详解springboot+mybatis多数据源最简解决方案_Java教程

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。我们项目是后者的模式，网上找了很多，大都是根据jpa来做多数据源解决方案，要不就是老的spring多数据源解决方案，还有的是利用aop动态切换，感觉有点小复杂，其实我只是想找一个简单的多数据支持而已，折腾了两个小时整理出来，供大家参考。

废话不多说直接上代码吧

配置文件

pom包就不贴了比较简单该依赖的就依赖，主要是数据库这边的配置：

									mybatis.config-locations=classpath:mybatis/mybatis-config.xml

									spring.datasource.test1.driverClassName = com.mysql.jdbc.Driver

									spring.datasource.test1.url = jdbc:mysql://localhost:3306/test1?useUnicode=true&characterEncoding=utf-8

									spring.datasource.test1.username = root

									spring.datasource.test1.password = root

									spring.datasource.test2.driverClassName = com.mysql.jdbc.Driver

									spring.datasource.test2.url = jdbc:mysql://localhost:3306/test2?useUnicode=true&characterEncoding=utf-8

									spring.datasource.test2.username = root

									spring.datasource.test2.password = root

一个test1库和一个test2库，其中test1位主库，在使用的过程中必须制定主库，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,先创建DataSource，在创建SqlSessionFactory在创建事务，最后包装到SqlSessionTemplate中。其中需要制定分库的mapper文件地址，以及分库到层代码

复制代码代码如下:

	

	@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.neo.mapper.test1包下，test2库在com.neo.mapper.test1

									public interface User1Mapper {

									  List<UserEntity> getAll();

									  UserEntity getOne(Long id);

									  void insert(UserEntity user);

									  void update(UserEntity user);

									  void delete(Long id);

									}

xml层

									<?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.neo.mapper.test1.User1Mapper" >

									  <resultMap id="BaseResultMap" type="com.neo.entity.UserEntity" >

									    <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.entity.UserEntity" >

									    INSERT INTO 

									      users

									      (userName,passWord,user_sex) 

									    VALUES

									      (#{userName}, #{passWord}, #{userSex})

									  </insert>

									  <update id="update" parameterType="com.neo.entity.UserEntity" >

									    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);

									  }

									}