Programmer Group

Subscription publishing mode The subscription publication pattern defines a one to many dependency, allowing multiple subscriber objects to listen to a topic object at the same time. When the subject object changes its state, it will notify all subscriber objects so that they can automatically update their state. Dividing a system int ...

1. C3P0 database connection pool Information: link: https://pan.baidu.com/s/19jWfIQ_OlZ29pPPnxNm5og Extraction code: hgha 1.1 concept In fact, it is a container (Collection) for storing database connections.After the system is initialized, the container is created, and some connection objects will be applied in the container. When the user a ...

Chapter I Stream flow 1.1 INTRODUCTION (1) Multi step traversal code of traditional collection Almost all collections (such as Collection interface or Map interface) support direct or indirect traversal operations. When we need to operate on the elements in the Collection, in addition to the necessary addition, deletion and acquisitio ...

1, TiDB Binlog In the previous article, we introduced the use of TiDB Binlog to synchronize data to downstream Mysql. In this article, we learn to use TiDB Binlog tool to synchronize data to custom business logic in Kafka. For example, TIDB can synchronize data with ES, MongoDB or Redis. This function is not different from the binlog function ...

preface I've been blogging for some time. Most of the previous articles are about what to use in work and what to write. They have no purpose. Recently, I've been thinking about filling in the pits left during learning, such as java reflection and dynamic agent. I only remember when I was learning. The teacher said that this was the key point ...

Original link https://llfc.club/category?catid=20RbopkFO8nsJafpgCwwxXoCWAs#!aid/21lVoQbhTZo83drdNp10Iv2WOfc Objectives of this section In the previous section, we added the routing of the home page and the html template of the home page. In this section, we return a template with parameter rendering, add the load data from the database to the h ...

1, Traversal of binary tree Access each node in the tree according to a search path, so that each node is accessed. It is mainly divided into first order traversal, middle order traversal, second order traversal and sequence traversal 2, Preorder traversal 2.1 manual calculation The exam usually gives the shape of a tree and writes its preo ...

1, Dynamic SQL Official website: https://mybatis.org/mybatis-3/zh/dynamic-sql.html Dynamic SQL is one of the powerful features of MyBatis. If you have used JDBC or other similar frameworks, you should be able to understand how painful it is to splice SQL statements according to different conditions. For example, when splicing, make sure you c ...

Great! Someone introduced Ansible Playbook like this! After a series of basic training and honing, it finally came to the application of relatively tall. (Nani is just starting to review his future: https://blog.csdn.net/qq_41765918/category_11512932.html) 1. What is playbook Chinese Name: script, which is an automatic processing script. P ...

Introduction: Through the array mem in micropthon, the internal analog comparator of MM32F3277 is preliminarily tested to verify its most basic setting and working relationship. During the test, problems in the data manual and corresponding internal functions of MM32F3277 were also found: wrong description of COMP Control Register Offset and ho ...