• [case50] talk about fscheckpointstorage in flick


    order This paper mainly studies fscheckpoint storage of Flink CheckpointStorage flink-runtime_2.11-1.7.0-sources.jar!/org/apache/flink/runtime/state/CheckpointStorage.java /** * CheckpointStorage implements the durable storage of checkpoint data and metadata streams. * An individual checkpoint or savepoint is stored to a {@link CheckpointStorageLocation}, * created by this class. */ public interface CheckpointStorage { boolean supportsHighlyAvailableStorage(); boolean hasDefaultSavepointLocation(); CompletedCheckpointStorageLocation resolveCheckpoint(String externalPointer) throws IOException; […]

  • WPF’s road to customs clearance


    First of all, I would like to explain two points. First, I am interested in desktop development (it is not recommended to learn client-side development simply by looking for a job). Second, the style of WPF is much better than WinForm (because customization is very free). Basically, except for 3D images and related animation effects, […]

  • Math class


    summary Java.lang.math class package, which executes basic mathematical operation methods method Return absolute valuedouble s = Math.ceil(-5);//5 The integer becomes larger and the negative becomes smallerdouble d2 = Math.ceil(3.5);//4 The integer becomes smaller and the negative becomes larger double d3 =Math.floor(3.5);//3 roundingdouble d4 =Math.round(4.5);//5

  • Fetch API


    Fetch API One of the deepest secrets is the underlying of Ajax implementationXMLHttpRequest, this method was not made to do this. There are many elegant API wrappers for XHR, but that’s not enough. So there wasfetchAPI。 Let’s take a look at the basic usage of this API. The latest browsers already support this method. XMLHttpRequest […]

  • (process management) 01. Processes and threads


    Process: Process is the basic unit of system resource allocation and independent operation. The creation, scheduling, running and destruction of processes are controlled by the operating system. The operating system will be responsible for switching the state of the process, which is the management of the process. A process creates a process. The former is […]

  • Bye, docker! 5 minutes to transform containerd!


    Docker, as a very popular container technology, has been abandoned by k8s and replaced by another container technology containerd! In fact, containerd is only a bottom container separated from docker. When it is used, it is no different from docker. This article mainly introduces the use of containerd, hoping to help you! Springboot e-commerce project […]

  • Design mode – 17) combination mode


    abstract class Component { protected string name; public Component(string name) { this.name = name; } public abstract void Add(Component c); public abstract void Remove(Component c); public abstract void Display(int depth); } class Leaf : Component { public Leaf(string name) : base(name) { } public override void Add(Component c) { Console.WriteLine(“Leaf cannot add”); } public override […]

  • Mybatis single table addition, deletion, modification, query and extraction


    In daily development, we can extract or use mybatis plus for the addition, deletion, modification and query of mybatis single table Extract public Dao interface public interface IBaseDao<T> { int deleteByPrimaryKey(Long id); int insert(T t); int insertSelective(T t); T selectByPrimaryKey(Long id); int updateByPrimaryKeySelective(T t); int updateByPrimaryKey(T t); } Extract public service public interface IBaseService<T> { […]

  • 003 add functions to the linked list by learning rust from the linked list


    introduce Video address:www.bilibili.com/video/av78062009/Relevant source code:github.com/anonymousGiga/Rust-link… Details In the previous section, we basically determined the layout of the linked list. Next, we will implement the response function of the linked list. For linked lists, the most basic functions are: The new // new function is a function that creates a linked list Push // function for […]

  • Rust bit by bit: one stop learning standard library (1) – how to start


    motivation An excellent programming language should not only have basic language specifications, but also be supported by high-quality standard library. Rust provides a set of standard library to broaden the ecology of rust. The standard library provides common core types, collections, multithreading, macros and other tools, so that it is convenient to use rust for […]

  • Map in mybatis


    Assuming that there are too many entity classes or tables, fields or parameters in the database, we should use map! User addUser(Map<String,Object> map); <!– The properties of the object can be retrieved directly Pass key of map –> <insert id=”addUser” parameterType=”map”> insert into mybatis.user(id,name,pwd) values (#{userId},#{userName},#{password}); </insert> test @Test public void addUser(){ SqlSession sqlSession = […]

  • Mybatis annotation CRUD


    1、CRUD We can automatically commit transactions when the tool class is created! public class MybatisUtils{ private static SqlSessionFactory sqlSessionFactory; static{ try{ //Step 1 of using mybatis: get sqlsessionfactory object String resource = “mybatis-config.xml”; InputStream inputStream = Resources.getResourceAsStream(resource); sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); }catch(IOException e){ e.printStackTrace(); } } public static sqlSession getSqlSession(){ return sqlSessionFactory.openSession(true); } } 2. […]