Category:Informal Essay

  • Introduction to Python: 17 processes, threads and coroutines

    Time:2022-5-17

    process   To enable Python programs to implement multiprocessing, we first understand the relevant knowledge of the operating system. The UNIX / Linux operating system provides afork()System call, which is very special. Ordinary function call, call once, return once, butfork()Call once and return twice, because the operating system automatically copies the current process (called the […]

  • Three kinds of initialization and memory analysis

    Time:2022-5-17

    Three kinds of initialization and memory analysis Memory analysis Defines an array, which will push something into the stack; Once new creates an array, it opens up a space in the heap Initialization of array The first is to define and assign values directly int[] a={1,2,3,4,5}; The second method is to new an array, and […]

  • Controller cannot jump to static HTML under template

    Time:2022-5-17

    org.springframework.boot spring-boot-starter-thymeleaf  

  • Execution process of database SQL statement

    Time:2022-5-17

    1.   Connector: TCP protocol Connecting and disconnecting Verify authority, user name and password Number of connections: show processlist; kill  show global variables like ‘wait _ timeout’; Default sleep time: 8 hours After the connection, the user information is cached, and the permissions of the database are changed. The connection takes effect only after re […]

  • Gson parsing: Java Lang. illegalargumentexception: resolving the problems of declare multiple JSON fields named status

    Time:2022-5-16

    In the case of writing and defining the unified return value of the system at one time, I encountered Java Lang. illegalargumentexception: declare multiple JSON fields named status. Online Baidu has many solutions\ The specific methods are as follows: 1. Add transient before the field of duplicate name of parent class. However, you will find […]

  • [protobuf] [Java] compilation

    Time:2022-5-16

    1、 New proto file Create a new mytest Proto file syntax = “proto3”; package cc.protobuf; option java_package = “cc.protobuf.model”; option java_multiple_files = true; option java_outer_classname = “AddressBookProtos”; message Person { string name = 1; int32 id = 2; string emial = 3; } 2、 Compiling proto files CMD command: protoc –proto_path=E:\Code\WF\src\main\java\protobuf\ –java_out=E:\Code\WF\src\main\java\protobuf\ mytest.proto     […]

  • IOS certificate related

    Time:2022-5-16

    First, the IOS development certificate is that developer, distribution and MAC each have a root certificate. All real machine test certificates issued are matched under the corresponding certificates. All certificates of each corresponding app on the shelf cannot be removed or revoked, which will lead to the unavailability of online applications. And the different distribution […]

  • Configure pycharm proxy

    Time:2022-5-16

    If v2rayn is started locally, the default port is 10808, socks agent, and host is 127.0.0.1

  • HTML notes (Part I)

    Time:2022-5-16

    Document type declaration label : Document type declaration is used to tell the browser which HTML version to use to display web pages Lang language type The language used to define the current document display 1. En defines the language as English 2. Zh cn is defined in Chinese Character set Character set is a […]

  • Element cascade selector selection to get the complete array

    Time:2022-5-16

    The change method of element component only obtains the selected ID by default. If we want to obtain the selected name or other data at the same time, we can’t At this time, the component itself provides us with methods Here’s how to use it HTML script Obtain data according to different requirements. Here, I […]

  • vue3. 0 layput layout, hidden class based on breakpoints

    Time:2022-5-15

    Class name: Hidden XS only – hidden when viewport is at XS size Hidden SM only – hidden when the viewport is at SM size Hidden SM and down – hidden when the viewport is SM and below Hidden SM and up – hidden when the viewport is SM and above Hidden MD only – […]

  • The meaning of batch bat file under windows and shell file under Linux

    Time:2022-5-15

    Original text: https://www.cnblogs.com/caiguodong/p/10308255.html shell(Linux、Solaris) bat(windows) meaning # rem Comment line /【directory】/【directory】/…/【directory】/ 【disk】:\【directory】\【directory】\…\【directory】\ path [variable] = [file name], lbsam Set [variable] = [file name], BSAM Assign file name to variable [variable] = [set value] [variable] = “[set value]” [variable] = ‘[set value]’ [variable] = [set value]; Export [variable] Export [variable] = [set value] Set [variable] = […]