常用代码片段

mysql

• 添加索引

  # 添加唯一索引
  alter table t_device_record add UNIQUE uq_fieldid(file_id) 
  

mybatis

• 批量插入

  
  <insert id="insertBatch"  parameterType="java.util.List" useGeneratedKeys="true" keyProperty="id">
      insert into t_device_record (id, title, user_id)
      values
      <foreach collection="datas" item="item" index="index"  separator=","  >
        (
          #{item.id,jdbcType=BIGINT}, #{item.title,jdbcType=VARCHAR}, #{item.userId,jdbcType=BIGINT}
        )
      </foreach>
    </insert>

• in 查询

  <select id="getByFileIds" parameterType="java.util.List" resultMap="BaseResultMap">
      select
      <include refid="Base_Column_List" />
      from t_device_record
      where file_id in  (
        <foreach collection="fileIds" item="fileId" index="index"  separator=","  >
          #{fileId}
        </foreach>
      )
    </select>

• 批量插入或修改 (on duplicate key)

  <insert id="insertBatch"  parameterType="java.util.List" useGeneratedKeys="true" keyProperty="id">
      insert into t_device_record (id, title, user_id)
      values
      <foreach collection="datas" item="item" index="index"  separator=","  >
        (
          #{item.id,jdbcType=BIGINT}, #{item.title,jdbcType=VARCHAR}, #{item.userId,jdbcType=BIGINT}
        )
      </foreach>
      on duplicate key update
      id = VALUES(id),
      title = VALUES(title)
  </insert>
  
  

java

• stream流获取list中某属性集合

  //获取属性列表
  List<Long> fileIds = items.stream().map(FeedbackAnalyzeItemOutVo::getFileId).collect(Collectors.toList());
  //获取属性列表

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