一、前言

Mybatis支持插件实现接口 org.apache.ibatis.plugin.Interceptor 来达到插件的功能，最常见的插件就是分页插件。
引入插件 pagehelper

<dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper</artifactId>
            <version>5.1.2</version>
</dependency>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <settings>
        <setting name="logImpl" value="STDOUT_LOGGING" />
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    </settings>
    <!--配置PageHelper分页插件拦截器-->
    <plugins>
        <plugin interceptor="com.github.pagehelper.PageInterceptor">
            <property name="offsetAsPageNum" value="true"/>
            <property name="helperDialect" value="mysql"/>
            <property name="rowBoundsWithCount" value="true"/>
            <property name="reasonable" value="true"/>
        </plugin>
    </plugins>
    <environments default="mysql">
        <environment id="mysql">
<!--            配置事务-->
            <transactionManager type="JDBC"></transactionManager>
<!--            配置连接池-->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/smiler_user?useUnicode=true&amp;characterEncoding=utf8"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
<!--    配置映射文件的位置-->
    <mappers>
<!--        <mapper resource="user/mapper/UserMapper.xml"></mapper>-->
<!--        用于指定dao接口所在的包，指定之后就不再需要写，mapper resources class  mapper.xml-->
        <package name="user.mapper"/>
    </mappers>
</configuration>

public static void main(String[] args) throws IOException {
        InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory factory = builder.build(in);
        SqlSession session = factory.openSession();
        //获得dao 的代理对象
        PageHelper.startPage(0,2);
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> user = userMapper.queryByName("king");
        PageHelper.clearPage();
//        User user2 = userMapper.queryById(21);
        System.out.println(user.toString());
//        userMapper.deleteById("1");
//        userMapper.deleteByName("'dasd' or 1=1");
        session.commit();
    }