springdata_多表关系中的一对多__小案例

一、创建maven工程，引入依赖和创建配置文件

依赖和配置文件参考，之前的博客《springdata——jpa》

二、创建实体类

1.customer1

package cn.dzl.jpa.entity;

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

@Entity
@Table(name="cst_customer1")
public class Customer1 {
    //配置主键生成的策略
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    //配置主键使用的字段
    @Id
    private long custId;
    private String custName;
    private String custSource;
    private String  custIndustry;
    private String custLevel;
    private String custAddress;
    private String custPhone;
    //all代表所有情况下都关联操作， lazy表示懒加载，该属性不会马上从数据库加载
    @OneToMany(cascade = CascadeType.ALL,fetch = FetchType.LAZY)
    private Set<LinkMan>linkMen=new HashSet<>();//因为，联系人有多个，所有用集合存

    public Set<LinkMan> getLinkMen() {
        return linkMen;
    }

    public void setLinkMen(Set<LinkMan> linkMen) {
        this.linkMen = linkMen;
    }

    public long getCustId() {
        return custId;
    }

    public void setCustId(long custId) {
        this.custId = custId;
    }

    public String getCustName() {
        return custName;
    }

    public void setCustName(String custName) {
        this.custName = custName;
    }

    public String getCustSource() {
        return custSource;
    }

    public void setCustSource(String custSource) {
        this.custSource = custSource;
    }

    public String getCustIndustry() {
        return custIndustry;
    }

    public void setCustIndustry(String custIndustry) {
        this.custIndustry = custIndustry;
    }

    public String getCustLevel() {
        return custLevel;
    }

    public void setCustLevel(String custLevel) {
        this.custLevel = custLevel;
    }

    public String getCustAddress() {
        return custAddress;
    }

    public void setCustAddress(String custAddress) {
        this.custAddress = custAddress;
    }

    public String getCustPhone() {
        return custPhone;
    }

    public void setCustPhone(String custPhone) {
        this.custPhone = custPhone;
    }

    @Override
    public String toString() {
        return "Customer1{" +
                "custId=" + custId +
                ", custName='" + custName + '\'' +
                ", custSource='" + custSource + '\'' +
                ", custIndustry='" + custIndustry + '\'' +
                ", custLevel='" + custLevel + '\'' +
                ", custAddress='" + custAddress + '\'' +
                ", custPhone='" + custPhone + '\'' +
                '}';
    }
}

　　2.LinkMan

package cn.dzl.jpa.entity;

import javax.persistence.*;

@Entity
@Table(name="cust_linkman")
public class LinkMan {
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Id
    private long id;
    private String name;
    private String gender;
    private String phone;
    private String position;
    @ManyToOne(fetch = FetchType.LAZY)//懒加载，该属性，不会马上在数据库加载
    @JoinColumn(name = "custName",referencedColumnName = "custName")//要关联的列，在实体类中的名字和在表中的名字
    private Customer1 customer1;//要关联的是哪一个表

    public long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    public String getPosition() {
        return position;
    }

    public void setPosition(String position) {
        this.position = position;
    }

    public Customer1 getCustomer1() {
        return customer1;
    }

    public void setCustomer1(Customer1 customer1) {
        this.customer1 = customer1;
    }

    @Override
    public String toString() {
        return "LinkMan{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", gender='" + gender + '\'' +
                ", phone='" + phone + '\'' +
                ", position='" + position + '\'' +
                ", customer1=" + customer1 +
                '}';
    }
}

　　三、dao接口

1.customer1Dao

package cn.dzl.jpa.dao;import cn.dzl.jpa.entity.Customer1;import org.springframework.data.jpa.repository.JpaRepository;public interface Customer1Dao extends JpaRepository<Customer1,Long> {}2.LinkManDao

package cn.dzl.jpa.dao;import cn.dzl.jpa.entity.LinkMan;import org.springframework.data.jpa.repository.JpaRepository;public interface LinkManDao extends JpaRepository<LinkMan,Long> {}四、测试类

package cn.dzl;

import cn.dzl.jpa.dao.Customer1Dao;
import cn.dzl.jpa.dao.LinkManDao;
import cn.dzl.jpa.entity.Customer1;
import cn.dzl.jpa.entity.LinkMan;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.annotation.Commit;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.transaction.annotation.Transactional;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class OneToMany {
    @Autowired
    Customer1Dao customer1Dao;
    @Autowired
    LinkManDao linkManDao;
    @Test
    @Transactional
    @Commit
    public void addCustomer(){
        //创建customer1对象
        Customer1 customer1 = new Customer1();
        customer1.setCustName("xiaoming");
        customer1.setCustAddress("郑州");
        customer1.setCustPhone("123");
        customer1.setCustLevel("老师");
        //创建第一个LinkMan对象
        LinkMan linkMan1 = new LinkMan();
        linkMan1.setName("小红");
        linkMan1.setPhone("000");
        //创建第二个LinkMan对象
        LinkMan linkMan2 = new LinkMan();
        linkMan2.setName("小东");
        linkMan2.setPhone("111");
        //设置对象之间的关联关系
        customer1.getLinkMen().add(linkMan1);
        customer1.getLinkMen().add(linkMan2);
        linkMan1.setCustomer1(customer1);
        linkMan2.setCustomer1(customer1);
        //使用dao层把数据写入数据库
        customer1Dao.save(customer1);
//        linkManDao.save(linkMan1);
//        linkManDao.save(linkMan2);


    }
}

　　

来源：https://www.cnblogs.com/Hubert-dzl/p/11665412.html