（四）mybatis逆向工程

逆向工程就是说通过数据库当中的表生成class,mapper,接口，不需要自己编写那些，很方便。跟symfony里面的自动生成是一样的；视频里的人说用的不多，但我觉得很方便呀

具体步骤，首先导入MyBatis-generator-core.jar，

之后复制一下generator.xml文件：里面有注释，很容易看懂

<?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>
    <!--数据库驱动-->
    <!--
        如果IDE(eclipse或者idea) 项目里导入了jar包，那么就不需要配置了jar包的绝对路径了
         <classPathEntry    location="e:/project/mybatis/lib/mysql-connector-java-5.0.8-bin.jar"/>
    -->
    <context id="DB2Tables"    targetRuntime="MyBatis3">
        <commentGenerator>
            <property name="suppressDate" value="true"/>
            <property name="suppressAllComments" value="false"/>
        </commentGenerator>
        <!--数据库链接地址账号密码-->
        <jdbcConnection userId="root" driverClass="com.mysql.cj.jdbc.Driver" connectionURL="jdbc:mysql://localhost:3306/mybatis_generator?useUnicode=true&amp;characterEncoding=utf-8&amp;serverTimezone=GMT" password="wen52010">
        </jdbcConnection>
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>
        <!--生成Model类存放位置-->
        <javaModelGenerator targetPackage="Entity" targetProject="src">
<!--            <property name="enableSubPackages" value="true"/>-->
<!--            <property name="trimStrings" value="true"/>-->
        </javaModelGenerator>
        <!--生成映射文件存放位置-->
        <sqlMapGenerator targetPackage="Mapper" targetProject="src">
<!--            <property name="enableSubPackages" value="true"/>-->
        </sqlMapGenerator>
        <!--生成Dao类存放位置-->

        <javaClientGenerator type="XMLMAPPER" targetPackage="Mapper" targetProject="src">
            <property name="enableSubPackages" value="true"/>
        </javaClientGenerator>
        <table tableName="Student"></table>
        <table tableName="Adress"></table>
        <!--生成对应表及类名-->
<!--        <table tableName="category_" domainObjectName="Category" enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="true" selectByExampleQueryId="false">-->
<!--            <property name="my.isgen.usekeys" value="true"/>-->
<!--            <generatedKey column="id" sqlStatement="JDBC"/>-->
<!--        </table>-->
        <!--         <table tableName="product_" domainObjectName="Product" enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false"></table> -->
    </context>
</generatorConfiguration>

将路径名，表明等更改正确，

main函数之中，复制以下代码，运行就Ok,

        File file = new File("src/generator.xml");

        List<String> warnings = new ArrayList<String>();
        ConfigurationParser cp = new ConfigurationParser(warnings);
        Configuration config = cp.parseConfiguration(file);
        DefaultShellCallback callback = new DefaultShellCallback(true);
        MyBatisGenerator generator = new MyBatisGenerator(config,callback,warnings);
        generator.generate(null);