一、select
<select id="selectPerson" parameterType="int" resultType="hashmap"> SELECT * FROM PERSON WHERE ID = #{id} </select>
说明： #{id}告诉mybatis创建PreparedStatement参数 vs ORDER BY ${columnName}: 不转义
select支持的参数说明，具体参考 https://mybatis.org/mybatis-3/zh/sqlmap-xml.html
二、insert, update 和 delete
支持主键自动生成的配置
<insert id="insertAuthor" useGeneratedKeys="true" keyProperty="id"> insert into Author (username,password,email,bio) values (#{username},#{password},#{email},#{bio}) </insert> <update id="updateAuthor" parameterType="domain.blog.Author" flushCache="true" statementType="PREPARED" timeout="20"> <delete id="deleteAuthor" parameterType="domain.blog.Author" flushCache="true" statementType="PREPARED" timeout="20">
执行效果：
<mapper namespace="com.test.mapper.UserMapper"> <insert id="save" useGeneratedKeys="true" keyProperty="user_id"> insert into t_user (user_name, password, user_type, locked, credit, last_visit, last_ip) values ( #{user_name}, #{password}, #{user_type}, #{locked}, #{credit}, #{last_visit}, #{last_ip}) </insert>
</mapper>
测试代码
User user = User.builder().user_name("aaa").password("123456").user_type(1).credit(100).last_ip("11.11.11.11").build();
userMapper.save(user);
三、sql
定义可重用的 SQL 代码片段，以便在其它语句中使用
四、ResultMap
1）基本使用：
<!-- mybatis-config.xml 中，别名 --> <typeAlias type="com.someapp.model.User" alias="User"/> <!-- 解决列名不匹配 --> <resultMap id="userResultMap" type="User"> <id property="id" column="user_id" /> <result property="username" column="user_name"/> <result property="password" column="hashed_password"/> </resultMap> <select id="selectUsers" resultMap="userResultMap"> select user_id, user_name, hashed_password from some_table where id = #{id} </select>