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是一個支持自定義SQL，存儲過程，高級映射的持久化框架。Mybatis幾乎消除了所有的JDBC代碼和Parameters的設置以及Results結果集的檢索。Mybatis可以用XML文件或者註解來映射和配置。映射接口和JAVA POJOs到數據庫記錄。

優勢

1. 支持自定義靈活SQL
2. 減少了大量JDBC操作，不需要手動開關連接
3. 數據庫兼容性好
4. 提供映射標籤，支持對象與數據庫ORM字段關係映射；提供對象關係映射標籤，支持對象關係組件維護

添加mybatis依賴

  <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路徑下創建mybatis文件夾，並且創建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必須要映射到某個接口或者POJO的全路徑

寫Mapper接口

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

調用

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