一开始是报了如下错误：
[ERROR] Failed to execute goal org.mybatis.generator:mybatis-generator-maven-plugin:1.3.2:generate (default-cli)
on project mmall: Execution default-cli of goal org.mybatis.generator:mybatis-generator-maven-plugin:1.3.2:generate
failed: Plugin org.mybatis.generator:mybatis-generator-maven-plugin:1.3.2 or one of
its dependencies could not be resolved: The repository system is offline but the artifact
org.codehaus.plexus:plexus-utils:jar:1.1 is not available in the local repository.
手动添加org.codehaus.plexus:plexus-utils:jar:1.1到仓库后。
执行mybatis-generator后，又报了如下错误：
[ERROR] Failed to execute goal org.mybatis.generator:mybatis-generator-maven-plugin:1.3.2:
generate (default-cli) on project mmall: Execution default-cli of goal org.mybatis.generator:
mybatis-generator-maven-plugin:1.3.2:generate failed: A required class was missing
while executing org.mybatis.generator:mybatis-generator-maven-plugin:1.3.2:generate:
org/mybatis/generator/exception/InvalidConfigurationException
找了许多方法，都不行，特来提问