CREATE TABLE `people` (
  `id` bigint(8) NOT NULL AUTO_INCREMENT,
  `first_name` varchar(50) NOT NULL DEFAULT '',
  `last_name` varchar(50) NOT NULL DEFAULT '',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4

//初始化10w數(shù)據(jù)
@Test
void init10wData() {
    for (int i = 0; i < 100000; i++) {
        People people = new People();
        people.setFirstName(UUID.randomUUID().toString());
        people.setLastName(UUID.randomUUID().toString());
        peopleDAO.insert(people);
    }
}

<!-- 批量更新第一種方法，通過接收傳進(jìn)來的參數(shù)list進(jìn)行循環(huán)組裝sql -->
<update id="updateBatch" parameterType="java.util.List">
    <foreach collection="list" item="item" index="index" open="" close="" separator=";">
        update people
        <set>
            <if test="item.firstName != null">
                first_name = #{item.firstName,jdbcType=VARCHAR},
            </if>
            <if test="item.lastName != null">
                last_name = #{item.lastName,jdbcType=VARCHAR},
            </if>
        </set>
        where id = #{item.id,jdbcType=BIGINT}
    </foreach>
</update>

<!-- 批量更新第二種方法，通過 case when語句變相的進(jìn)行批量更新 -->
<update id="updateBatch2" parameterType="java.util.List">
    update people
    <set>
        <foreach collection="list" item="item">
            <if test="item.firstName != null">
                first_name = case when id = #{item.id} then #{item.firstName} else first_name end,
            </if>
            <if test="item.lastName != null">
                last_name = case when id = #{item.id} then #{item.lastName} else last_name end,
            </if>
        </foreach>
    </set>
    where id in
    <foreach collection="list" item="item" separator="," open="(" close=")">
        #{item.id}
    </foreach>
</update>

<!-- 批量更新第三種方法，通過 replace into  -->
<update id="updateBatch3" parameterType="java.util.List">
    replace into people
    (id,first_name,last_name) values
    <foreach collection="list" index="index" item="item" separator=",">
        (#{item.id},
        #{item.firstName},
        #{item.lastName})
    </foreach>
</update>

<!-- 批量更新第四種方法，通過 duplicate key update  -->
<update id="updateBatch4" parameterType="java.util.List">
    insert into people
    (id,first_name,last_name) values
    <foreach collection="list" index="index" item="item" separator=",">
        (#{item.id},
        #{item.firstName},
        #{item.lastName})
    </foreach>
    ON DUPLICATE KEY UPDATE
    id=values(id),first_name=values(first_name),last_name=values(last_name)
</update>

default boolean updateBatchById(Collection<T> entityList) {
    return this.updateBatchById(entityList, 1000);
}
boolean updateBatchById(Collection<T> entityList, int batchSize);

/**
 * PeopleDAO繼承基類
 */
@Mapper
@Repository
public interface PeopleDAO extends MyBatisBaseDao<People, Long> {

    void updateBatch(@Param("list") List<People> list);

    void updateBatch2(List<People> list);

    void updateBatch3(List<People> list);

    void updateBatch4(List<People> list);
}

@SpringBootTest
class PeopleMapperTest {
    @Resource
    PeopleMapper peopleMapper;
    @Resource
    PeopleService peopleService;
    @Resource
    JdbcTemplate jdbcTemplate;

    @Test
    void init10wData() {
        for (int i = 0; i < 100000; i++) {
            People people = new People();
            people.setFirstName(UUID.randomUUID().toString());
            people.setLastName(UUID.randomUUID().toString());
            peopleMapper.insert(people);
        }
    }


    @Test
    void updateBatch() {
        List<People> list = new ArrayList();
        int loop = 100;
        int count = 5000;
        Long maxCost = 0L;//最長耗時
        Long minCost = Long.valueOf(Integer.MAX_VALUE);//最短耗時
        for (int j = 0; j < count; j++) {
            People people = new People();
            people.setId(ThreadLocalRandom.current().nextInt(0, 100000));
            people.setFirstName(UUID.randomUUID().toString());
            people.setLastName(UUID.randomUUID().toString());
            list.add(people);
        }

        Long startTime = System.currentTimeMillis();
        for (int i = 0; i < loop; i++) {
            Long curStartTime = System.currentTimeMillis();
            // peopleMapper.updateBatch4(list);
            // peopleService.updateBatchById(list);
            jdbcTemplateBatchUpdate(list);
            Long curCostTime = System.currentTimeMillis() - curStartTime;
            if (maxCost < curCostTime) {
                maxCost = curCostTime;
            }
            if (minCost > curCostTime) {
                minCost = curCostTime;
            }
        }
        System.out.println(loop + "-" + (System.currentTimeMillis() - startTime) / loop + "-" + minCost + "-" + maxCost );
    }

    private void jdbcTemplateBatchUpdate (List<People> list){
        String sql = "update people set first_name=?,last_name=? where id = ?";
        List<Object[]> params = list.stream().map(item -> new Object[]{item.getFirstName(), item.getLastName(), item.getId()}).collect(Collectors.toList());
        jdbcTemplate.batchUpdate(sql,params);
    }
}