注解-单向一对多演示

首先定义2个实体类:Cate.java和Sub.java

单向一对多：一方有集合属性，包含多个多方，而多方没有一方的引用

package com.yztc.app.entity;

import javax.persistence.*;
import java.util.Set;

@Entity
@Table(name = "TB_CATE")
public class Cate {
    @Id
    @GeneratedValue//用于定义主键生成策略
    @Column(name = "CID",length = 10)
    private Long cid;
    @Column(name = "NAME",length = 64)
    private String name;
    @OneToMany(cascade = CascadeType.ALL)
    @JoinColumn(name = "CID")
    private Set<Sub> subs;

    public Set<Sub> getSubs() {
        return subs;
    }

    public void setSubs(Set<Sub> subs) {
        this.subs = subs;
    }

    public Long getCid() {
        return cid;
    }

    public void setCid(Long cid) {
        this.cid = cid;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Cate() {
    }

    public Cate(String name) {
        this.name = name;
    }
}

package com.yztc.app.entity;

import javax.persistence.*;

@Entity
@Table(name = "TB_SUB")
public class Sub {
    @Id
    @GeneratedValue//用于定义主键生成策略
    @Column(name = "SID",length = 10)
    private Long sid;
    @Column(name = "NAME",length = 64)
    private String name;


    public Sub() {
    }

    public Long getSid() {

        return sid;
    }

    public void setSid(Long sid) {
        this.sid = sid;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Sub(String name) {
        this.name = name;
    }
}

二.单元测试:

package com.yztc.test;


import com.yztc.app.entity.Cate;
import com.yztc.app.entity.Sub;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.util.HashSet;
import java.util.Set;

public class TestOneToMany {

    private SessionFactory sf;
    private Session session;

    @Before
    public void init(){
        sf = new Configuration().configure().buildSessionFactory();
        session = sf.openSession();

    }
    //测试一对多单向
    @Test
    public void testSave(){
        Transaction transaction = session.beginTransaction();
        Cate cate = new Cate("手机");
        Set<Sub> sets = new HashSet<>();
        for (int i = 0; i < 10; i++) {
            Sub sub = new Sub("魅族" + i);
            sets.add(sub);
            session.save(sub);
        }
       cate.setSubs(sets);
        session.save(cate);
        transaction.commit();


    }
    @After
    public void destory(){
        session.close();
    }
}