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());
     }

 }