• 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 […]

  • Structure and algorithm (02): queue and stack structure


    Source code:GitHub. Click here || Gitee. Click here 1、 Queue structure 1. Basic concepts Queue is a kind of special linear table. Its particularity is that it only allows deletion at the front of the table, but inserts at the back end of the table. Like stack, queue is a kind of linear table with […]

  • Use of stack view in auto layout


    This is the second article on automatic layout.Use of < < auto layout LastThis article introduces how to use auto layout. This article mainly introducesStack view。Stack ViewProvides an easy way to use auto layout without introducing complex constraints. A single stack view defines the row or column of the user interface, and the stack view […]

  • The basics of the stack


    Stack What is a stack Stack operation Implement a stack class Application of stack Stack property privatization What is a stack A stack is a list of elements that can only be accessed from one end of the list (called the top). A common, real-life example is a tray stack in a cafeteria. Pallets are […]

  • Have you ever used mongodb? Have you stepped on these three pits?


    1: Background 1. Tell a story Some time ago, a friend asked in the wechat group why the time of inserting into mongodb was 8 hours less. 8 is a very sensitive number in time processing, and Geely is also a universal topic. Later, I think that friends who use mongodb for the first time […]

  • 07 CSS3 layout – Part 2 (front end must master)


    Abstract: in this article, you will see the common layout in CSS and some points you don’t pay attention to. Perfect for beginners! The ROC rises with the wind one day and soars to 90000 Li! Study together and make progress together! 1. Floatingfloat The code is as follows: <div class=”float-div”>Float</div> <p>It’s brave new world […]

  • How to help enterprise app occupy the first opportunity in the competition?


    Do a good job in the six words of product truth: just need, pain point, high frequency ——Zhou Hongyi Good products need constant polishing. Before the development of any product, we need to carry out strict assumptions and research to find the hard needs and find the pain points. Then it is to constantly verify […]

  • Interpretation of gulp plug-in – gulp util


    Knowledge preparation First of all, what is chalk chalk [ https://github.com/chalk/chalk ]Is a terminal string color display Talk usage install $ npm install chalk Common usage Basic Usage const chalk = require(‘chalk’) console.log(chalk.blue(‘Hello world!’)); Normal string combination log(chalk.blue(‘Hello’) + ‘ World’ + chalk.red(‘!’)); call chaining log(chalk.blue.bgRed.bold(‘Hello world!’)); Bird’s nest style log(chalk.red(‘Hello’, chalk.underline.bgBlue(‘world’) + ‘!’)); Multi […]

  • Don’t treat exceptions as business logic, which you can’t afford


    1: Background 1. Tell a story After years of hard work in the project, I should have seen more or less people treat exceptions as business logic (┬┬), such as judging whether a number is an integer, you can take it for grantedtry catch Wrap it up. Wrap it upint.ParseIf you throw an exception, it […]

  • JMM Java Memory Model


    JMM JMM:Java memory modelJMMThe abstract relationship between thread working memory and main memory is defined: shared variables between threads are stored in main memory, and each thread has a private local memory. In multithreading environment, JMM (JAVA memory model) has to be mentioned for the communication between threadsThe Java Memory Model (JMM) used within the […]

  • Restart Dafa! Online troubleshooting manual


    Introduction:This paper starts from the online practical problems and troubleshooting, sharing how to quickly locate and restore online common problems and faults, and summarizes a lot of practical methods, hoping to be useful to you. Location of common problems on the first line FAQ 1: high CPU utilization CPU utilization is an important indicator to […]

  • Performance optimization brochure – asynchronous stack trace: why await outperforms promise


    And direct usePromiseCompared withasync/awaitNot only can you make the code more readable, but you can also implement some interesting optimizations in the JavaScript engine. This article is about one of these optimizations involving stack tracing of asynchronous code. async/awaitandPromiseThe fundamental difference is thatawait fn()Pauses the execution of the current function, andpromise.then(fn)In the futurefnAfter the call […]