星海日和

This article introduces the Shoka theme's rich extended functions on Markdown syntax, covering GitHub Flavoured Markdown basic syntax, Mermaid charts, Infographic infographics, code highlighting, text effects, reminders and folding blocks, tab cards, friend chains and media players, exercise system, mathematical formula rendering and content encryption, etc., supports dark/light theme adaptation, and various functions can be independently switched on and off through configuration files. Comprehensively improve the readability, interactivity and expressiveness of Markdown content.

This article introduces in detail the process of building a front-end development environment, focusing on the use of Node.js and its package manager npm, as well as the method of managing multiple versions of Node.js through NVM for Windows on the Windows platform. The article guides users on how to correctly install and switch Node.js versions, clean up old environments, install project dependencies and start front-end development servers, and provides troubleshooting solutions for common problems to ensure the stability and consistency of the development environment.

This article systematically introduces Java exception handling mechanisms, including exception system classification (Error and Exception, which is further divided into runtime exceptions and checked exceptions), usage scenarios and specifications of try-catch-finally and try-with-resources, the difference between throws and throw, implementation of custom exceptions, and best practices for exception handling. It is emphasized that exceptions should be used in truly recoverable situations, to avoid blindly capturing and concealing errors, and to retain root cause information and provide clear error warnings to the outside world.

This article introduces date-time related APIs in Java, which are divided into two categories: old versions (Date, Calendar, SimpleDateFormat) and new versions (java.time package). Although the old version of the API can still be used for historical code maintenance, it has problems such as variability, thread insecurity and error-prone. It is recommended to use the immutable and thread-safe java.time API for new projects. The new Java 8 API provides clearer and more secure date-time classes, such as LocalDate, LocalDateTime, and DateTimeFormatter, which support precise date calculation and formatting and are recommended to be used first in new projects.

This article introduces in detail the three-way handshake and four-way waving mechanism in TCP protocol. The three-way handshake is used to establish a connection, which ensures that the connection is reliably established by synchronizing the initial serial numbers of both parties and confirming the communication capabilities; the four-way handshake is used to close the connection. Since TCP is a full-duplex protocol, transmission in both directions needs to be turned off respectively to ensure that the data is sent completely and reliably released. The process involves the use of serial numbers, acknowledgement numbers, flag bits (SYN, ACK, FIN), as well as the role of TIME-WAIT status to ensure the reliability of connection closure and the stability of the network environment.

This article details the use of EXPLAIN query plans in MySQL and the meaning of key fields. Using EXPLAIN, you can view the execution plan of SQL statements, including information such as access order, index selection, number of rows scanned, and whether sorting or temporary tables are needed to help analyze query performance. The article focuses on explaining the meaning of columns such as id, select_type, type, possible_keys, key_len, rows, filtered and Extra, and provides systematic ideas for analyzing execution plans. It is recommended to combine EXPLAIN ANALYZE to obtain actual execution data to verify the optimization effect.

This article demonstrates the implementation of commodity and category paging association query based on Spring Boot, MyBatis-Plus, MySQL, and Druid. The basic code was generated through reverse engineering, the paging plug-in was configured and the associated query between the commodity table and the category table was realized. Finally, the correctness of the paging function and associated fields was verified through testing, and common problems such as SQL mapping errors, paging ineffectiveness, and field ambiguity were pointed out. solution.

The article introduces the entire process of integrating Knife4j in the Spring Boot 3 project, emphasizing that Knife4j is an interface document enhancement tool based on the OpenAPI 3 specification. It generates documents through the springdoc-openapi and provides visual display and online debugging functions in conjunction with Swagger UI. It focuses on environment configuration, annotation use, security control, document export and troubleshooting of common problems. It points out that the Jakarta version of Knife4j Starter should be used correctly, scan packages and groups should be reasonably configured, and interface document access should be opened or restricted in the development and production environments respectively., clearly distinguish between interface concealment and privilege protection to ensure document security and functional integrity.

This article systematically introduces the core mechanisms and practical points of Spring transaction management. It focuses on the PlatformTransactionManager interface and its use in scenarios such as JDBC, JPA, Hibernate, and JTA, and explains in detail the meaning and configuration of transaction attributes (such as propagation behavior, isolation level, read-only flag, timeout time), as well as the management method of transaction state. At the same time, it compares the implementation methods of programmatic and declarative transactions, points out common failure scenarios and optimization suggestions of declarative transactions in practical applications, and emphasizes that transactions should be reasonably configured, avoid overuse, and ensure data consistency and system performance.

This article describes in detail the core execution process and key component responsibilities of Spring MVC, including front-end controller DispatcherServlet, processor mapping, parameter binding, view skipping, static resource processing and other mechanisms. It focuses on practical development scenarios such as request mapping, parameter binding, JSON data interaction, cross-domain processing, and file uploading, and emphasizes front-end separation, security and best practices, such as using annotations, reasonably configuring CORS, and avoiding direct exposure. File upload path, etc.