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06-mybatis的多表操作-多对多配置实现

发布时间：2025-02-02 12:28:15编辑：雪饮阅读（）

基于上篇现在建立Role.java如：
package sp28.domain;

public class Role {
    private int id;
    private String roleName;
    private String roleDesc;

    public int getId() {
        return id;
    }

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

    public String getRoleName() {
        return roleName;
    }

    public void setRoleName(String roleName) {
        this.roleName = roleName;
    }

    public String getRoleDesc() {
        return roleDesc;
    }

    public void setRoleDesc(String roleDesc) {
        this.roleDesc = roleDesc;
    }

    @Override
    public String toString() {
        return "Role{" +
                "id=" + id +
                ", roleName='" + roleName + '\'' +
                ", roleDesc='" + roleDesc + '\'' +
                '}';
    }
}
然后User.java中新增roleList属性并生成getter和setter，并重新编写toString方法
package sp28.domain;

import java.util.Date;
import java.util.List;

public class User {

    private int id;
    private String username;
    private String password;
    private Date birthday;
    private List<Order> orderList;
    private List<Role> roleList;

    public List<Role> getRoleList() {
        return roleList;
    }

    public void setRoleList(List<Role> roleList) {
        this.roleList = roleList;
    }

    public List<Order> getOrderList() {
        return orderList;
    }

    public void setOrderList(List<Order> orderList) {
        this.orderList = orderList;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }



    public int getId() {
        return id;
    }

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

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", birthday=" + birthday +
                ", orderList=" + orderList +
                ", roleList=" + roleList +
                '}';
    }
}
然后UserMapper.java中新增查询用户并每个用户都包含其角色列表的抽象方法
package sp28.dao;

import sp28.domain.User;

import java.util.List;

public interface UserMapper {
    public List<User> findAll();
    public List<User> findUserAndRoleAll();
}
sqlMapConfig.xml中要定义role类型别名，因为我要用别名去定义findUserAndRoleAll的实现中调用。
<?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>
    <properties resource="jdbc.properties"/>

    <typeAliases>
        <typeAlias type="sp28.domain.User" alias="user"/>
        <typeAlias type="sp28.domain.Order" alias="order"/>
        <typeAlias type="sp28.domain.Role" alias="role"/>
    </typeAliases>

    <typeHandlers>
        <typeHandler handler="sp28.handler.DateTypeHandler"/>
    </typeHandlers>
    <plugins>
        <plugin interceptor="com.github.pagehelper.PageHelper">
            <property name="dialect" value="mysql"/>
        </plugin>
    </plugins>
    <environments default="developement">
        <environment id="developement">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"/>
                <property name="url" value="${jdbc.url}"/>
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>
            </dataSource>
        </environment>
    </environments>
   

    <mappers>
        <mapper resource="sp28/mapper/UserMapper.xml"></mapper>
        <mapper resource="sp28/mapper/OrderMapper.xml"></mapper>
    </mappers>

</configuration>
然后在UserMapper.xml中去定义findUserAndRoleAll的实现
<?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="sp28.dao.UserMapper">
    <resultMap id="userMap" type="user">
        <!--
        column：数据表的字段名称
        property:实体的属性名称
        -->
        <id property="id" column="id"/>
        <result property="username" column="username"/>
        <result property="password" column="password"/>
        <result property="birthday" column="birthday"/>
        <!--
        配置集合信息
        property：集合名称
        ofType: 集合中元素的数据类型
        -->
        <collection property="orderList" ofType="order">
            <!--封装order的数据-->
            <id property="id" column="oid"/>
            <result column="ordertime" property="ordertime"/>
            <result column="total" property="total"/>
        </collection>
    </resultMap>
    <select id="findAll" resultMap="userMap">
        select *,o.id oid from user u,orders o where u.id=o.uid
    </select>
    <resultMap id="userRoleMap" type="user">
        <!--
       column：数据表的字段名称
       property:实体的属性名称
       -->
        <!--user信息-->
        <id column="userId" property="id"/>
        <result column="username" property="username"/>
        <result column="password" property="password"/>
        <result column="birthday" property="birthday"/>
        <!--user内部的roleList信息-->
        <collection property="roleList" ofType="role">
            <id column="roleId" property="id"/>
            <result column="roleName" property="roleName"/>
            <result column="roleDesc" property="roleDesc"/>
        </collection>
    </resultMap>
    <select id="findUserAndRoleAll" resultMap="userRoleMap">
        select * from user u,sys_user_role ur,sys_role r where u.id=ur.userId and ur.roleId=r.id
    </select>
</mapper>
最后编写测试方法test3于MapperTest.java中
package sp28;

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.Test;
import sp28.dao.OrderMapper;
import sp28.dao.UserMapper;
import sp28.domain.Order;
import sp28.domain.User;

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

public class MapperTest {
    @Test
    public void test1() throws IOException {
        InputStream resourceAsStream= Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession=sqlSessionFactory.openSession();
        OrderMapper mapper=sqlSession.getMapper(OrderMapper.class);
        List<Order> orderList=mapper.findAll();
        for (Order order : orderList) {
            System.out.println(order);
        }
        sqlSession.close();
    }
    @Test
    public void test2() throws IOException {
        InputStream resourceAsStream= Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession=sqlSessionFactory.openSession();
        UserMapper mapper=sqlSession.getMapper(UserMapper.class);
        List<User> userList=mapper.findAll();
        for (User user : userList) {
            System.out.println(user);
        }
        sqlSession.close();
    }
    @Test
    public void test3() throws IOException {
        InputStream resourceAsStream= Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession=sqlSessionFactory.openSession();
        UserMapper mapper=sqlSession.getMapper(UserMapper.class);
        List<User> userList=mapper.findUserAndRoleAll();
        for (User user : userList) {
            System.out.println(user);
        }
        sqlSession.close();
    }
}