

    private String name;

    public Company company;

    private PersonDetail p_detail;

    //@OneToOne ( cascade=javax.persistence.CascadeType.ALL, fetch=FetchType.EAGER  )
    //@JoinColumn(name="pdetail_pk")
    public PersonDetail getP_detail() {
        return p_detail;
    }
    public void setP_detail(PersonDetail p_detail) {
        this.p_detail = p_detail;
    }

    @Id
    @GeneratedValue
    @Column(name="Pid_pk")
    public int getPid() {
        return Pid;
    }
    public void setPid(int pid) {
        Pid = pid;
    }

    @Column(name="name")
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }


   // @ManyToOne(fetch=FetchType.EAGER)
   // @JoinColumn(name="c_id")
    public Company getCompany() {
        return company;
    }

    public void setCompany(Company company) {
        this.company = company;
    }
    @Override
    public String toString() {
        return "Person [Pid=" + Pid + ", name=" + name + ", company=" + company + ", p_detail=" + p_detail + "]";
    }

}

人类

package Rajat.Practice1;

import java.util.ArrayList;
import java.util.List;

import javax.imageio.spi.ServiceRegistry;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistryBuilder;
import org.hibernate.tool.hbm2ddl.SchemaExport;

public class Main {


    public static void main(String[] args) {

         Configuration cfg=new Configuration();  
            cfg.configure("hibernate.cfg.xml");  

            SessionFactory sf=cfg.buildSessionFactory();  
            Session session=sf.openSession();  
            Transaction tx=session.beginTransaction();  
            List <Person> lp=new ArrayList<Person>();
            PersonDetail pd=new  PersonDetail();
            pd.setCity("jaipur");
            pd.setState("jaipur");

            Person p=new Person();
            p.setName("Rajat");

            Person p1=new Person();
            p1.setName("Dynamo");


            Company c=new Company();
            c.setC_name("Protechgenie");


            p.setCompany(c);
            p1.setCompany(c);

        c.getPerson().add(p);
        c.getPerson().add(p1);


        lp.add(p);
        lp.add(p1);

        p.setP_detail(pd);

        session.save(c);
        session.save(p);
        session.save(p1);


        session.getTransaction().commit();
        Company com=(Company)session.get(Company.class, 1);
        Person per=(Person) session.get(Person.class, 1);
        System.out.println(com);

    }

}

主类

{{1}}

Answer 1

在Company类中，取消注释映射配置
在Person类中，注释（@OneToMany(mappedBy="company", fetch=FetchType.EAGER)）应该在getter方法上。

这是我的代码（注意我删除了一些未使用的属性）

@Entity
public class Company {

private int c_id;
private String C_name;

public List<Person2> person = new ArrayList<Person2>();

@Id
@GeneratedValue
@Column(name="c_id")
public int getC_id() {
    return c_id;
}
public void setC_id(int c_id) {
    this.c_id = c_id;
}
@Column(name="name")
public String getC_name() {
    return C_name;
}
public void setC_name(String c_name) {
    C_name = c_name;
}
@Override
public String toString() {
    return "Company [c_id=" + c_id + ", C_name=" + C_name + ", person=" + person + "]";
}

@OneToMany(mappedBy="company", fetch=FetchType.EAGER)
public List<Person2> getPerson() {
    return person;
}


public void setPerson(List<Person2> person) {
    this.person = person;
}
}

@Entity
public class Person2 {

private int Pid;

private String name;

public Company company;

@Id
@GeneratedValue
@Column(name="Pid_pk")
public int getPid() {
    return Pid;
}
public void setPid(int pid) {
    Pid = pid;
}

@Column(name="name")
public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}


@ManyToOne(fetch=FetchType.EAGER)
@JoinColumn(name="c_id")
public Company getCompany() {
    return company;
}

public void setCompany(Company company) {
    this.company = company;
}
@Override
public String toString() {
    return "Person [Pid=" + Pid + ", name=" + name + ", company=" + company + "]";
}

休眠一对多注释（映射）错误

1 个答案: