Tag:Memory

  • VMware and CentOS system installation

    Time:2020-1-22

    Catalog 1. Download CentOS system ISO image 2. Install VMware virtual machine 3. Why learn Linux through VM virtual machine? 4. Teach you how to install virtual machine with hands 4.1 decompress the package. Vm12 is currently selected 4.2 install Linux after installing VMware virtual machine 4.3 completion of installation 5. Make sure your Linux […]

  • Some recent PHP tips

    Time:2020-1-21

    Original link: he Xiaodong blog A good framework can improve the language ecology, and sometimes make PHP programmers become framework programmers instead of better back-end programmers, such as me. The test environment is php7.4 windows 10 system STR replace function A small requirement is similar to filling in blanks with words, replacing words with several […]

  • Redis data structure (2) – string

    Time:2020-1-19

    Redis 5.0 based version. The encoding of string object is: int, raw or embstr. 1.raw Raw isredisObject+sdsThat is to sayredisObjectOfptrPointer to asdsObject. // object.c define OBJ_ENCODING_EMBSTR_SIZE_LIMIT 44 robj *createStringObject(const char *ptr, size_t len) { if (len <= OBJ_ENCODING_EMBSTR_SIZE_LIMIT) return createEmbeddedStringObject(ptr,len); else return createRawStringObject(ptr,len); } // rwa robj *createRawStringObject(const char *ptr, size_t len) { return createObject(OBJ_STRING, […]

  • Memory authentication based on spring boot integrating spring security (1)

    Time:2020-1-18

    Memory authentication based on spring boot integrating spring security (1) In the first tutorial, we have a brief understanding of spring security’s usage posture, add dependencies, and use theapplication.ymlAdd a few lines of configuration in the file to realize a basic login authentication; The default configuration can only set one account. How can multiple accounts […]

  • To implement Java local caching, start from these points

    Time:2020-1-18

    Cache, I believe you must be familiar with it, in the project, cache is absolutely necessary. There are many caching tools on the market, such as redis, guava cache or ehcache. I think you are very familiar with these tools, so today we don’t talk about them. Let’s talk about how to implement local caching. […]

  • Class loading problem caused by parallel flow in Tomcat application

    Time:2020-1-18

    This article starts with vivo Internet technology WeChat public.Link: https://mp.weixin.qq.com/s/f-x3n9cvdyu5f5nyh6mhxqAuthor: Xiao Mingxuan, Wang daohuan With the popularity of Java 8, more and more developers use parallel to improve code execution efficiency. However, the author found that the use of parallel flow in Tomcat container would lead to the failure of dynamic loading of classes. By […]

  • Why implement IDisposable interface?

    Time:2020-1-15

    Background Recently, I found a problem in the intensive reading of CLR via C Chen and effective c Chen. Generally speaking, we achieveIDisposableInterface to release managed and unmanaged resources. However, there is a similar function in the definition of C ා type, which isFinalization device。 At the beginning, I studied C + +. Later, when […]

  • Go basic programming practice (10) – Database

    Time:2020-1-15

    Read data from database Download SQLite3 visualizer at http://sqlitebrowser.org/ and create it in the same directory as main.gopersonal.dbDatabase, create the table as follows: package main import ( “database/sql” “fmt” _ “github.com/mattn/go-sqlite3” ) //Using struct type to map data from SQL database to objects in memory type Profile struct { ProfileId int FirstName string LastName string […]

  • For performance, PHP excel extension xlswriter 1.3.3 is released!

    Time:2020-1-14

    Xlswriter is a PHP C extension that can be used to read data in Excel 2007 + xlsx files, insert multiple worksheets, and write text, numbers, formulas, dates, charts, pictures, and hyperlinks. It has the following features: First, write 100% compatible excel xlsx file Complete excel format merge cell Define sheet name Filter Chart Data […]

  • Redis data structure (3) – linked list

    Time:2020-1-13

    Redis 5.0 based version. The character codes of redis list include ziplist and QuickList, and the old version also has linkedlis. 1. linkedlist 3.2LinkedList will no longer be used in the list after the release, but it is listed here for comparison. struct list { Listnode * head; // header node Listnode * tail; // […]

  • Seriously, I found a mistake in this book!

    Time:2020-1-13

    This article starts with the public number [why technology], pays attention to the public number, has a better typesetting way, and has a better reading experience. Hateful title party First of all, let me talk about the mistakes I found in the art of Java Concurrent Programming.The edition of the art of Java Concurrent Programming […]

  • MySQL optimization ideas

    Time:2020-1-13

    1、 Overall optimization ideas First, build a script to observe the number of queries, connections and other data, determine the environmental reasons and internal SQL execution reasons, and then do specific processing according to the specific reasons. 2、 Build script watch state mysqladmin -uroot -p ext \G   The command can obtain the current query […]