springboot之mybatis多数据源最简解决方案
说起多数据源，一般都来解决那些问题呢，主从模式或者业务比较复杂需要连接不同的分库来支持业务。
我们以 Mybatis Xml 版本为例，给大家展示如何如何配置多数据源。
目录结构
使用到的依赖
pom.xml
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.0.0</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
配置文件
application.properties
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 为主库，在使用的过程中必须指定主库，不然会报错。
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> <typeAlias alias="Integer" type="java.lang.Integer" /> <typeAlias alias="Long" type="java.lang.Long" /> <typeAlias alias="HashMap" type="java.util.HashMap" /> <typeAlias alias="LinkedHashMap" type="java.util.LinkedHashMap" /> <typeAlias alias="ArrayList" type="java.util.ArrayList" /> <typeAlias alias="LinkedList" type="java.util.LinkedList" /> </typeAliases> </configuration>
数据源配置
DataSource1Config.java
@Configuration @MapperScan(basePackages = "com.vincent.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。
DataSource2Config.java
@Configuration @MapperScan(basePackages = "com.vincent.mapper.test2", sqlSessionTemplateRef = "test2SqlSessionTemplate") public class DataSource2Config { @Bean(name = "test2DataSource") @ConfigurationProperties(prefix = "spring.datasource.test2") public DataSource testDataSource() { return DataSourceBuilder.create().build(); } @Bean(name = "test2SqlSessionFactory") public SqlSessionFactory testSqlSessionFactory(@Qualifier("test2DataSource") DataSource dataSource) throws Exception { SqlSessionFactoryBean bean = new SqlSessionFactoryBean(); bean.setDataSource(dataSource); bean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:mybatis/mapper/test2/*.xml")); return bean.getObject(); } @Bean(name = "test2TransactionManager") public DataSourceTransactionManager testTransactionManager(@Qualifier("test2DataSource") DataSource dataSource) { return new DataSourceTransactionManager(dataSource); } @Bean(name = "test2SqlSessionTemplate") public SqlSessionTemplate testSqlSessionTemplate(@Qualifier("test2SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception { return new SqlSessionTemplate(sqlSessionFactory); } }
dao 层和 xml层
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.vincent.mapper.test1 包下，test2 库在com.vincent.mapper.test2
User1Mapper.java
public interface User1Mapper { List<UserEntity> getAll(); UserEntity getOne(Long id); void insert(UserEntity user); void update(UserEntity user); void delete(Long id); }
User2Mapper.java
public interface User2Mapper { List<User> getAll(); User getOne(Long id); void insert(User user); void update(User user); void delete(Long id); }
xml 层
配置文件目录结构
test1/UserMapper.xml
<?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.vincent.mapper.test1.User1Mapper" > <resultMap id="BaseResultMap" type="com.vincent.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.vincent.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.vincent.model.User" > INSERT INTO users (userName,passWord,user_sex) VALUES (#{userName}, #{passWord}, #{userSex}) </insert> <update id="update" parameterType="com.vincent.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>
test2/UserMapper.xml
<?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.vincent.mapper.test2.User2Mapper" >
<resultMap id="BaseResultMap" type="com.vincent.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.vincent.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.vincent.model.User" >
INSERT INTO
users
(userName,passWord,user_sex)
VALUES
(#{userName}, #{passWord}, #{userSex})
</insert>
<update id="update" parameterType="com.vincent.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
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); } }
Mybatis 注解版本配置多数据源和 Xml 版本基本一致，搭建可以参考文末的示例项目。
