mysql-entity-generator

A small Java command-line tool that reads MySQL table metadata and generates a simple Java source skeleton:

• entity class
• mapper interface
• service interface
• service implementation

The project is intended for teams that want a lightweight starting point for CRUD-style Java modules without binding the generator itself to a specific web framework.

Features

• Reads column names, types, comments, length, scale, and nullable flags from MySQL metadata.
• Converts snake_case table and column names to Java class and field names.
• Maps common MySQL types to Java types such as String, Integer, Long, BigDecimal, LocalDate, and LocalDateTime.
• Generates plain Java classes with fields, comments, getters, and setters.
• Keeps generated mapper and service classes framework-neutral so they can be adapted to MyBatis, Spring, or another stack.

Requirements

• JDK 8 or later
• Maven 3.6 or later
• A reachable MySQL database

Build

mvn clean package

Usage

java -jar target/mysql-entity-generator-0.1.0.jar \
  --url=jdbc:mysql://localhost:3306/demo \
  --username=demo_user \
  --password=demo_password \
  --table=user_account \
  --package=com.example.generated \
  --output=generated-sources

Arguments:

Argument	Required	Description
--url	Yes	MySQL JDBC connection URL.
--username	Yes	Database username.
--password	Yes	Database password.
--table	Yes	Table name to generate from.
--package	No	Base Java package. Default is com.example.generated.
--output	No	Output directory. Default is generated-sources.

Generated files are written below the output directory using the selected base package:

generated-sources/
  com/example/generated/
    entity/UserAccount.java
    mapper/UserAccountMapper.java
    service/UserAccountService.java
    service/impl/UserAccountServiceImpl.java

Security Notes

Do not commit real database addresses, usernames, passwords, or private generated code. Use local environment variables or CI secrets when running the tool in automated jobs.

Roadmap

• Optional Lombok output mode.
• Optional MyBatis mapper XML generation.
• Config-file based execution.
• Unit tests for name conversion and type mapping.

License

MIT