Because it is difficult to query every time you connect to the database, you occasionally need to convert the query results to a JSON file.
So temporarily define a MySQL class that encapsulates these commonly used methods for direct invocation (code is as follows, for personal use, without any comments).
Note: the package of https://github.com/stleary/JSON-java is imported.
1 package connmysql;
2
3 import java.io.IOException;
4 import java.io.InputStream;
5 import java.sql.Connection;
6 import java.sql.DriverManager;
7 import java.sql.PreparedStatement;
8 import java.sql.Res...
ACID（Atomicity Atomicity, Consistency consistency, Isolation isolation, Durability persistence) are a series of attributes.
These attributes ensure the reliability of database objects. In a database, a series of operations on data can be logically viewed as a whole operation, which is called things.
Atomicity” (atomicity)
Atomicity requires that all operations in each thing be either complete or as if none of them happened: if some of the operations in the thing fail, the whole thing fails, and the result is that the state in the database remains unchanged. Atomicity systems must ensu...
udevadm Then a command and command specify the options. It controls the behavior of udev, handles kernel events, controls event queues, and provides a simple debugging mechanism.
Options:
–debug Print error message
–version Print version information
–help Help document
udevadm info options Query the device information in the udev database. You can also query the properties of the device from the sysfs file system to help create the udev rules.
–query=type Query the specified type of device from the database. –path and –name are required...
Reference: traders using Python
【Preface: Starting with this tutorial, all development will take place in a Python environment (thank goodbye to C++).
Introduction of the underlying interface
1、Usually, the structure of a trading process consists of the following three parts:
The underlying interface: responsible for docking quotations and trading APIs, pushing data to the system core, and sending instructions (order, data request, etc.)
Middle-level engine: Used to integrate components (including underlying interfaces, database interfaces, etc.) into an object for top-level UI calls
Top...
Read a lot of posts, and finally find a suitable way in chaos.Self perception is relatively simple.Install the local GIT and download it at the official download address: http://git-scm.com/download/download the corresponding version on your own system.Administrator@USER-20170816VX MINGW64 /g/project/10guang （The file to be submitted on the desktop, right-click to select git bash here.$git clone https://github.com/gaobing1252/web-app.git (using warehouse addresses to generate web-appDirectory, which is inside the submission file, and then copies the contents of the file to the generated we...
HTMLDefinition
Hypertext Markup Language (HTML) is also a markup language to create web pages.
Essentially browser-recognizable rules, we write web pages according to rules, browsers render our web pages according to rules, for different browsers, the same tag may have different interpretations (compatibility issues)
Web file extension:.Html/.htm (the latter is not commonly used)
Hypertext: refers to the page can contain pictures, links, and even music, programs and other non text.
Markup Language: the language of tags (labels).
Web page ==HTML document, resolved by browser, used to display...
Fatal error: software package java.lang cannot be found in classpath or boot classpath.
Change the POM file
Windows（Separator semicolon);
<bootclasspath>${java.home}/lib/rt.jar;${java.home}/lib/jce.jar</bootclasspath>
linux(Separator colon English colon):
<bootclasspath>${java.home}/lib/rt.jar:${java.home}/lib/jce.jar</bootclasspath>
Special thanks: https://blog.csdn.net/skate6/article/details/70597104
1.If the data returns is this.
getProductList:[
{
productName:'Watermelon ',ProductPrice:100,PrductQty:1},{ProductName:'pumpkin',ProductPrice:50,PrductQty:2},{ProductName:'Apple',ProductPrice:300,PrductQty:3},]
2.If you want to determine if there is a checked field in the item, how do you judge and add it?
Overall situation
if(typeof item.checked=='undefined'){
Vue.set(item,"checked",true)//First determine whether this field does not exist, do not exist, add it, and add it globally.}else{Item.checked=! Item.checked / / here, according to actual needs.}
...
