Code Generator

The brand-new MyBatis-Plus code generator allows you to quickly generate desired code through builder pattern, efficiently and elegantly. Follow the code below to see it in action.

FastAutoGenerator.create("url", "username", "password")
        .globalConfig(builder -> builder
                .author("Baomidou")
                .outputDir(Paths.get(System.getProperty("user.dir")) + "/src/main/java")
                .commentDate("yyyy-MM-dd")
        )
        .packageConfig(builder -> builder
                .parent("com.baomidou.mybatisplus")
                .entity("entity")
                .mapper("mapper")
                .service("service")
                .serviceImpl("service.impl")
                .xml("mapper.xml")
        )
        .strategyConfig(builder -> builder
                .entityBuilder()
                .enableLombok()
        )
        .templateEngine(new FreemarkerTemplateEngine())
        .execute();

Installation

Maven
Gradle

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-generator</artifactId>
    <version>3.5.14</version>
</dependency>

implementation 'com.baomidou:mybatis-plus-generator:3.5.14'

Since the code generator uses template engines, please manually include your preferred template engine. MyBatis-Plus Generator supports the following template engines:

VelocityTemplateEngine(Default)
FreemarkerTemplateEngine
BeetlTemplateEngine
EnjoyTemplateEngine

If you wish to use or adapt other template engines, you can extend AbstractTemplateEngine and implement custom solutions by referring to other template engine implementations.

Generation Methods

The code generator currently supports two generation methods:

DefaultQuery (Metadata Query)
- Advantages: Reads database metadata information through generic interfaces, offering better database compatibility.
- Disadvantages: Relies on database driver implementations.
- Note: Default method, some type handling may not be ideal.
SQLQuery (SQL Query)
- Advantages: Requires writing specific queries for tables, primary keys, and fields according to the database.
- Disadvantages: Poor compatibility, may face issues across different versions of the same database (e.g., H2 database only supports 1.X versions).
- Note: Will not be maintained in the future.

For known databases (without version compatibility issues), continue using the SQL query method as before. Example code:

// MYSQL example - Switching to SQL query method requires specifying dbQuery and typeConvert
FastAutoGenerator.create("url", "username", "password")
                .dataSourceConfig(builder ->
                        builder.databaseQueryClass(SQLQuery.class)
                                .typeConvert(new MySqlTypeConvert())
                                .dbQuery(new MySqlQuery())
                )
                // Other Config ...

Current issues with metadata query:

Does not support generating tables using NotLike approach.
Unable to read table comments. Solutions:
- Add remarks=true&useInformationSchema=true to MySQL connection properties.
- Add remarks=true or remarksReporting=true (for certain driver versions) to Oracle connection properties.
- SqlServer: Not supported by driver.
Poor handling of some PostgreSQL types (e.g., json, jsonb, uuid, xml, money). Solutions:
- Convert to custom types with custom TypeHandlers.
- Extend typeConvertHandler (typeName retrieval added in version 3.5.3.3).

MySQL tinyint field conversion issues:

When field length is 1, cannot convert to Boolean. Add &tinyInt1isBit=true to database connection.

When field length > 1, defaults to Byte. To convert to Integer, use:

FastAutoGenerator.create("url", "username", "password")
        .dataSourceConfig(builder ->
                builder.typeConvertHandler((globalConfig, typeRegistry, metaInfo) -> {
                    // Maintain backward compatibility with Integer conversion
                    if (JdbcType.TINYINT == metaInfo.getJdbcType()) {
                        return DbColumnType.INTEGER;
                    }
                    return typeRegistry.getColumnType(metaInfo);
                })
        );

Usage

You can use the code generator in the following two ways.

Quick Generation

Add generator code directly in the main method of CodeGenerator, configure accordingly, and run to generate code.

public static void main(String[] args) {
    FastAutoGenerator.create("url", "username", "password")
            .globalConfig(builder -> {
                builder.author("baomidou") // Set author
                        .enableSwagger() // Enable swagger mode
                        .outputDir("D://"); // Specify output directory
            })
            .dataSourceConfig(builder ->
                    builder.typeConvertHandler((globalConfig, typeRegistry, metaInfo) -> {
                        int typeCode = metaInfo.getJdbcType().TYPE_CODE;
                        if (typeCode == Types.SMALLINT) {
                            // Custom type conversion
                            return DbColumnType.INTEGER;
                        }
                        return typeRegistry.getColumnType(metaInfo);
                    })
            )
            .packageConfig(builder ->
                    builder.parent("com.baomidou.mybatisplus.samples.generator") // Set parent package
                            .moduleName("system") // Set parent module name
                            .pathInfo(Collections.singletonMap(OutputFile.xml, "D://")) // Set mapperXml output path
            )
            .strategyConfig(builder ->
                    builder.addInclude("t_simple") // Set tables to generate
                            .addTablePrefix("t_", "c_") // Set table prefix filters
            )
            .templateEngine(new FreemarkerTemplateEngine()) // Use Freemarker template engine (default is Velocity)
            .execute();
}

Interactive Generation

Interactive generation prompts for inputs during runtime. After completing configurations, it automatically generates the code.

public static void main(String[] args) {
    FastAutoGenerator.create("url", "username", "password")
            // Global config
            .globalConfig((scanner, builder) -> builder.author(scanner.apply("Enter author name?")))
            // Package config
            .packageConfig((scanner, builder) -> builder.parent(scanner.apply("Enter package name?")))
            // Strategy config
            .strategyConfig((scanner, builder) -> builder.addInclude(getTables(scanner.apply("Enter table names (comma-separated)? Enter 'all' for all tables")))
                    .entityBuilder()
                    .enableLombok()
                    .addTableFills(
                            new Column("create_time", FieldFill.INSERT)
                    )
                    .build())
            // Use Freemarker template engine (default is Velocity)
            .templateEngine(new FreemarkerTemplateEngine())
            .execute();
}

// Handle 'all' case
protected static List<String> getTables(String tables) {
    return "all".equals(tables) ? Collections.emptyList() : Arrays.asList(tables.split(","));
}

For more examples, check the test package samples:

Configuration

Refer to Code Generator Configuration.

Resources

👉 Source Code: Welcome to read and contribute.
👉 Video Tutorials: Welcome to follow, like, comment, and share.

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