引入Mybatis的starter依赖
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.1</version>
</dependency>
编写Entity
@Entity
@DynamicUpdate
@Data
public class ProductCategory {
/** 类目id. */
@Id
@GeneratedValue
private Integer categoryId;
/** 类目名字. */
private String categoryName;
/** 类目编号. */
private Integer categoryType;
private Date createTime;
private Date updateTime;
public ProductCategory() {
}
}
基于注解的方式
在接口上用注解编写SQL
public interface ProductCategoryMapper {
@Insert("insert into product_category(category_name, category_type) values (#{categoryName, jdbcType=VARCHAR}, #{category_type, jdbcType=INTEGER})")
int insertByMap(Map<String, Object> map);
@Insert("insert into product_category(category_name, category_type) values (#{categoryName, jdbcType=VARCHAR}, #{categoryType, jdbcType=INTEGER})")
int insertByObject(ProductCategory productCategory);
@Select("select * from product_category where category_type = #{categoryType}")
@Results({
@Result(column = "category_id", property = "categoryId"),
@Result(column = "category_name", property = "categoryName"),
@Result(column = "category_type", property = "categoryType")
})
ProductCategory findByCategoryType(Integer categoryType);
@Select("select * from product_category where category_name = #{categoryName}")
@Results({
@Result(column = "category_id", property = "categoryId"),
@Result(column = "category_name", property = "categoryName"),
@Result(column = "category_type", property = "categoryType")
})
List<ProductCategory> findByCategoryName(String categoryName);
@Update("update product_category set category_name = #{categoryName} where category_type = #{categoryType}")
int updateByCategoryType(@Param("categoryName") String categoryName,
@Param("categoryType") Integer categoryType);
@Update("update product_category set category_name = #{categoryName} where category_type = #{categoryType}")
int updateByObject(ProductCategory productCategory);
@Delete("delete from product_category where category_type = #{categoryType}")
int deleteByCategoryType(Integer categoryType);
ProductCategory selectByCategoryType(Integer categoryType);
}
基于xml方式
1.编写mapper接口
2.在resource目录下新建mapper包编写对应类的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.imooc.dataobject.mapper.ProductCategoryMapper" >
<resultMap id="BaseResultMap" type="com.imooc.dataobject.ProductCategory">
<id column="category_id" property="categoryId" jdbcType="INTEGER" />
<id column="category_name" property="categoryName" jdbcType="VARCHAR" />
<id column="category_type" property="categoryType" jdbcType="INTEGER" />
</resultMap>
<select id="selectByCategoryType" resultMap="BaseResultMap" parameterType="java.lang.Integer">
select category_id, category_name, category_type
from product_category
where category_type = #{category_type, jdbcType=INTEGER}
</select>
</mapper>
加入到spring容器
在SpringBoot程序入口加上@MapperScan注解扫描mapper接口所在路径
@SpringBootApplication
@MapperScan(basePackages = "com.imooc.dataobject.mapper")
@EnableCaching
public class SellApplication {
public static void main(String[] args) {
SpringApplication.run(SellApplication.class, args);
}
}
在application配置文件中加入xml文件所在路径(注解方式可省略)
mybatis:
mapper-locations: classpath:mapper/*.xml
总结-注意事项
1.使用注解方式时,如果入参个数大于两个必须使用@Param注解
@Update("update product_category set category_name = #{categoryName} where category_type = #{categoryType}")
int updateByCategoryType(@Param("categoryName") String categoryName,
@Param("categoryType") Integer categoryType);
2.当参数大于两个时,入参可以选择Map也可以选择Object,但注意sql写法要加上jdbcType
@Insert("insert into product_category(category_name, category_type) values (#{categoryName, jdbcType=VARCHAR}, #{category_type, jdbcType=INTEGER})")
int insertByMap(Map<String, Object> map);
@Insert("insert into product_category(category_name, category_type) values (#{categoryName, jdbcType=VARCHAR}, #{categoryType, jdbcType=INTEGER})")
int insertByObject(ProductCategory productCategory);
3.当使用查询方法时,返回多条数据,返回类型要使用集合类型,否则报错(JPA会返回第一条数据,Mybatis在这里相比更严禁)
@Select("select * from product_category where category_name = #{categoryName}")
@Results({
@Result(column = "category_id", property = "categoryId"),
@Result(column = "category_name", property = "categoryName"),
@Result(column = "category_type", property = "categoryType")
})
List<ProductCategory> findByCategoryName(String categoryName);
4.建议在开发环境在mapper层配置好sql的log
logging:
level:
com.imooc.dataobject.mapper: trace