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Java基础-SSM之mybatis一对一外键关联

　　　　　　　　　　　　　　Java基础-SSM之mybatis一对一外键关联

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　作者：尹正杰

一.准备测试环境（创建数据库表）

1>.创建husbandsfk和wifesfk表

1 use yinzhengjie;
2 
3 create table husbandsfk(id int primary key auto_increment , hname varchar(20)) ;
4         
5 create table wifesfk(id int primary key  auto_increment , wname varchar(20) , hid int , CONSTRAINT fk_hid FOREIGN KEY (hid) references husbandsfk(id)) ;
6         
7 alter table wifesfk add constraint unq_hid unique (hid) ;

2>.添加Maven依赖

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <project xmlns="http://maven.apache.org/POM/4.0.0"
 3          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 5     <modelVersion>4.0.0</modelVersion>
 6     <groupId>cn.org.yinzhengjie</groupId>
 7     <artifactId>Mybatis</artifactId>
 8     <version>1.0-SNAPSHOT</version>
 9     <dependencies>
10         <dependency>
11             <groupId>junit</groupId>
12             <artifactId>junit</artifactId>
13             <version>4.11</version>
14         </dependency>
15         <dependency>
16             <groupId>mysql</groupId>
17             <artifactId>mysql-connector-java</artifactId>
18             <version>5.1.17</version>
19         </dependency>
20         <dependency>
21             <groupId>org.mybatis</groupId>
22             <artifactId>mybatis</artifactId>
23             <version>3.2.1</version>
24         </dependency>
25     </dependencies>
26 </project>

3>.目录结构如下：

二.编写自定义类

 1 /*
 2 @author :yinzhengjie
 3 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
 4 EMAIL:y1053419035@qq.com
 5 */
 6 package cn.org.yinzhengjie.mybatis.domain.one2one.fk;
 7 
 8 public class Husband {
 9     private Integer id ;
10     private String hname ;
11     private Wife wife;
12 
13     public Integer getId() {
14         return id;
15     }
16 
17     public void setId(Integer id) {
18         this.id = id;
19     }
20 
21     public String getHname() {
22         return hname;
23     }
24 
25     public void setHname(String hname) {
26         this.hname = hname;
27     }
28 
29     public Wife getWife() {
30         return wife;
31     }
32 
33     public void setWife(Wife wife) {
34         this.wife = wife;
35     }
36 }

Husband.java 文件内容

 1 /*
 2 @author :yinzhengjie
 3 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
 4 EMAIL:y1053419035@qq.com
 5 */
 6 package cn.org.yinzhengjie.mybatis.domain.one2one.fk;
 7 
 8 public class Wife {
 9     private Integer id ;
10     private String wname ;
11     private Husband husband ;
12 
13     public Integer getId() {
14         return id;
15     }
16 
17     public void setId(Integer id) {
18         this.id = id;
19     }
20 
21     public String getWname() {
22         return wname;
23     }
24 
25     public void setWname(String wname) {
26         this.wname = wname;
27     }
28 
29     public Husband getHusband() {
30         return husband;
31     }
32 
33     public void setHusband(Husband husband) {
34         this.husband = husband;
35     }
36 }

Wife.java 文件内容

三.编写配置文件

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 
 3 <!DOCTYPE configuration
 4         PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
 5         "http://mybatis.org/dtd/mybatis-3-config.dtd">
 6 <configuration>
 7     <properties>
 8         <property name="driver" value="com.mysql.jdbc.Driver"/>
 9         <!--注意 : “?characterEncoding=utf-8&amp;autoReconnect=true&amp;failOverReadOnly=false&amp;allowMultiQueries=true” 表示开启批处理模式-->
10         <property name="url" value="jdbc:mysql://localhost:5200/yinzhengjie?characterEncoding=utf-8&amp;autoReconnect=true&amp;failOverReadOnly=false&amp;allowMultiQueries=true"/>
11         <property name="username" value="root"/>
12         <property name="password" value="yinzhengjie"/>
13     </properties>
14 
15     <!-- 我们使用typeAliases标签给我们自定义类起个别名。-->
16     <typeAliases>
17         <typeAlias type="cn.org.yinzhengjie.mybatis.domain.one2one.fk.Husband"     alias="_HusbandFK" />
18         <typeAlias type="cn.org.yinzhengjie.mybatis.domain.one2one.fk.Wife"        alias="_WifeFK" />
19     </typeAliases>
20 
21     <environments default="development">
22         <environment id="development">
23             <transactionManager type="JDBC"/>
24             <dataSource type="POOLED">
25                 <property name="driver" value="${driver}"/>
26                 <property name="url" value="${url}"/>
27                 <property name="username" value="${username}"/>
28                 <property name="password" value="${password}"/>
29             </dataSource>
30         </environment>
31     </environments>
32     <mappers>
33         <!-- 我们使用mapper标签指定映射文件，使用resource指定具体的路径，如果没有写绝对路径，默认的根路径就在resources目录中-->
34         <mapper resource="HusbandFKMapper.xml"/>
35         <mapper resource="WifeFKMapper.xml"/>
36     </mappers>
37 </configuration>

mybatis-config.xml 文件内容

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
 3         "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 4 <!-- 定义名字空间 -->
 5 <mapper namespace="husbandsfk">
 6     <insert id="insert" useGeneratedKeys="true" keyProperty="id">
 7         insert into husbandsfk(hname) values(#{hname}) ;
 8     </insert>
 9 
10     <select id="selectOne" resultMap="rm_Husband">
11         select
12           h.id hid,
13           h.hname hhname ,
14           w.id wid ,
15           w.wname wwname ,
16           w.hid whid
17         from
18           husbandsfk h left outer join wifesfk w on w.hid = h.id
19         where
20           h.id = #{id}
21     </select>
22     
23     <resultMap id="rm_Husband" type="_HusbandFK">
24         <id column="hid" property="id"/>
25         <result column="hhname" property="hname" />
26         <association property="wife" javaType="_WifeFK" column="whid">
27             <id column="wid" property="id"/>
28             <result column="wwname" property="wname"/>
29             <association property="husband" javaType="_HusbandFk" column="whid">
30                 <id column="hid" property="id"/>
31                 <result column="hhname" property="hname"/>
32             </association>
33         </association>
34     </resultMap>
35 </mapper>

HusbandFKMapper.xml 文件内容

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
 3         "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 4 <!-- 定义名字空间 -->
 5 <mapper namespace="wifesfk">
 6     <insert id="insert" useGeneratedKeys="true" keyProperty="id">
 7         insert into wifesfk(wname , hid) values(#{wname} , #{husband.id}) ;
 8     </insert>
 9     
10 </mapper>

WifeFKMapper.xml 文件内容

四.编写测试代码

 1 /*
 2 @author :yinzhengjie
 3 Blog:http://www.cnblogs.com/yinzhengjie/tag/Java%E5%9F%BA%E7%A1%80/
 4 EMAIL:y1053419035@qq.com
 5 */
 6 package cn.org.yinzhengjie.mybatis.test;
 7 
 8 import cn.org.yinzhengjie.mybatis.domain.one2one.fk.Husband;
 9 import cn.org.yinzhengjie.mybatis.domain.one2one.fk.Wife;
10 import org.apache.ibatis.io.Resources;
11 import org.apache.ibatis.session.SqlSession;
12 import org.apache.ibatis.session.SqlSessionFactory;
13 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
14 import org.junit.Test;
15 
16 import java.io.InputStream;
17 
18 /**
19  * 测试一对一
20  */
21 public class TestOne2OneFK {
22     /**
23      * 测试插入
24      */
25     @Test
26     public void testInsert() throws Exception {
27         InputStream in = Resources.getResourceAsStream("mybatis-config.xml");
28         SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(in);
29         SqlSession sess = sf.openSession();
30         Husband h1 = new Husband();
31         h1.setHname("liyapeng");
32         Wife w1 = new Wife();
33         w1.setWname("wangfei");
34         h1.setWife(w1);
35         w1.setHusband(h1);
36 
37         sess.insert("husbandsfk.insert" , h1) ;
38         sess.insert("wifesfk.insert" , w1) ;
39 
40         sess.commit();
41         sess.close();
42         System.out.println("插入成功！");
43     }
44 
45 
46     /**
47      * 测试查询
48      */
49     @Test
50     public void testSelectOne() throws Exception {
51         InputStream in = Resources.getResourceAsStream("mybatis-config.xml");
52         SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(in);
53         SqlSession sess = sf.openSession();
54         Husband husband = (Husband) sess.selectOne("husbandsfk.selectOne", 1);
55         System.out.println(husband.getHname());
56         sess.commit();
57         sess.close();
58     }
59 }

　　运行以上代码查看数据库内容如下：

查看全文

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原文地址：https://www.cnblogs.com/yinzhengjie/p/9287302.html