import java.io.File;

 import java.io.IOException;

 import java.sql.SQLException;

 import java.util.ArrayList;

 import java.util.List;  

 import org.mybatis.generator.api.MyBatisGenerator;

 import org.mybatis.generator.config.Configuration;

 import org.mybatis.generator.config.xml.ConfigurationParser;

 import org.mybatis.generator.exception.InvalidConfigurationException;

 import org.mybatis.generator.exception.XMLParserException;

 import org.mybatis.generator.internal.DefaultShellCallback;  

 public class GenMain {

     public static void main(String[] args) {

         List<String> warnings = new ArrayList<String>();

         boolean overwrite = true;

         String genCfg = "generatorConfig.xml";

         File configFile = new File(GenMain.class.getResource(genCfg).getFile());

         ConfigurationParser cp = new ConfigurationParser(warnings);

         Configuration config = null;

         try {

             config = cp.parseConfiguration(configFile);

         } catch (IOException e) {

             e.printStackTrace();

         } catch (XMLParserException e) {

             e.printStackTrace();

         }

         DefaultShellCallback callback = new DefaultShellCallback(overwrite);

         MyBatisGenerator myBatisGenerator = null;

         try {

             myBatisGenerator = new MyBatisGenerator(config, callback, warnings);

         } catch (InvalidConfigurationException e) {

             e.printStackTrace();

         }

         try {

             myBatisGenerator.generate(null);

         } catch (SQLException e) {

             e.printStackTrace();

         } catch (IOException e) {

             e.printStackTrace();

         } catch (InterruptedException e) {

             e.printStackTrace();

         }

     }

 }  

 <?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="testTables" targetRuntime="MyBatis3">

         <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/mybatis"

             userId="root"

             password="123456">

         </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="false" />

         </javaTypeResolver>

         <!-- targetProject:生成PO类的位置 -->

         <javaModelGenerator targetPackage="com.itheima.mybatis.po"

             targetProject=".\src">

             <!-- 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:mapper映射文件生成的位置 -->

         <sqlMapGenerator targetPackage="com.itheima.mybatis.mapper"

             targetProject=".\src">

             <!-- 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"

             targetPackage="com.itheima.mybatis.mapper"

             targetProject=".\src">

             <!-- enableSubPackages:是否让schema作为包的后缀 -->

             <property name="enableSubPackages" value="false" />

         </javaClientGenerator>

         <!-- 指定数据库表 -->

         <table schema="" tableName="user"></table>

         <table schema="" tableName="orders"></table>

         <table schema="" tableName="orderdetail"></table>

         <table schema="" tableName="items"></table>

         <!-- 有些表的字段需要指定java类型

          <table schema="" tableName="">

             <columnOverride column="" javaType="" />

         </table> -->

     </context>

 </generatorConfiguration>