Twelve, MyBatis for batch processing

In this section, learn to use collections to save batch data, and then use batch sql (use foreach to traverse) to batch data at one time

One, batch add

xml configuration

<!--    INSERT INTO table-->
<!--    VALUES ("a1","a2","a3"),("b1","b2","b3"),(...)-->
<!--批量新增-->
<!--因为批处理是一次性导入多条，所以这里使用list-->
<!--foreach类似for循环 collection：迭代的数据源，固定写入list，表示从外界传入的list集合 ，item；循环中的迭代变量
，item：索引，类似于数字，seperator：分割符号-->
<insert id="batchInsert" parameterType="java.util.List">
    insert into t_goods(title,sub_title,original_cost,current_price,discount,is_free_delivery,category_id)
    values
    <foreach collection="list" item="item" index="index" separator=",">
        (#{item.title},#{item.subTitle},#{item.originalCost},#{item.currentPrice},#{item.discount},#{item.isFreeDelivery},#{item.categoryId})
    </foreach>
</insert>

test

@Test
public void testBatchInsert() {
    
    
    SqlSession sqlSession = null;
    try {
    
    
        sqlSession = MyBatisUtils.openSession();
        List<Goods> good = new ArrayList<>();
        for (int i = 0; i < 10000; i++) {
    
    
            Goods goods = new Goods();
            goods.setTitle("测试商品6");
            goods.setSubTitle("测试商品666");
            goods.setCategoryId(111);
            goods.setOriginalCost(1000f);
            goods.setIsFreeDelivery(1);
            goods.setDiscount(2f);
            goods.setCurrentPrice(300f);
            good.add(goods);
        }
        sqlSession.insert("goods.batchInsert",good);
        sqlSession.commit();
    } catch (Exception e) {
    
    
        if (sqlSession != null) {
    
    
            sqlSession.rollback();
        }
        throw e;
    } finally {
    
    
       MyBatisUtils.closeSqlSession(sqlSession);
    }
}

Two, batch delete

xml configuration

<!-- DELETE FROM table where goods_id in(a,b)-->
<!--批量删除-->
<!--这里只需要传入item即可，因为它只是goods编号-->
<!--open和close指代删除语句in后面的左右括号-->
<delete id="batchDelete" parameterType="java.util.List">
    delete from t_goods where goods_id in
    <foreach collection="list" item="item" index="index" open="(" close=")" separator=",">
        (#{item})
    </foreach>
</delete>

test

@Test
public void testBatchDelete() {
    
    
    SqlSession sqlSession = null;
    try {
    
    
        sqlSession = MyBatisUtils.openSession();
        List<Integer> good = new ArrayList<>();
        good.add(10000);
        good.add(10001);
        sqlSession.delete("goods.batchDelete",good);
        sqlSession.commit();
    } catch (Exception e) {
    
    
        if (sqlSession != null) {
    
    
            sqlSession.rollback();
        }
        throw e;
    } finally {
    
    
        MyBatisUtils.closeSqlSession(sqlSession);
    }
}

Three, the limitations of batch inserting data

Unable to get the id of the inserted data, if you want to do the subsequent processing through the id, it is not appropriate
The sql generated in batch is too long and may be rejected by the server (solution: you can use segmentation, for example, if you want to import 100w data, you can complete the second nesting of for loop, import 1w at a time)

Twelve, MyBatis for batch processing

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