想飞的鱼 Java Dev Engineer

常用代码片段

2021-09-23

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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