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Yesterday, the product put forward an urgent demand to export the commodity data shipped in November, write SQL and send it to DBA for execution, and then get more than 30 Excel files of 100W data. There is a property that exists in a field in the table in JSON format. You need to process the excel f ...

According to the different levels of abstraction, factory pattern can be divided into three types: simple factory pattern (also known as static factory pattern), factory method pattern described in this paper, and abstract factory pattern. Advantages of factory mode: It can make the code structure cle ...

order This paper mainly studies carrera's rocket MQ procedure offset fetcher RocketMQProduceOffsetFetcher DDMQ/carrera-monitor/src/main/java/com/xiaojukeji/carrera/monitor/lag/offset/RocketMQProduceOffsetFetcher.java public class RocketMQProduceOffsetFetcher { private static final Logger LOGGER = LoggerFactory.getLogger(RocketMQProduceOffse ...

brief introduction Of course, there is nothing to say about regular window functions. It's very simple. Here's an introduction to grouping, focusing on the usage of rows between after grouping and sorting. The key is to understand the meaning of keywords in rows between: Keyword Meaning preceding Forward following In the future current ...

Two entities: order and commodity. An order can contain multiple commodities, and a commodity can belong to multiple orders, that is, many to many.   Goods table     Order form TB: no is the order number, and the user "id is associated with the id of the user table.     You need to create a new intermediate table, order item TB, and intr ...

First of all, a question is raised. Why do we separate the jar package? The reason is very simple. The jar files that we use the spring boot maven plugin plug-in to package are usually large, or tens of meters less. If the external network transmission of the upload cloud server is slow, why the files will be large after packaging? This is bec ...

//Original link: https://www.baidu.com/benefit_detail?slug=bankofchina-20170320 //Target link: https://www.test.cn/boc location ~ /benefit_detail { if ($args ~* "slug=bankofchina-20170320") { rewrite ^/benefit_detail /boc? permanent; } try_files $uri $uri/ /index.php?$query_string; } Common jump ca ...

Summary XPopupWindow, which further encapsulates and strengthens the PopupWindow of the system for easy use. With Kotlin language, many additional functions are provided, such as setting the position of the pop-up window, adjusting the animation of the pop-up window and so on. Project address XPopupWindow preview C ...

redis is turned off by default. It is not recommended to turn it on. This paper provides a reference. Key space notification is usually not enabled because of the additional cost of this process. 1. Enable redis configuration # # notify-keyspace-events Ex # # By default all notifications are disabled because most users don't need # th ...

After checking the usage of JMH, many blogs have to be very complicated. This step is quite simple for me Using Intellij IDEA2018.2 as the integrated development environment, JMH version is 1.21 Note that when building a project, you must create a maven project and directly import the two jar s, jmh core and jmh generator ann ...