【Exception in thread “main“ java.lang.NoClassDefFoundError: freemarker/template/Configuration】

问题

在引入mybatis-plus，使用代码生成器的过程中，遇到了如下问题：

17:42:52.444 [main] DEBUG com.baomidou.mybatisplus.generator.AutoGenerator - ==========================准备生成文件...==========================
Exception in thread "main" java.lang.NoClassDefFoundError: freemarker/template/Configuration
	at com.baomidou.mybatisplus.generator.engine.FreemarkerTemplateEngine.init(FreemarkerTemplateEngine.java:42)
	at com.baomidou.mybatisplus.generator.engine.FreemarkerTemplateEngine.init(FreemarkerTemplateEngine.java:37)
	at com.baomidou.mybatisplus.generator.AutoGenerator.execute(AutoGenerator.java:185)
	at com.baomidou.mybatisplus.generator.FastAutoGenerator.execute(FastAutoGenerator.java:239)
	at com.gpyj.data.MybatisPlusGenerator.main(MybatisPlusGenerator.java:47)
Caused by: java.lang.ClassNotFoundException: freemarker.template.Configuration
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	... 5 more

原因

MyBatis-Plus 从 3.0.3 之后移除了代码生成器与模板引擎的默认依赖，需要手动添加相关依赖

        <!--mybatis-plus-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.5.10.1</version>
        </dependency>

        <!--mybatis-plus代码生成-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-generator</artifactId>
            <version>3.5.10.1</version>
        </dependency>

		<!--模板引擎-->
        <dependency>
            <groupId>org.freemarker</groupId>
            <artifactId>freemarker</artifactId>
            <version>2.3.32</version>
        </dependency>