Write binary, gesture must be Sao, save fields, save bandwidth, increase efficiency...

introduce Last week, I was confronted with a colleague about an interface. My front-end colleague asked me if I had written the interface document incorrectly, how many exception tags are on an order, and should I not return an array?Why only one number was returned. Because this interface is a call to other micro services, I am also confused. ...

Posted by joeman3429 on Wed, 12 Feb 2020 18:05:04 -0800

mybatis - Execute getById

1. Execution of getById Previous As mentioned, when Mapper.java is created, it is created as a jdk proxy and the proxy processing class is MapperProxy. So when the getById method of UserMapper is executed, the invoke method is executed in MapperProxy. //MapperProxy.java @Override public Object invoke(Object proxy, Method method, Object[ ...

Posted by Darkwoods on Wed, 12 Feb 2020 10:28:46 -0800

Data normalization in Python: connection, union and reconstruction

This blog is a reading note of "data analysis by Python". Please do not reprint it for other business purposes. Article directory 1. Hierarchical index 1.1 reorder and hierarchy 1.2 summary statistics by level 2. Join and merge datasets 2.1 database style DataFrame connection 2.2 merge by ...

Posted by AustinP on Wed, 12 Feb 2020 04:56:09 -0800

mysql database technology 1 - Basic addition, deletion and alteration sql statements

1. Classification of database languages DDL: Database Definition Language Used to create, modify, and delete data structures within a database, such as: 1: Create and delete databases (CREATE DATABASE || DROP DATABASE); 2: Create, modify, rename, delete tables (CREATE TABLE | ALTER TABLE | RENAME TABLE | DROP TABLE, TRUNCATE TABLE); 3: Create a ...

Posted by timmerk on Tue, 11 Feb 2020 20:46:07 -0800

The book management system of Java practice (swing version) - other interfaces and function realization

Summary of this section This section mainly realizes the final function of the software and some summary of the project.   About the function of software The function of the software is to pop up a dialog box, tell the user some information about the software, and use the JDialog of swing to comp ...

Posted by opalelement on Tue, 11 Feb 2020 09:50:28 -0800

SpringBoot+Security dynamic configuration permission

Preface In today's web development, the authentication of security rights has always played an important role, so Spring has also produced its own security module, but this is a relatively heavy framework, configuration is quite cumbersome. Later, shiro, a lightweight security framework, emerged. The ...

Posted by spaze on Tue, 11 Feb 2020 05:32:51 -0800

MySQL transaction, permission, index and specification

One transaction Core: success or failureAtomicity Both succeed or fail Consistency The data integrity before and after the transaction should be consistent, 1000 Principle: ACID1. Atomicity Either they succeed or they fail; 2. Consistency Data integrity before and after transactions should be consiste ...

Posted by nawal on Tue, 11 Feb 2020 02:41:44 -0800

Using spring boot + mybatis + RabbitMQ + redis to simulate the second kill function of the mall

Using spring boot + mybatis + RabbitMQ + redis to simulate the second kill function of the mall First, we need to install RabbitMQ. Before installing RabbitMQ, we need to install Erlang, because RabbitMQ is based on Erlang. For specific steps, click the following link: After installation, RabbitMQ i ...

Posted by newjsguy on Tue, 11 Feb 2020 01:49:52 -0800

Data Structure Handwriting Tree Traversal (Full Implementation)

1. Summary of Previous Situation This is a tree traversal implementation. To focus on how queues are implemented, follow these articles:Data structure (3) Handwritten queues2. Basic concepts of trees Chain lists, stacks, and queues are one-to-one linear structures, one-to-many linear structures - trees. ...

Posted by amrigo on Mon, 10 Feb 2020 21:47:25 -0800

What does -e mean in mysql database?Detailed use of the -e parameter

Can be manipulated with shell scripts mysqldata base , mysql-e parameter can be used to perform various sql operations (create, delete, add, delete, change, check). usage The sql statement of mysql-hhostname-Pport-uusername-ppassword-e related MySQL allows you to manipulate mysql's methods in a shell without running MySQL at ...

Posted by n14charlie on Mon, 10 Feb 2020 08:26:27 -0800