Understanding MyBatis Plugins: Use Cases, Mechanism, and Development Guide

MyBatis plugins, often referred to as interceptors, allow developers to intercept core MyBatis components (Executor, ParameterHandler, ResultSetHandler, StatementHandler) to implement features such as pagination, automatic field assignment, and performance monitoring.

Typical scenarios include converting in‑memory pagination to SQL‑level pagination, uniformly setting creator/modifier fields, and logging execution time of SQL statements.

The interceptor can target methods of the four core interfaces, and the plugin configuration is loaded from XML, where each interceptor class is instantiated, its properties are set, and it is added to the InterceptorChain.

MyBatis creates proxy objects for the target components using JDK dynamic proxies; the InterceptorChain’s pluginAll method wraps the target with each interceptor, forming a chain of proxies.

When a proxied method is invoked, the Plugin class’s invoke method checks whether the method matches the interceptor’s signature, executes the custom intercept logic if needed, and finally calls invocation.proceed() to continue the chain.

A concrete example shows how to implement a pagination plugin by extracting the original SQL and pagination parameters from the StatementHandler, rewriting the SQL, and proceeding with execution.

The article concludes that mastering MyBatis plugins requires understanding the four core interfaces, the dynamic‑proxy mechanism, and the design patterns involved (Proxy and Chain of Responsibility), while also noting performance considerations when stacking multiple plugins.