MyBatis-Spring-Boot 使用总结
mybatis开发团队为Spring Boot 提供了 MyBatis-Spring-Boot-Starter 。
首先,MyBatis-Spring-Boot-Starter will:
- Autodetect an existing DataSource.
- Will create and register an instance of a SqlSessionFactoryBean passing that DataSource as an input.
- Will create and register an instance of a SqlSessionTemplate got out of the SqlSessionFactoryBean.
- Autoscan your mappers, link them to the SqlSessionTemplate and register them to Spring context so they can be injected into your beans.
就是说,使用了该Starter之后,只需要定义一个DataSource即可,它会自动创建使用该DataSource的SqlSessionFactoryBean以及SqlSessionTemplate。会自动扫描你的Mappers,连接到SqlSessionTemplate,并注册到Spring上下文中。
MyBatis-Spring-Boot-Application的配置参数也是保存在application.properties文件中,使用前缀 mybatis 。
Property | Description |
---|---|
config-location | MyBatis xml config file (optional) |
mapper-locations | Mapper xml config files (optional) |
type-aliases-package | Package to search for type aliases (optional) |
type-handlers-package | Package to search for type aliases (optional) |
executor-type | Executor type: SIMPLE, REUSE, BATCH (optional) |
configuration | A MyBatis Configuration bean. About available properties see the MyBatis reference page. NOTE This property cannot use at the same time with the config-location. |
(Starter)设置mapper有两种方法:
①使用config-location指定一个config xml,在里面设置 mapper 和 alias 。见例子1。
②使用type-aliases-package,需要配合自动扫描Mappers使用。
针对第二种,需要注意的是,如果想要自动扫描Mappers,需要在Mapper接口上标注@Mapper,否则失败。另外,还需要在application.properties文件中声明:mybatis.type-aliases-package 。
mapper-locations这个配置参数仅当mapper xml与mapper class不在同一个目录下时有效。所以一般可以忽略。
例子1(通过 mybatis.config-location 指定config xml,然后在里面设置别名和mapper包):
#application.properties
mybatis.config-location=mybatis-config.xml
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <typeAliases> <package name="sample.mybatis.domain"/> </typeAliases> <mappers> <mapper resource="sample/mybatis/mapper/CityMapper.xml"/> <mapper resource="sample/mybatis/mapper/HotelMapper.xml"/> </mappers> </configuration>
例子2(通过 mybatis.type-aliases-package 和 @Mapper 来配置mybatis):
#application.properties
mybatis.type-aliases-package=com.expert.pojo
package com.expert.dao;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
import com.expert.pojo.User;
@Mapper
public interface UserMapper {
// @Select("SELECT * FROM user WHERE id = #{ id }")
User getById(String id);
@Select("SELECT * FROM user WHERE id = #{ id }")
User getById2(String id);
}
注意:@Alias("xxx") 是用来设置别名,而非用于扫描。
posted on 2016-09-15 00:46 LarryZeal 阅读(53253) 评论(0) 编辑 收藏 举报