mybatis基本用法

1、引入pom
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.1.3</version>
</dependency>

2、pom中开启驼峰命名转换
mybatis:
    configuration:
        map-underscore-to-camel-case: true

 3、编写数据库访问接口
@Repository
public interface XXXDao {
    @Select("<script>" +
            "SELECT * FROM t_xx where valid = 1 " +
            " <if test=\"des!= null and des !=''\"> and  des like CONCAT('%',#{des,jdbcType=VARCHAR},'%')</if>\n" +
            " order by id desc limit #{pageStart},#{pageSize}" +
            "</script>")
    List<ListXxVo> listXXX(XXInput input);

    //插入并获取自增长主键
    @Insert("INSERT INTO t_tree_node(parent_id,node_name,node_type) VALUES (#{parentId},#{nodeName},#{nodeType})")
    @Options(useGeneratedKeys=true,keyProperty="id",keyColumn = "id")
    long addNode(AddNodeReq input);

    @SelectProvider(type= XXSqlUtil.class, method = "countXXSql")
    int countXX(Input input);

    public String countXXSql(Input input){
        return "SELECT COUNT(1) FROM t_device_card where valid = 1";
    }
}

4、Application入口增加注解
@MapperScan("xxx.*.dao")
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}