mybatis-spring-boot-starter配置以及使用

What is mybatis

MyBatis is a first class persistence framework with support for custom SQL, stored procedures and advanced mappings. MyBatis eliminates almost all of the JDBC code and manual setting of parameters and retrieval of results. MyBatis can use simple XML or Annotations for configuration and map primitives, Map interfaces and Java POJOs (Plain Old Java Objects) to database records.

Mybatis是一个支持自定义SQL，存储过程，高级映射的持久化框架。Mybatis几乎消除了所有的JDBC代码和Parameters的设置以及Results结果集的检索。Mybatis可以用XML文件或者注解来映射和配置。映射接口和JAVA POJOs到数据库记录。

优势

1. 支持自定义灵活SQL
2. 减少了大量JDBC操作，不需要手动开关连接
3. 数据库兼容性好
4. 提供映射标签，支持对象与数据库ORM字段关系映射；提供对象关系映射标签，支持对象关系组件维护

添加mybatis依赖

  <dependency>
      <groupId>org.mybatis.spring.boot</groupId>
      <artifactId>mybatis-spring-boot-starter</artifactId>
      <version>1.3.0</version>
  </dependency>

配置

1. 在application.properties配置mapper.xml的地址

mybatis.mapper-locations=classpath:mybatis/*.xml
type-aliases-package: com.gaolei.cn.dao

2. 在resources路径下创建mybatis文件夹，并且创建xxx.xml文件，添加如下配置

<?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.gaolei.cn.dao.GradeMapper">
    <insert id="insert" parameterType="com.gaolei.cn.entities.Grade">
        insert into grade(id,stu_num,score) values(#{id},#{stu_num},#{score})
    </insert>
</mapper>

Tips:namespace必须要映射到某个接口或者POJO的全路径

写Mapper接口

@Mapper
public interface GradeMapper {
    List<Grade> getAll();
}

调用

@Resource
private GradeMapper gradeMapper;
List<Grade> gradeList = gradeMapper.getAll();