1、在Maven的resources包文件夹下新建mybatis-config.xml,带数据库配置

<?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>
        <!--在控制台显示SQL语句-->
        <setting name="logImpl" value="STDOUT_LOGGING"/>
        <!--开启全局驼峰命名映射-->
<!--        <setting name="mapUnderscoreToCamelCase" value="true"/>-->
    </settings>
    
    <!--
    typeAliases给类名起别名
        typeAlias 给单个类配置别名,太麻烦了,每一个新增的类都得配置,不方便
            type:原本的包名+类名
            alias:起的别名
    -->
    <typeAliases>
<!--        <typeAlias type="com.itheima.pojo.User" alias="User"/>-->
<!--        <typeAlias type="com.itheima.pojo.Emp" alias="Emp"/>-->
        <package name="com.wsh.pojo"/>
    </typeAliases>
	
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <!--配置连接池需要的参数-->
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://192.144.23:3306/javatest?useSSL=false"/>
                <property name="username" value="root"/>
                <property name="password" value="wsh92"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
<!--        <mapper resource="UserMapper.xml"/>-->
<!--        <mapper resource="EmpMapper.xml"/>-->
        <package name="com.wsh.mapper"/>
    </mappers>
</configuration>

2、在Maven的resources包文件夹下新建和上面mapper一致的文件夹路径,编写UserMapper.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.wsh.mapper.UserMapper">
    <select id="getAll" resultType="com.wsh.pojo.User">
        select * from user
    </select>
    <select id="getUser" resultType="com.wsh.pojo.User">
        select * from user where id = #{id}
    </select>

</mapper>

#{变量名}:先使用?占位,后续将具体值赋给?

${变量名}:字符串拼接的形式,会存在 SQL 注入问题,尤其开起了 waf 防御的网站,会判定为病毒攻击从而拦截。小黄人_Minions-15