一对一关系数据库表 java类描述

一对一关系中 从表的主键是 主表的外键

sql语句

create table person(
    id int primary key,
    name varchar(100)
);
create table idcard(
    id int primary key,
    num varchar(20),
    constraint person_id_fk foreign key(id) references person(id)
);

domain

Person.java

package cn.itcast.domain;

import java.io.Serializable;
/*
create table person(
    id int primary key,
    name varchar(100)
);
create table idcard(
    id int primary key,
    num varchar(20),
    constraint person_id_fk foreign key(id) references person(id)
);
 */
public class Person implements Serializable {
    private Integer id;
    private String name;
    private IdCard idcard;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public IdCard getIdcard() {
        return idcard;
    }
    public void setIdcard(IdCard idcard) {
        this.idcard = idcard;
    }
    
}

IdCard.java

package cn.itcast.domain;

import java.io.Serializable;

public class IdCard implements Serializable {
    private Integer id;
    private String num;
    private Person person;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getNum() {
        return num;
    }
    public void setNum(String num) {
        this.num = num;
    }
    public Person getPerson() {
        return person;
    }
    public void setPerson(Person person) {
        this.person = person;
    }
    
}

daoImpl.java

package cn.itcast.dao.impl;

import java.sql.SQLException;

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;

import cn.itcast.domain.IdCard;
import cn.itcast.domain.Person;
import cn.itcast.util.DBCPUtil;

public class PersonDaoImpl {
    private QueryRunner qr = new QueryRunner(DBCPUtil.getDataSource());
    public void addPerson(Person p) throws SQLException{
        //保存人的基本信息
        qr.update("insert into person (id,name) values(?,?)", p.getId(),p.getName());
        //如果有身份证，保存身份证的基本信息
        IdCard card = p.getIdcard();
        if(card!=null){
            qr.update("insert into idcard (id,num) values(?,?)", p.getId(),card.getNum());
        }
    }
    //要不要查IdCard的内容。都要求查，因为Idcard是少的一方的
    public Person findPerson(Integer id) throws SQLException{
        Person p = qr.query("select * from person where id=?", new BeanHandler<Person>(Person.class), id);
        if(p!=null){
            IdCard idcard = qr.query("select * from idcard where id=?", new BeanHandler<IdCard>(IdCard.class), id);
            p.setIdcard(idcard);
        }
        return p;
    }
}

test测试

package cn.itcast.test;

import static org.junit.Assert.fail;

import java.sql.SQLException;

import org.junit.Test;

import cn.itcast.dao.impl.PersonDaoImpl;
import cn.itcast.domain.IdCard;
import cn.itcast.domain.Person;

public class PersonDaoImplTest {
    private PersonDaoImpl dao = new PersonDaoImpl();
    @Test
    public void testAddPerson() throws SQLException {
        Person p = new Person();
        p.setId(1);
        p.setName("zql");
        
        IdCard idcard = new IdCard();
        idcard.setNum("110");
        
        p.setIdcard(idcard);
        dao.addPerson(p);
    }

    @Test
    public void testFindPerson() throws SQLException {
        Person p = dao.findPerson(1);
        System.out.println(p.getName());
        IdCard idcard = p.getIdcard();
        System.out.println(idcard.getNum());
    }

}