Mybatis中使用association及collection进行一对多双向关联示例（含XML版与注解版）

XML版本：

实体类：

package com.sunwii.mybatis.bean;

import java.util.ArrayList;

import java.util.List;

import lombok.Data;

import lombok.NoArgsConstructor;

import lombok.ToString;

@Data

@ToString

@NoArgsConstructor

public class Dept {

    private Integer id;

    private String name;

    private List<Employee> employees = new ArrayList<Employee>();

    public Dept(Integer id) {

        this.id = id;

    }

    public String toLazyString() {

        return "Dept:{id: "+this.id+" ; name: "+this.name+"}";

    }

}

package com.sunwii.mybatis.bean;

import lombok.Data;

import lombok.NoArgsConstructor;

@Data

@NoArgsConstructor

public class Employee {

    protected Integer id;

    protected String name;

    protected Dept dept;

    public Employee(Integer id) {

        this.id = id;

    }

    public String toLazyString() {

        return "Employee:{id: " + this.id + "; name: " + this.name + "}";

    }

    @Override

    public String toString() {

        return "Employee(id=" + this.id + ", name=" + this.name + ", dept={id=" + this.dept.getId() + ", name="

                + this.dept.getName() + "})";

    }

}

Mapper接口：

package com.sunwii.mybatis.mapper;

import com.sunwii.mybatis.bean.Dept;

public interface DeptMapper {

    public Dept selectById(Integer id);

    public int insertDept(Dept dept);

    public int updateDept(Dept dept);

    public int deleteDept(Dept dept);

}

package com.sunwii.mybatis.mapper;

import com.sunwii.mybatis.bean.Employee;

public interface EmployeeMapper {

    public Employee selectById(Integer id);

    public int insertEmployee(Employee employee);

    public int updateEmployee(Employee employee);

    public int deleteEmployee(Employee employee);

}

Mapper映射文件：

<?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="com.sunwii.mybatis.mapper.DeptMapper">

    <resultMap type="Dept" id="DeptMap_basic">

        <id property="id" column="did" />

        <result property="name" column="name" />

    </resultMap>

    <resultMap type="Dept" id="DeptMap" extends="DeptMap_basic">

         <!-- 一对多关联：使用select引用方式 -->

        <collection property="employees" column="did" ofType="Employee" select="com.sunwii.mybatis.mapper.EmployeeMapper.selectByDept" fetchType="lazy">

        </collection>

    </resultMap>

    <select id="selectById" parameterType="Integer"

        resultMap="DeptMap">

        select id as did, name from t_dept d where d.id=#{id}

    </select>

    <insert id="insertDept" parameterType="Dept" keyColumn="id"

        keyProperty="id" useGeneratedKeys="true">

        insert into t_dept(name)

        values(#{name})

    </insert>

    <update id="updateDept" parameterType="Dept">

        update t_dept set

        name=#{name}

        where id=#{id}

    </update>

    <delete id="deleteDept" parameterType="Dept">

        delete from t_dept

        where

        id=#{id}

    </delete>

</mapper>

<?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="com.sunwii.mybatis.mapper.EmployeeMapper">

    <resultMap type="Employee" id="EmployeeMap_basic">

        <id property="id" column="id" />

        <result property="name" column="name" />

    </resultMap>

    <resultMap type="Employee" id="EmployeeMap" extends="EmployeeMap_basic">

        <!-- 多对一关联：使用select引用方式 -->

        <association property="dept" column="dept_id"

            javaType="Dept"

            select="com.sunwii.mybatis.mapper.DeptMapper.selectById"

            fetchType="lazy" />

    </resultMap>

    <select id="selectById" parameterType="Integer"

        resultMap="EmployeeMap">

        select id, name, dept_id from t_employee e where e.id=#{id}

    </select>

    <select id="selectById2" parameterType="Integer"

        resultMap="EmployeeMap">

        select e.id id, e.name name,d.id did,d.name dname from

        t_employee e

        inner join t_dept

        d on e.dept_id=d.id and e.id=#{id}

    </select>

    <select id="selectByDept" parameterType="Integer"

        resultMap="EmployeeMap_basic">

        select id, name, dept_id from t_employee e where

        e.dept_id=#{dept.id}

    </select>

    <insert id="insertEmployee" parameterType="Employee"

        keyColumn="id" keyProperty="id" useGeneratedKeys="true">

        insert into t_employee(name

        <if test="dept!=null">

            ,dept_id

        </if>

        )

        values(#{name}

        <if test="dept!=null">

            ,#{dept.id}

        </if>

        )

    </insert>

    <update id="updateEmployee" parameterType="Employee">

        update t_employee set

        name=#{name} ,dept_id=#{dept.id}

        where id=#{id}

    </update>

    <delete id="deleteEmployee" parameterType="Employee">

        delete from t_employee

        where id=#{id}

    </delete>

</mapper>

业务层接口实现类：

package com.sunwii.mybatis.service.impl;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

import org.springframework.transaction.annotation.Transactional;

import com.sunwii.mybatis.bean.Dept;

import com.sunwii.mybatis.mapper.DeptMapper;

import com.sunwii.mybatis.service.DeptService;

@Service

public class DeptServiceImpl implements DeptService {

    @Autowired

    private DeptMapper deptMapper;

    @Override

    public Dept getDept(Integer id) {

        return deptMapper.selectById(id);

    }

    @Override

    @Transactional

    public void insertDept(Dept dept) {

        deptMapper.insertDept(dept);

    }

    @Override

    @Transactional

    public void updateDept(Dept dept) {

        deptMapper.updateDept(dept);

    }

    @Override

    @Transactional

    public void deleteDept(Dept dept) {

        deptMapper.deleteDept(dept);

    }

}

package com.sunwii.mybatis.service.impl;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

import org.springframework.transaction.annotation.Transactional;

import com.sunwii.mybatis.mapper.DeptMapper;

import com.sunwii.mybatis.mapper.EmployeeMapper;

import com.sunwii.mybatis.service.EmployeeService;

import com.sunwii.mybatis.bean.*;

@Service

public class EmployeeServiceImpl implements EmployeeService {

    @Autowired

    private EmployeeMapper employeeMapper;

    @Autowired

    private DeptMapper deptMapper;

    @Override

    public Employee getEmployee(Integer id) {

        return employeeMapper.selectById(id);

    }

    @Override

    @Transactional

    public void insertEmployee(Employee employee) {

        Dept dept = employee.getDept();

        //如果需要的话，就先新增部门

        if(dept!=null && dept.getId()==null) {

            deptMapper.insertDept(dept);

        }

        employeeMapper.insertEmployee(employee);

    }

    @Override

    @Transactional

    public void updateEmployee(Employee employee) {

        employeeMapper.updateEmployee(employee);

    }

    @Override

    @Transactional

    public void deleteEmployee(Employee employee) {

        employeeMapper.deleteEmployee(employee);

    }

}

Spring配置文件：

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:context="http://www.springframework.org/schema/context"

    xmlns:p="http://www.springframework.org/schema/p"

    xmlns:aop="http://www.springframework.org/schema/aop"

    xmlns:tx="http://www.springframework.org/schema/tx"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xmlns:mybatis="http://mybatis.org/schema/mybatis-spring"

    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd

    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd

    http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd

    http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.0.xsd

    http://mybatis.org/schema/mybatis-spring http://mybatis.org/schema/mybatis-spring.xsd">

    <!-- 引入jdbcs配置文件 -->

    <context:property-placeholder

        location="classpath:jdbc.properties" />

    <!-- 数据库连接池 -->

    <bean id="dataSource"

        class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">

        <property name="driverClassName" value="${driver}" />

        <property name="url" value="${url}" />

        <property name="username" value="${user}" />

        <property name="password" value="${password}" />

        <property name="maxActive" value="210" />

        <property name="maxIdle" value="50" />

    </bean>

    <!-- mybatis -->

    <bean id="sessionFactory"

        class="org.mybatis.spring.SqlSessionFactoryBean">

        <property name="dataSource" ref="dataSource" />

        <property name="configLocation"

            value="classpath:mybatis-config.xml" />

        <property name="mapperLocations"

            value="classpath:com/sunwii/mybatis/bean/*.xml" />

    </bean>

    <!-- Mapper动态代理开发扫描 -->

    <mybatis:scan base-package="com.sunwii.mybatis.mapper" />

    <!-- 事务管理器 -->

    <bean id="transactionManager"

        class="org.springframework.jdbc.datasource.DataSourceTransactionManager">

        <property name="dataSource" ref="dataSource" />

    </bean>

    <!-- 事务注解 -->

    <tx:annotation-driven

        transaction-manager="transactionManager" />

    <!-- 组件扫描 -->

    <!-- Service扫描 -->

    <context:component-scan

        base-package="com.sunwii.mybatis.service.impl" />

</beans>

Mybatis配置文件：

<?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>

    <settings>

        <setting name="lazyLoadingEnabled" value="true" />

        <setting name="aggressiveLazyLoading" value="false" />

    </settings>

    <typeAliases>

        <package name="com.sunwii.mybatis.bean" />

    </typeAliases>

</configuration>

测试类：

package com.sunwii.mybatis.test.one2many;

import org.junit.Test;

import org.springframework.context.ApplicationContext;

import com.sunwii.mybatis.bean.Dept;

import com.sunwii.mybatis.bean.Employee;

import com.sunwii.mybatis.service.DeptService;

import com.sunwii.mybatis.service.EmployeeService;

import com.sunwii.mybatis.util.SpringUtil;

public class TestOne2Many {

    private ApplicationContext context = SpringUtil.getContext();

    private EmployeeService employeeService = (EmployeeService)context.getBean(EmployeeService.class);

    private DeptService deptService = (DeptService)context.getBean(DeptService.class);

    @Test

    public void testEmployeeInsert() {

        // 多对一：添加。

        Employee employee = new Employee();

        employee.setName("e-1");

        Dept dept = deptService.getDept(1);

        employee.setDept(dept);

        employeeService.insertEmployee(employee);

    }

    @Test

    public void testEmployeeInsert2() {

        // 多对一：添加。

        Employee employee = new Employee();

        employee.setName("e-2");

        //Dept dept = deptService.getDept(1);

        //employee.setDept(dept);

        employeeService.insertEmployee(employee);

    }

    @Test

    public void testEmployeeSelect() {

        // 多对一：查询。

        int id = 16;

        Employee employee = employeeService.getEmployee(id);

        System.out.println(employee.toLazyString());

        System.out.println(employee);

    }

    @Test

    public void testEmployeeUpdate() {

        // 多对一：更新。

        int id = 15;

        Employee employee = employeeService.getEmployee(id);

        employee.setName("eeeeeeeeeeeee15");

        employeeService.updateEmployee(employee);

    }

    @Test

    public void testEmployeeDelete() {

        // 多对一：删除。

        int id=15;

        Employee employee = new Employee(id);

        employeeService.deleteEmployee(employee);

    }

    @Test

    public void testDeptSelect() {

        // 一对多：更新。

        int id=1;

        Dept dept = deptService.getDept(id);

        System.out.println(dept.toLazyString());

        System.out.println(dept);

    }

    @Test

    public void testDeptUpdate() {

        // 一对多：更新。

        int id=2;

        Dept dept = new Dept(id);

        dept.setName("ddddddddd2");

        deptService.updateDept(dept);

    }

}

注解版本：

注解版本只是将Mapper映射文件去掉，将映射注解到Mapper接口中（并使用了动态sql提供器），其它东西不变。

Mapper接口（注解版）：

package com.sunwii.mybatis.mapper;

import org.apache.ibatis.annotations.Delete;

import org.apache.ibatis.annotations.Insert;

import org.apache.ibatis.annotations.Many;

import org.apache.ibatis.annotations.Options;

import org.apache.ibatis.annotations.Result;

import org.apache.ibatis.annotations.Results;

import org.apache.ibatis.annotations.Select;

import org.apache.ibatis.annotations.Update;

import org.apache.ibatis.mapping.FetchType;

import com.sunwii.mybatis.bean.Dept;

public interface DeptMapper {

    public static final String select = "select id,name from t_dept where id=#{id}";

    public static final String insert = "insert into t_dept(name) values(#{name})";

    public static final String update = "update t_dept set name=#{name}";

    public static final String delete = "delete from t_dept where id=#{id}";

    public static final String one2many = "com.sunwii.mybatis.mapper.EmployeeMapper.selectByDept";

    @Select(select)

    @Results(id = "DeptMap", value= {

            @Result(property = "id", column = "id"),

            @Result(property = "name", column = "name"),

            @Result(property = "employees", column = "id",

            many = @Many(

                    select = one2many,

                    fetchType = FetchType.LAZY))

    })

    public Dept selectById(Integer id);

    @Insert(insert)

    @Options(keyColumn = "id", keyProperty = "id", useGeneratedKeys = true)

    public int insertDept(Dept dept);

    @Update(update)

    public int updateDept(Dept dept);

    @Delete(delete)

    public int deleteDept(Dept dept);

}

package com.sunwii.mybatis.mapper;

import java.util.List;

import org.apache.ibatis.annotations.Delete;

import org.apache.ibatis.annotations.InsertProvider;

import org.apache.ibatis.annotations.One;

import org.apache.ibatis.annotations.Options;

import org.apache.ibatis.annotations.Result;

import org.apache.ibatis.annotations.Results;

import org.apache.ibatis.annotations.Select;

import org.apache.ibatis.annotations.Update;

import org.apache.ibatis.mapping.FetchType;

import com.sunwii.mybatis.bean.Employee;

import com.sunwii.mybatis.provider.EmployeeDynamicSqlProvider;

public interface EmployeeMapper {

    public static final String select = "select id,name,dept_id from t_employee where id=#{id}";

    public static final String selectByDept = "select id,name from t_employee where dept_id=#{deptId}";

    public static final String insert = null;// dynamic sql provider

    public static final String update = "update t_employee set name=#{name},dept_id=#{dept.id}";

    public static final String delete = "delete from t_employee where id=#{id}";

    public static final String many2one = "com.sunwii.mybatis.mapper.DeptMapper.selectById";

    @Select(select)

    @Results(id="EmployeeMap", value= {

            @Result(property = "id",column = "id"),

            @Result(property = "name", column = "name"),

            @Result(property = "dept",column = "dept_id",

                one = @One(

                        select = many2one,

                        fetchType = FetchType.LAZY))

    })

    public Employee selectById(Integer id);

    @Select(selectByDept)

    @Results(id="EmployeeMap_basic", value= {

            @Result(property = "id",column = "id"),

            @Result(property = "name", column = "name")

    })

    public List<Employee> selectByDept(Integer deptId);

    @InsertProvider(type = EmployeeDynamicSqlProvider.class, method = "insert")

    @Options(keyColumn = "id", keyProperty = "id", useGeneratedKeys = true)

    public int insertEmployee(Employee employee);

    @Update(update)

    public int updateEmployee(Employee employee);

    @Delete(delete)

    public int deleteEmployee(Employee employee);

}

动态SQL提供器:

package com.sunwii.mybatis.provider;

import org.apache.ibatis.jdbc.SQL;

import com.sunwii.mybatis.bean.Employee;

public class EmployeeDynamicSqlProvider {

    private SQL NOTNULLSET(String columnAndValue, SQL sqlObject, Object object) {

        if(object!=null) {

            return sqlObject.SET(columnAndValue);

        }

        return sqlObject;

    }

    private SQL NOTNULLVALUES(String column, String value, SQL sqlObject, Object object) {

        if(object!=null) {

            return sqlObject.VALUES(column,value);

        }

        return sqlObject;

    }

    public String insert(Employee employee) {

        return new SQL() {

            {

                INSERT_INTO("t_employee");

                VALUES("name", "#{name}");

                NOTNULLVALUES("dept_id","#{dept.id}",this, employee.getDept());

            }

        }.toString();

    }

}

多对多的示例：

https://www.cnblogs.com/dreamyoung/p/11804936.html

巴特西

Mybatis中使用association及collection进行一对多双向关联示例（含XML版与注解版）

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