一、创建maven工程，引入依赖，设置配置文件

依赖和配置文件的设置可以参考，之前的博客《springdata__jpa》

二、创建实体类

1.customer类

package cn.dzl.jpa.entity;

import javax.persistence.*;

@Entity
@Table(name = "cust_customer")
public class Customer {
    //设置主键自增策略
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Id
    private long custId;
    private String custName;
    private String custSource;
    private String  custIndustry;
    private String custLevel;
    private String custAddress;
    private String custPhone;

    @PrimaryKeyJoinColumn//主键关联
    @OneToOne(cascade = CascadeType.ALL)//设置联级关联，效果是，两个有关联的表，可以单独地改变其中一个表
    private CustomerExt ext; //该字段表明关联的是哪个表对象

    public CustomerExt getExt() {
        return ext;
    }

    public void setExt(CustomerExt ext) {
        this.ext = ext;
    }

    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 "Customer{" +
                "custId=" + custId +
                ", custName='" + custName + '\'' +
                ", custSource='" + custSource + '\'' +
                ", custIndustry='" + custIndustry + '\'' +
                ", custLevel='" + custLevel + '\'' +
                ", custAddress='" + custAddress + '\'' +
                ", custPhone='" + custPhone + '\'' +
                '}';
    }
}

2.CustomerExt类

package cn.dzl.jpa.entity;

import javax.persistence.*;

@Entity
@Table(name = "customer_ext")
public class CustomerExt {
    @Id//该注解在哪一个字段上，哪个字段就是主键
    @GeneratedValue(strategy = GenerationType.IDENTITY)//设置主键为自增状态
    private long extId;
    private String memo;
    private String info;
    @PrimaryKeyJoinColumn//该注解表明两个表之间是主键关联
    @OneToOne//两个表之间的关系是一对一
    private Customer customer;//该字段表明，关联的是哪个表对象

    public Customer getCustomer() {
        return customer;
    }

    public void setCustomer(Customer customer) {
        this.customer = customer;
    }

    public long getExtId() {
        return extId;
    }

    public void setExtId(long extId) {
        this.extId = extId;
    }

    public String getMemo() {
        return memo;
    }

    public void setMemo(String memo) {
        this.memo = memo;
    }

    public String getInfo() {
        return info;
    }

    public void setInfo(String info) {
        this.info = info;
    }

    @Override
    public String toString() {
        return "CustomerExt{" +
                "extId=" + extId +
                ", memo='" + memo + '\'' +
                ", info='" + info + '\'' +
                '}';
    }
}

三、创建dao接口(一定要继承JpaRepository<实体类型，主键类型>)

1.CustomerDao

package cn.dzl.jpa.dao;

import cn.dzl.jpa.entity.Customer;
import org.springframework.data.jpa.repository.JpaRepository;

public interface CustomerDao extends JpaRepository<Customer,Long> {
}

2.CustomerExtDao

package cn.dzl.jpa.dao;

import cn.dzl.jpa.entity.CustomerExt;
import org.springframework.data.jpa.repository.JpaRepository;

public interface CustomerExtDao extends JpaRepository<CustomerExt,Long> {
}

四、测试类OneToOne

package cn.dzl;

import cn.dzl.jpa.dao.CustomerDao;
import cn.dzl.jpa.dao.CustomerExtDao;
import cn.dzl.jpa.entity.Customer;
import cn.dzl.jpa.entity.CustomerExt;
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 OneToOne {
    @Autowired
    CustomerDao customerDao;
    @Autowired
    CustomerExtDao customerExtDao;
    @Test
    //更改数据库，需要用到事物
    @Transactional
    //提交
    @Commit
    public void addCustomer(){
        //创建customer对象
        Customer customer = new Customer();
        customer.setCustName("丁老大");
        customer.setCustAddress("北京");
        //创建customerExt对象
        CustomerExt customerExt = new CustomerExt();
        customerExt.setInfo("今天心情不错");
        customerExt.setMemo("打球去");
        //设置对象关联关系
        customer.setExt(customerExt);
        customerExt.setCustomer(customer);
        //调用dao层方法保存到数据库中
        customerDao.save(customer);
//        customerExtDao.save(customerExt);
    }
}