mybatis-generator:generate 生成代码配置踩坑详解

mybatis-generator:generate 生成代码配置踩坑不少，在此留下笔记以便后续填坑
一、mysql返回时间问题
错误信息：

[ERROR] Failed to execute goal org.mybatis.generator:mybatis-generator-maven-plugin:1.3.2:generate (default-cli) on project coisini-mango-server: 
The server time zone value '???ú±ê×??±??' is unrecognized or represents more than one time zone.
You must configure either the server or JDBC driver (via the serverTimezone configuration property) 
to use a more specifc time zone value if you want to utilize time zone support. -> [Help 1]

JDBC需要配置服务器时区值， 在jdbc连接的url后面加上serverTimezone=GMT即可解决问题，如果使用GMT+8时区，需要写成GMT%2B8，如下：
1、application.properties的写法：

url: jdbc:mysql://localhost:3306/coisini?useUnicode=true&zeroDateTimeBehavior=convertToNull&autoReconnect=true&characterEncoding=utf-8&serverTimezone=GMT%2B8

2、generator.xml的写法，注：在xml中写&,会因为未转义而报错要将&写成&

<jdbcConnection driverClass="com.mysql.cj.jdbc.Driver" connectionURL="jdbc:mysql://127.0.0.1:3306/coisini?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf-8&useSSL=false" userId="root" password="sunday"></jdbcConnection>

二、找不到数据库连接驱动包
1、错误信息：

[ERROR] Failed to execute goal org.mybatis.generator:mybatis-generator-maven-plugin:1.3.2:generate (default-cli)
on project coisini-mango-server: Execution default-cli of goal org.mybatis.generator:mybatis-generator-maven-
plugin:1.3.2:generate failed: Exception getting JDBC Driver: com.mysql.cj.jdbc.Driver -> [Help 1]

关于这个异常，网上大多数说在generatorConfig.xml中加入数据库驱动包的绝对路径，
方法一：

<classPathEntry  location="G:\Program Files\java\apache-maven-3.6.1\repository\mysql\mysql-connector-java\8.0.13\mysql-connector-java-8.0.13.jar"/>

采用绝对路径后，编译会报一个弃用警告
警告信息：

Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. 
The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.

这里就引出了我们解决找不到数据库连接驱动包的办法，
方法二：
更改mysql驱动类为com.mysql.cj.jdbc.Driver，application.properties和generator.xml都要改
在pom.xml中plugin节点下添加mysql-connector-java的dependency

<plugin>
    <groupId>org.mybatis.generator</groupId>
     <artifactId>mybatis-generator-maven-plugin</artifactId>
     <version>1.3.2</version>
     <configuration>
         <configurationFile>src/main/resources/generator/generator.xml</configurationFile>
         <overwrite>true</overwrite>
         <verbose>true</verbose>
     </configuration>
 </plugin>

spring boot本就是通过maven自动配置，这里建议采用方法二，不建议使用配置绝对路径。
详细代码移步：mybatis 生成代码配置 mybatis-generator:generate 的使用详解