mybatis之一对一关联

 

 

MapperAsso.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="bean.User">
    <!--一对一关联-->
    <select id="selectOneAssoObj" parameterType="int" resultMap="OneAssoObjRM">
        select * from user where id = #{id}
    </select>
    <resultMap type="association.AssoObj" id="OneAssoObjRM">
        <result property="id" column="id"/>
        <result property="name" column="name"/>
        <result property="age" column="age"/>
        <association  property="salary" column="name" select="selectOneSalary"/>
        <!--一对多关联配置备注-->
        <!--<collection property="salarys" ofType="bean.Salary" column="name" select="selectFewSalarys">-->
    </resultMap>

    <select id="selectOneSalary" parameterType="String" resultType="bean.Salary">
        select * from salary where name = #{name}
    </select>

    <!--id：名称； parameterType传入参数类型； resultType：返回数据类型-->
    <select id="selectOneUser" parameterType="int" resultType="bean.User">
        select * from user where id = #{id}
    </select>

    <!--批量查询-->
    <select id="selectAllUser" resultMap="userList">
        select * from user
    </select>
    <resultMap type="first.UserBean" id="userList">
        <result property="id" column="id"/>
        <result property="name" column="name"/>
        <result property="age" column="age"/>
    </resultMap>


</mapper>

 

AssoObj.java

package association;

import bean.Salary;

/**
 * 数据封装类
 * user class with Salary object
 * 一对一关联Javabean
 */
public class AssoObj {
    private int id;
    private String name;
    private String age;
    private Salary salary;

    public AssoObj() {

    }

    public AssoObj(String name, String age) {
        this.name = name;
        this.age = age;
    }

    public AssoObj(int id, String name, String age, Salary salary) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.salary = salary;
    }

    public String getName() {
        return name;
    }

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

    public String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age;
    }

    public int getId() {
        return id;
    }

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

    public Salary getSalary() {
        return salary;
    }

    public void setSalary(Salary salary) {
        this.salary = salary;
    }

    @Override
    public String toString() {
        return "AssoObj{id：" + id + "; 姓名：" + name +
                "; 年龄：" + age + "; Salary对象：" + salary + "}";
    }
}

 

TestAsso.java

package association;

import bean.Salary;
import bean.User;
import bean.UserSalary;
import first.UserBean;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Ignore;
import org.junit.Test;
import zhujie.UserMapperInterface;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

/*
* 一对一关联举例
*
* */
public class TestAsso {
    String resource = "mybatis-config-assosciation.xml";
    SqlSessionFactory sqlSessionFactory = null;
    SqlSession session = null;

    @Before
    public void before() {
//        System.out.println("Before");
        try {
            InputStream inputStream = Resources.getResourceAsStream(resource);
//            创建工厂
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//            创建session对象
            session = sqlSessionFactory.openSession();

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @After
    public void close() {
        session.close();
//        System.out.println("After");
    }

    //    一对一关联测试用例
    @Test
    public void testSelectOneAssoObj() {
        AssoObj assoObj = session.selectOne("bean.User.selectOneAssoObj", 1);
        System.out.println("查询单个AssoObj：" + assoObj);
    }

    @Test
    public void testSelectOneUser() {
        User user = session.selectOne("bean.User.selectOneUser", 1);
        System.out.println("查询单个User：" + user);
    }

    @Test
    public void testSelectAllUser() {
        List<User> listUser = session.selectList("bean.User.selectAllUser");
        System.out.println("记录个数：" + listUser.size());
        System.out.println(listUser);
    }

    @Test
    public void testSelectOneSalary() {
        Salary salary = session.selectOne("bean.User.selectOneSalary", "Tom");
        System.out.println("查询单个Salary：" + salary);
    }


}

 

mybatis-config-assosciation.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!--从外部配置文件导入jdbc信息-->
    <properties resource="jdbc.properties"></properties>

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>

    <!--指定映射资源文件-->
    <mappers>
        <mapper resource="association/MapperAsso.xml"/>

    </mappers>
</configuration>