MyBatis 批量操作 XML 实现方式

MyBatis 通过 XML 映射文件实现批量插入(insert)、更新(update)和删除(delete)的完整方案

1. 批量插入(insert)

1.1 单条SQL批量插入(推荐)

<insert id="batchInsert" parameterType="java.util.List">
    INSERT INTO user(name, age, email) VALUES
    <foreach collection="list" item="item" separator=",">
        (#{item.name}, #{item.age}, #{item.email})
    </foreach>
</insert>

1.2 批量插入并返回主键(MySQL)

<insert id="batchInsert" useGeneratedKeys="true" keyProperty="id">
    INSERT INTO user(name, age, email) VALUES
    <foreach collection="list" item="item" separator=",">
        (#{item.name}, #{item.age}, #{item.email})
    </foreach>
</insert>

1.3 批量插入(Oracle特殊语法)

<insert id="batchInsert">
    INSERT ALL
    <foreach collection="list" item="item">
        INTO user(id, name, age, email) 
        VALUES(#{item.id}, #{item.name}, #{item.age}, #{item.email})
    </foreach>
    SELECT 1 FROM DUAL
</insert>

2. 批量更新(update)

2.1 使用CASE WHEN批量更新(MySQL)

<update id="batchUpdate" parameterType="java.util.List">
    UPDATE user
    <trim prefix="SET" suffixOverrides=",">
        <trim prefix="name = CASE" suffix="END,">
            <foreach collection="list" item="item">
                WHEN id = #{item.id} THEN #{item.name}
            </foreach>
        </trim>
        <trim prefix="age = CASE" suffix="END,">
            <foreach collection="list" item="item">
                WHEN id = #{item.id} THEN #{item.age}
            </foreach>
        </trim>
        <trim prefix="email = CASE" suffix="END">
            <foreach collection="list" item="item">
                WHEN id = #{item.id} THEN #{item.email}
            </foreach>
        </trim>
    </trim>
    WHERE id IN
    <foreach collection="list" item="item" open="(" separator="," close=")">
        #{item.id}
    </foreach>
</update>

2.2 批量更新(Oracle)

<update id="batchUpdate" parameterType="java.util.List">
    <foreach collection="list" item="item" open="BEGIN" close=";END;" separator=";">
        UPDATE user SET
            name = #{item.name},
            age = #{item.age},
            email = #{item.email}
        WHERE id = #{item.id}
    </foreach>
</update>

3. 批量删除(delete)

3.1 普通批量删除

<delete id="batchDelete" parameterType="java.util.List">
    DELETE FROM user WHERE id IN
    <foreach collection="list" item="item" open="(" separator="," close=")">
        #{item.id}
    </foreach>
</delete>

3.2 批量删除(Oracle)

<delete id="batchDelete" parameterType="java.util.List">
    <foreach collection="list" item="item" open="BEGIN" close=";END;" separator=";">
        DELETE FROM user WHERE id = #{item.id}
    </foreach>
</delete>

4. 动态批量操作

4.1 动态批量插入(根据条件)

<insert id="dynamicBatchInsert">
    INSERT INTO user(name, age, email) VALUES
    <foreach collection="list" item="item" separator=",">
        <if test="item.name != null and item.email != null">
            (#{item.name}, #{item.age}, #{item.email})
        </if>
    </foreach>
</insert>

4.2 批量更新非空字段

<update id="batchUpdateSelective" parameterType="java.util.List">
    UPDATE user
    <trim prefix="SET" suffixOverrides=",">
        <trim prefix="name = CASE" suffix="END,">
            <foreach collection="list" item="item">
                <if test="item.name != null">
                    WHEN id = #{item.id} THEN #{item.name}
                </if>
            </foreach>
        </trim>
        <trim prefix="age = CASE" suffix="END,">
            <foreach collection="list" item="item">
                <if test="item.age != null">
                    WHEN id = #{item.id} THEN #{item.age}
                </if>
            </foreach>
        </trim>
    </trim>
    WHERE id IN
    <foreach collection="list" item="item" open="(" separator="," close=")">
        #{item.id}
    </foreach>
</update>

5. 最佳实践建议

1. 批量大小控制：每批处理500-1000条数据最佳

2. 事务管理：确保批量操作在一个事务中完成

3. JDBC参数：MySQL添加rewriteBatchedStatements=true

4. 执行器类型：对于大量数据考虑使用ExecutorType.BATCH

5. 错误处理：考虑分批处理，避免单批失败导致全部回滚