Programmer Think

abnormal 1. Definition: Errors detected at runtime. 2. Phenomenon: When an exception occurs, the program will not execute down, but go to the call statement of the function. 3. Common exception types: – name error: the variable is undefined. – type error: operation with different types of data. – index error: out of inde ...

1. Introduction to mybatis 1.1 original jdbc operation (query data) 1.2 original jdbc operation (insert data) 1.3 analysis of original jdbc operation The problems existing in the original jdbc development are as follows: ① The frequent creation and release of database connections cause a waste of system resources, which affects the sys ...

catalogue 1. The exit state of the child process is not collected by the parent process and becomes a dead process (zombie process) 2. The exit status of the child process is collected by the parent process and the wait function is called 2.1: the status parameter of the wait function is null. 2.2: the status parameter of the wait function ...

1, Background es comes with a lot of word splitters, such as standard, whitespace, language (such as english), but they are not very good for Chinese word segmentation. A third-party word splitter ik is installed here to realize word segmentation. 2, Install ik word splitter 1. Find the word breaker matching this es version from github # Do ...

trigger 1. Define trigger CREATE TRIGGER Syntax format CREATE TRIGGER <Trigger Name > {BEFORE | AFTER} <Trigger event> ON <Table name> REFERENCING NEW|OLD ROW AS<variable> FOR EACH {ROW | STATEMENT} [WHEN <Trigger condition>]<Trigger action body> When a specific system e ...

Project introduction Federated learning algorithm is used to classify emnist data sets. First of all, we should clarify a knowledge point, which is the modifier @ TFF tf_ Calculation and @ TFF federated_ The difference between computation: tensorflow_ The federated (TFF) operation deals with federated values;Each Federation value has a f ...

1, Flume optimization 1. Adjust the memory size of Flume process, It is recommended to set 1G~2G. Too small will lead to frequent GC Because Flume process is also based on Java, it involves the memory setting of the process. Generally, it is recommended to set the memory of a single Flume process (or a single Agent) to 1G~2G. If the memory is ...

1 - Controller The complex controller provides the behavior of accessing the application program, which is usually realized by interface definition or annotation definition.The controller is responsible for parsing the user's request and transforming it into a model.In Spring MVC, a Controller class can contain multiple methods. In Spring MVC, ...

1. Concept A reptile is not an animal, but a computer program. This program has its own specific functions, which can browse the world wide web and obtain the required information according to a series of rules given by users. Such programs are called web crawler s or spider s. It has the ability of intelligent analysis, also known as robot p ...

Install rockrmq and rockrmq console in docker environment 1. Download the image of rocketmq docker pull apacherocketmq/rocketmq 2. Start NameServer docker run --name rmqnamesrv -p 9876:9876 \ -v /Users/liqi/docker-compose/rocketmq/data/namesrv/logs:/home/rocketmq/logs \ -d apacherocketmq/rocketmq sh mqnamesrv The above instructions a ...