CH13-多数据源
如果要在查询端实现数据库的主从访问,或者业务较复杂,需要访问不同的数据库,则需要实现多数据源的集成与切换。
配置文件
mybatis.config-location=classpath:mybatis/mybatis-config.xml
spring.datasource.test1.jdbc-url=jdbc:mysql://localhost:3306/test1?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
spring.datasource.test1.username=root
spring.datasource.test1.password=root
spring.datasource.test1.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.test2.jdbc-url=jdbc:mysql://localhost:3306/test2?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
spring.datasource.test2.username=root
spring.datasource.test2.password=root
spring.datasource.test2.driver-class-name=com.mysql.cj.jdbc.Driver
一个 test1 库和一个 test2 库,其中 test1 位主库,在使用的过程中必须指定主库,不然会报错。
数据源配置
@Configuration
@MapperScan(basePackages = "com.neo.mapper.test1", sqlSessionTemplateRef = "test1SqlSessionTemplate")
public class DataSource1Config {
@Bean(name = "test1DataSource")
@ConfigurationProperties(prefix = "spring.datasource.test1")
@Primary
public DataSource testDataSource() {
return DataSourceBuilder.create().build();
}
@Bean(name = "test1SqlSessionFactory")
@Primary
public SqlSessionFactory testSqlSessionFactory(@Qualifier("test1DataSource") DataSource dataSource) throws Exception {
SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
bean.setDataSource(dataSource);
bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mybatis/mapper/test1/*.xml"));
return bean.getObject();
}
@Bean(name = "test1TransactionManager")
@Primary
public DataSourceTransactionManager testTransactionManager(@Qualifier("test1DataSource") DataSource dataSource) {
return new DataSourceTransactionManager(dataSource);
}
@Bean(name = "test1SqlSessionTemplate")
@Primary
public SqlSessionTemplate testSqlSessionTemplate(@Qualifier("test1SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
return new SqlSessionTemplate(sqlSessionFactory);
}
}
最关键的地方就是这块了,一层一层注入,首先创建 DataSource,然后创建 SqlSessionFactory 再创建事务,最后包装到 SqlSessionTemplate 中。其中需要指定分库的 mapper 文件地址,以及分库dao层代码:
@MapperScan(basePackages = "com.neo.mapper.test1", sqlSessionTemplateRef = "test1SqlSessionTemplate")
这块的注解就是指明了扫描 dao 层,并且给 dao 层注入指定的 SqlSessionTemplate。所有@Bean
都需要按照命名指定正确。
dao & mapper
dao 层和 xml 需要按照库来分在不同的目录,比如:test1 库 dao 层在 com.neo.mapper.test1
包下,test2 库在com.neo.mapper.test2
:
public interface User1Mapper {
List<UserEntity> getAll();
UserEntity getOne(Long id);
void insert(UserEntity user);
void update(UserEntity user);
void delete(Long id);
}
mapper:
<mapper namespace="com.neo.mapper.test1.User1Mapper" >
<resultMap id="BaseResultMap" type="com.neo.model.User" >
<id column="id" property="id" jdbcType="BIGINT" />
<result column="userName" property="userName" jdbcType="VARCHAR" />
<result column="passWord" property="passWord" jdbcType="VARCHAR" />
<result column="user_sex" property="userSex" javaType="com.neo.enums.UserSexEnum"/>
<result column="nick_name" property="nickName" jdbcType="VARCHAR" />
</resultMap>
<sql id="Base_Column_List" >
id, userName, passWord, user_sex, nick_name
</sql>
<select id="getAll" resultMap="BaseResultMap" >
SELECT
<include refid="Base_Column_List" />
FROM users
</select>
<select id="getOne" parameterType="java.lang.Long" resultMap="BaseResultMap" >
SELECT
<include refid="Base_Column_List" />
FROM users
WHERE id = #{id}
</select>
<insert id="insert" parameterType="com.neo.model.User" >
INSERT INTO
users
(userName,passWord,user_sex)
VALUES
(#{userName}, #{passWord}, #{userSex})
</insert>
<update id="update" parameterType="com.neo.model.User" >
UPDATE
users
SET
<if test="userName != null">userName = #{userName},</if>
<if test="passWord != null">passWord = #{passWord},</if>
nick_name = #{nickName}
WHERE
id = #{id}
</update>
<delete id="delete" parameterType="java.lang.Long" >
DELETE FROM
users
WHERE
id =#{id}
</delete>
</mapper>
测试验证
测试可以使用 SpringBootTest,也可以放到 Controller中,这里只贴 Controller 层的使用:
@RestController
public class UserController {
@Autowired
private User1Mapper user1Mapper;
@Autowired
private User2Mapper user2Mapper;
@RequestMapping("/getUsers")
public List<UserEntity> getUsers() {
List<UserEntity> users=user1Mapper.getAll();
return users;
}
@RequestMapping("/getUser")
public UserEntity getUser(Long id) {
UserEntity user=user2Mapper.getOne(id);
return user;
}
@RequestMapping("/add")
public void save(UserEntity user) {
user2Mapper.insert(user);
}
@RequestMapping(value="update")
public void update(UserEntity user) {
user2Mapper.update(user);
}
@RequestMapping(value="/delete/{id}")
public void delete(@PathVariable("id") Long id) {
user1Mapper.delete(id);
}
}
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