除了自己写实体类，接口和映射之外，还可以使用 mybatis-generator-maven-plugin 来自动生成。

1. 添加 maven plugin 配置。

   <build>
    <plugins>
        <plugin>
            <groupId>org.mybatis.generator</groupId>
            <artifactId>mybatis-generator-maven-plugin</artifactId>
            <version>1.3.5</version>
            <dependencies>
                <dependency>
                    <groupId>org.mybatis.generator</groupId>
                    <artifactId>mybatis-generator-core</artifactId>
                    <version>1.3.5</version>
                </dependency>
                <dependency>
                    <groupId>mysql</groupId>
                    <artifactId>mysql-connector-java</artifactId>
                    <version>5.1.34</version>
                </dependency>
            </dependencies>
            <executions>
                <execution>
                    <id>mybatis-generator</id>
                    <phase>package</phase>
                    <goals>
                        <goal>generate</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <!-- 允许移动生成的文件 -->
                <verbose>true</verbose>
                <!-- 允许覆盖，生产环境应设置成false -->
                <overwrite>true</overwrite>
                <configurationFile>
                    src/main/resources/mybatis-generator.xml
                </configurationFile>
            </configuration>
        </plugin>
    </plugins>
   </build>
   

2. 修改 src/main/resources/mybatis-generator.xml 。

   <?xml version="1.0" encoding="UTF-8"?>
   <!DOCTYPE generatorConfiguration
        PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
   <generatorConfiguration>
    <context id="DB2Tables" targetRuntime="MyBatis3">
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/test"
                        userId="root"
                        password="123456">
        </jdbcConnection>
   
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>
        <!--实体类配置-->
        <javaModelGenerator targetPackage="generator.model" targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>
        <!--查询接口配置-->
        <sqlMapGenerator targetPackage="mapper" targetProject="src/main/java/generator">
            <property name="enableSubPackages" value="true"/>
        </sqlMapGenerator>
        <!--mapper映射配置-->
        <javaClientGenerator type="XMLMAPPER" targetPackage="generator.dao" targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
        </javaClientGenerator>
        <!--数据库表和实体映射配置-->
        <table schema="test" tableName="t_user" domainObjectName="User"
               enableCountByExample="true"
               enableUpdateByExample="true"
               enableDeleteByExample="true"
               enableSelectByExample="true"
               selectByExampleQueryId="true">
        </table>
    </context>
   </generatorConfiguration>
   

3. 运行插件。
   执行命令 mvn mybatis-generator:generate 即可在对应目录生成相应文件。