What is the working principle and process of mybatis

Mybatis working principle and process: 1. Configuration file; 2. Interface and mapping; 3. SQL parsing and generation; 4. Execution plan; 5. Result processing; 6. Dynamic SQL; 7. Cache mechanism; 8. Plug-ins; 9. Transaction management; 10. Logging and monitoring; 11. Scalability. Detailed introduction: 1. Configuration file, MyBatis mainly relies on XML configuration file to define SQL statements, result mapping, transaction management and other information; 2. Interface and mapping, in MyBatis, the user needs to define an interface, and in the interface, etc. .

The operating system for this tutorial: Windows 10 system, DELL G3 computer.

MyBatis is an excellent persistence layer framework that supports customized SQL, stored procedures and advanced mapping. MyBatis can eliminate almost all JDBC code and manual setting of parameters and retrieval of result sets. MyBatis can use simple XML or annotations to configure and map native information, mapping interfaces and Java POJOs (Plain Old Java Objects, ordinary Java objects) into records in the database.

The working principle and process of MyBatis can be summarized as follows:

1. Configuration file: MyBatis mainly relies on XML configuration files to define SQL statements, result mapping, and transaction management and other information. Configuration files usually include , , and other elements, which are associated with Java objects through mapping relationships.

2. Interface and mapping: In MyBatis, the user needs to define an interface and declare the SQL method to be executed in the interface. Then, associate SQL statements with interface methods through XML configuration files or annotations. In this way, when the interface method is called, the corresponding SQL statement will be executed.

3. SQL parsing and generation: MyBatis parses SQL statements at runtime and generates corresponding execution plans based on the mapping relationships in the configuration file. This process involves multiple steps such as preprocessing, parameter binding, and result mapping.

4. Execution plan: After generating the execution plan, MyBatis will send the execution plan to the database for execution through JDBC. In this process, MyBatis will handle database connection, transaction management and other related work.

5. Result processing: After the database returns the results, MyBatis will convert the result set into a Java object according to the mapping relationship in the configuration file and return it to the caller.

6. Dynamic SQL: MyBatis supports dynamic SQL and can dynamically generate SQL statements based on the parameters passed in. For example, WHERE clauses can be spliced ​​together according to different conditions to implement complex query logic.

7. Caching mechanism: MyBatis has a built-in second-level cache mechanism, including first-level cache and second-level cache. The first-level cache is based on SqlSession, while the second-level cache is based on namespace. Query efficiency can be improved through the caching mechanism.

8. Plug-ins: MyBatis provides a plug-in mechanism. Users can customize plug-ins to implement specific functions, such as performance monitoring, interceptors, etc. Plug-ins can dynamically insert code while MyBatis is running, thereby extending its functionality.

9. Transaction management: MyBatis supports declarative transaction management, and transactions can be managed through simple annotations or XML configuration. In this way, developers can focus on the implementation of business logic without having to care about the specific details of transactions.

10. Logging and monitoring: MyBatis provides a log function that can record SQL statements, parameters, execution time and other information. These logs are very helpful for troubleshooting problems, monitoring system performance, etc.

11. Extensibility: MyBatis provides a wealth of extension points, and users can customize the implementation according to their needs. For example, components such as SQL parsers and result processors can be customized to meet specific needs.

In general, MyBatis simplifies the database access code through configuration files, interfaces and mappings, and improves performance and maintainability through precompilation, caching, plug-ins and other mechanisms. At the same time, MyBatis also provides a wealth of functions and extension points, allowing developers to customize their persistence layer framework according to specific needs.

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