maven pom.xml配置

		<!-- mybatis**** -->
        <dependency>
            <groupId>org.mybatis.generator</groupId>
            <artifactId>mybatis-generator-core</artifactId>
            <version>1.3.2</version>
        </dependency>
        <!-- c3p0连接池 -->
        <dependency>
            <groupId>com.mchange</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.2</version>
        </dependency>
        <!-- 连接mysql数据库 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.8</version>
        </dependency>

        <!-- mybatis核心包 -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.2.6</version>
        </dependency>

		<plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.2</version>
                <dependencies>
                    <dependency>
                        <groupId>mysql</groupId>
                        <artifactId>mysql-connector-java</artifactId>
                        <version>5.1.8</version>
                    </dependency>
                </dependencies>
                <configuration>
                    <!--配置文件的路径-->
                    <configurationFile>${basedir}/src/main/resources/generatorConfig.xml</configurationFile>
                    <overwrite>true</overwrite>
                </configuration>
        </plugin>

generatorConfig.xml 配置(上面插件配置中有指定配置文件路径)

<?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>

    <!--targetRuntime="MyBatis3" 目标环境
       MyBatis3：豪华版，复杂多条件查询
       MyBatis3Simple：helloWorld -->
    <context id="tables" targetRuntime="MyBatis3" defaultModelType="flat">
        <commentGenerator>
            <!-- 是否去除自动生成的注释 true:是;false:否 -->
            <property name="suppressAllComments" value="true"/>
        </commentGenerator>

        <!--数据库连接的信息：驱动类、连接地址、用户名、密码 -->
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/qjr" userId="root"
                        password="123456">
        </jdbcConnection>

        <!--oracle配置-->
        <!--
            <jdbcConnection driverClass="oracle.jdbc.OracleDriver" connectionURL="jdbc:oracle:thin:@127.0.0.1:1521:yycg"
                userId="yycg"
                password="yycg">
            </jdbcConnection>
        -->


        <!-- 默认false，把JDBC DECIMAL 和 NUMERIC 类型解析为 Integer，为 true时把JDBC DECIMAL
           和 NUMERIC 类型解析为java.math.BigDecimal -->
        <javaTypeResolver>
            <property name="forceBigDecimals" value="true"/>
        </javaTypeResolver>

        <!-- targetProject:生成Entity类的路径 -->
        <javaModelGenerator targetProject=".\src\main\java"
                            targetPackage="com.changye.mybatisplug.entity">
            <!-- enableSubPackages:是否让schema作为包的后缀 -->
            <property name="enableSubPackages" value="false"/>
            <!-- 从数据库返回的值被清理前后的空格 -->
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>

        <!-- targetProject:XxxMapper.xml映射文件生成的路径 -->
        <sqlMapGenerator targetProject=".\src\main\java"
                         targetPackage="com.changye.mybatisplug.mapper">
            <!-- enableSubPackages:是否让schema作为包的后缀 -->
            <property name="enableSubPackages" value="false"/>
        </sqlMapGenerator>

        <!-- targetPackage：Mapper接口生成的位置 -->
        <javaClientGenerator type="XMLMAPPER"
                             targetProject=".\src\main\java" targetPackage="com.changye.mybatisplug.mapper">
            <!-- enableSubPackages:是否让schema作为包的后缀 -->
            <property name="enableSubPackages" value="false"/>
        </javaClientGenerator>

        <!-- 数据库表名字和我们的entity类对应的映射指定 -->
        <table tableName="t_user"
               domainObjectName="User"

        />

    </context>
</generatorConfiguration>

运行插件

生成文件