• Principle and practice of spark connector reader


    This paper mainly describes how to use spark connector to read Nebula graph data. Introduction to spark connector Spark connector is a data connector of spark, through which you can read and write the external data system. Spark connector consists of two parts: reader and writer. This paper focuses on the introduction of spark connector […]

  • [joking about spring boot] analysis of spring boot initializer


    The article is first official account. Welcome to subscribe. Today, let’s talk about the execution of the spring boot initializer. Spring boot has three ways to define initializers, which are analyzed one by one. 1. Defined inspring.factoriesIn the file, theSpringFactoriesLoaderDiscovery registration (factory loading mechanism) First, let’s customize a class implementationApplicationContextInitializer。 public class DemoInitializer implements ApplicationContextInitializer<ConfigurableApplicationContext> […]

  • Es8 (5) – the method of ending comma


    catalog introduce benefit be careful Es6-es10 learning map introduce Add a trailing comma to the parameters of function definition and function call. This is in theES2015It’s not legal in China. Function definition parameter addition function foo ( bar, baz, ) { … } Function call parameter addition foo(‘123′,’345’,) The trailing comma in the object is […]

  • Golang automatically generates setters and Getters


    A simple go generate tool is made, which is modified from the official go tool stringer to generate setters and getters for structs. The first letter of the field in the structure is readable and writable by default if it is uppercase, and read-only if it is lowercase. You can add the tag of access. […]

  • Vscode regular substitution


    for instance:Before replacement Access-Control-Allow-Credentials: true Access-Control-Allow-Origin: https://movie.douban.com Cache-Control: must-revalidate, no-cache, private Connection: keep-alive Content-Encoding: br Content-Type: application/json; charset=utf-8 Date: Tue, 08 Dec 2020 08:12:04 GMT Expires: Sun, 1 Jan 2006 01:00:00 GMT Keep-Alive: timeout=30 Pragma: no-cache Server: dae Set-Cookie: bid=QfmDsWrTsvE; Expires=Wed, 08-Dec-21 08:12:04 GMT; Domain=.douban.com; Path=/ Strict-Transport-Security: max-age=15552000 Transfer-Encoding: chunked X-Content-Type-Options: nosniff X-DAE-App: talion X-DAE-Instance: […]

  • Use of Uber JVM profiler


    background uber jvm profilerIt is used to collect JVM related indicators in distributed monitoring, such as CPU / memory / Io / GC information install Make sure to install Maven and JDK > = 8, directly MVN clean package java application explain It can be used directly by Java agent deployment use java -javaagent:jvm-profiler-1.0.0.jar=reporter=com.uber.profiling.reporters.KafkaOutputReporter,brokerList=’kafka1:9092′,topicPrefix=demo_,tag=tag-demo,metricInterval=5000,sampleInterval=0 -cp […]

  • High overhead missing index


    select c.unique_ The number of compilations and recompilations that compiles as will benefit from the missing index group, c.user_ The number of possible uses of lookups after indexing, c.user_ The number of scans that can be used after the index is created, c. Statement as table name, c.equality_columns, c.inequality_columns,c.included_columns, c. Name as library name, c.avg_ […]

  • Top 40 common operations of Python string


    The first official account is CoderMrWu. We share high-quality technology articles and experiences every week. Welcome everyone to pay attention to and share with you. Today, I read an article and summarized the common syntax of 40 Python string types. I feel it is very interesting. I’d like to share it with you. Although you […]

  • Cocos2d-x gets the getdpi () method of device class in Lua environment


    When doing multi-resolution adaptation, I encountered a special requirement. I need to do some adaptation work according to the real size in the real world. This requires calling the getdpi () method of the device class to obtain the DPI value of the current device screen. Unfortunately, cocos2d-x 3.2 does not export the device class […]

  • The Alibaba cloud toolkit creates an image and pushes it to the alicloud image warehouse


    Book connectionDocker package Maven project and push it to alicloud image warehouse Today, record the steps of creating an image with the Alibaba cloud toolkit and pushing it to the alicloud image warehouse maven setting.xml Write Alibaba cloud image warehouse information Create the namespace and image repository ahead of time IntelliJ idea settings – set […]

  • Mysql to determine whether there is another string in a string


      MySQL has many methods to determine whether there is another string in a string. For example, the more commonly used like and in are not introduced here. Today, we mainly introduce find_ In_ Use of set() and locate(). 1、 Find_ In_ set(str, strlist) find_ In_ Strlist() must be separated by a comma, otherwise the […]

  • Python learning – tuples


    Tuples are similar to lists, but the biggest difference is that tuples cannot be modified. List creation uses [, tuple creation uses () Tuples are also accessed through subscripts, such as:Create a tuple1 with elements of 1,2,3,4. When we access 3, we use tuple1 [2] as the subscript. Tuples can also be sliced like lists. […]