Springboot整合Mybatis实现Druid多数据源

本例将采用maven管理，代码托管在github上，地址：https://github.com/wolf909867753/springboot。

1。创建maven-module，mybatis-mutil-datasource,并在pom.xml中添加springboot依赖

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <parent>
<artifactId>spring-boot-starter-parent</artifactId>
<groupId>org.springframework.boot</groupId>
<version>1.5.1.RELEASE</version>
</parent>

<modelVersion>4.0.0</modelVersion>
<artifactId>mybatis-mutil-datasource</artifactId>
<packaging>war</packaging>
<name>Spring Boot整合Mybatis实现Druid多数据源</name>
<url>http://maven.apache.org</url>

<properties>
<mybatis-spring-boot>1.2.0</mybatis-spring-boot>
<mysql-spring-boot>5.1.32</mysql-spring-boot>
<druid>1.0.18</druid>
</properties>

<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>

<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>${mybatis-spring-boot}</version>
</dependency>

<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>${mysql-spring-boot}</version>
</dependency>

<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>${druid}</version>
</dependency>

<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<finalName>mybatis-mutil-datasource</finalName>
</build>
</project>

1.项目结构介绍

    com.springboot.dataSourceConfig – 配置层，这里是数据源的配置，包括 master 和 cluster 的数据源配置
    

/**
* @Primary 标志这个 Bean 如果在多个同类 Bean 候选时，该 Bean 优先被考虑。「多数据源配置的时候注意，必须要有一个主数据源，用 @Primary 标志该 Bean」
* @MapperScan 扫描 Mapper 接口并容器管理，包路径精确到 master，为了和下面 cluster 数据源做到精确区分
* @Value 获取全局配置文件 application.properties 的 kv 配置,并自动装配
* sqlSessionFactoryRef 表示定义了 key ，表示一个唯一 SqlSessionFactory 实例
* Created by wanglu-jf on 17/6/28.
*/
@Configuration
@MapperScan(basePackages = ClusterConfig.PACKAGE,sqlSessionFactoryRef = "clusterSqlSessionFactory")
public class ClusterConfig {

public static final String PACKAGE = "com.springboot.dao.cluster";

public static final String MAPPER_LOCATION = "classpath:mapper/cluster/*.xml";

//    cluster.datasource.driver-class-name = com.mysql.jdbc.Driver
//    cluster.datasource.url = jdbc:mysql://localhost:3306/springbootdb_cluster?useUnicode=true&characterEncoding=utf8
//    cluster.datasource.username = root
//    cluster.datasource.password = root

@Value("${cluster.datasource.driver-class-name}")
private String driverClassName;

@Value("${cluster.datasource.url}")
private String url;

@Value("${cluster.datasource.username}")
private String username;

@Value("${cluster.datasource.password}")
private String password;

//初始化数据库连接
@Bean(name="clusterDataSource")
public DataSource clusterDataSource(){
DruidDataSource dataSource = new DruidDataSource();
dataSource.setDriverClassName(driverClassName);
dataSource.setUrl(url);
dataSource.setUsername(username);
dataSource.setPassword(password);
return dataSource;
}

//数据源事务管理器
@Bean(name="clusterDataSourceTransactionManager")
public DataSourceTransactionManager clusterDataSourceTransactionManager(){
DataSourceTransactionManager dataSourceTransactionManager = new DataSourceTransactionManager();
dataSourceTransactionManager.setDataSource(clusterDataSource());
return dataSourceTransactionManager;
}

//创建Session
@Bean(name="clusterSqlSessionFactory")
public SqlSessionFactory clusterSqlSessionFactory(@Qualifier("clusterDataSource") DataSource clusterDataSource) throws Exception{
final SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
sqlSessionFactoryBean.setDataSource(clusterDataSource);
Resource[] resource = new PathMatchingResourcePatternResolver().getResources(ClusterConfig.MAPPER_LOCATION);
sqlSessionFactoryBean.setMapperLocations(resource);
return sqlSessionFactoryBean.getObject();
}
}

@Configuration
// 扫描 Mapper 接口并容器管理
@MapperScan(basePackages = MasterConfig.PACKAGE,sqlSessionFactoryRef = "masterSqlSessionFactory")
public class MasterConfig {

//master dao 所在的包
public static final String PACKAGE = "com.springboot.dao.master";

//mapper所在目录
private static final String MAPPER_LOCATION = "classpath:mapper/master/*.xml";

//    master.datasource.driver-class-name = com.mysql.jdbc.Driver
//    master.datasource.url = jdbc:mysql://localhost:3306/springbootdb?useUnicode=true&characterEncoding=utf8
//    master.datasource.username = root
//    master.datasource.password = root

@Value("${master.datasource.driver-class-name}")
private String driverClassName;

@Value("${master.datasource.url}")
private String url;

@Value("${master.datasource.username}")
private String username;

@Value("${master.datasource.password}")
private String password;

//初始化数据库连接
@Bean(name="masterDataSource")
@Primary
public DataSource masterDataSource(){
DruidDataSource dataSource = new DruidDataSource();
dataSource.setDriverClassName(driverClassName);
dataSource.setUrl(url);
dataSource.setUsername(username);
dataSource.setPassword(password);
return dataSource;
}

//数据源事务管理器
@Bean(name="masterDataSourceTransactionManager")
@Primary
public DataSourceTransactionManager masterDataSourceTransactionManager(){
return new DataSourceTransactionManager(masterDataSource());
}

//创建Session
@Bean(name="masterSqlSessionFactory")
@Primary
public SqlSessionFactory masterSqlSessionFactory(@Qualifier("masterDataSource") DataSource masterDataSource) throws Exception{
final SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
sqlSessionFactoryBean.setDataSource(masterDataSource);
//MapperLocations(Resource[] mapperLocations)
Resource[] mapperLocations = new PathMatchingResourcePatternResolver().getResources(MasterConfig.MAPPER_LOCATION);
sqlSessionFactoryBean.setMapperLocations(mapperLocations);
return sqlSessionFactoryBean.getObject();
}

}

    
    com.springboot.controller – Controller 层
    
    

@RestController
@RequestMapping("user/")
public class UserController {

@Autowired
private IUserService userService;

@RequestMapping(value="query/{id}",method = RequestMethod.GET)
public User queryById(@PathVariable("id") int id){
User user = this.userService.queryById(id);
return user;
}
}

    com.springboot.dao – 数据操作层 DAO，细分了 master 和 cluster 包下的 DAO 操作类
    
    

@Mapper
public interface IUserDao {

/**
* 根据用户id获取用户信息
*
* @param userId
* @return
*/
public User queryByUserId(@Param("userId") int userId);
}

@Mapper
public interface ICityDao {

/**
* 根据城市名称，查询城市信息
*
* @param cityId 城市名
*/
public City queryById(@Param("cityId") int cityId);
}

    com.springboot.domain – 实体类
    

public class City implements Serializable{

/**
* 城市编号
*/
private Long id;

/**
* 省份编号
*/
private Long provinceId;

/**
* 城市名称
*/
private String cityName;

/**
* 描述
*/
private String description;

getter/setter.... }

public class User {

/**
* 城市编号
*/
private Long id;

/**
* 城市名称
*/
private String userName;

/**
* 描述
*/
private String description;

getter/setter....
}

    
    com.springboot.service – 业务逻辑层
    

public interface IUserService {
/**
* 根据用户id获取用户信息，包括从库的地址信息
* @param userId
* @return
*/
public User queryById(int userId);
}

@Service
public class UserServiceImpl implements IUserService {

@Autowired
private IUserDao userDao; // user数据源
@Autowired
private ICityDao cityDao; //city数据源

/**
* 根据用户id获取用户信息，包括从库的地址信息
* @param id
* @return
*/
@Override
public User queryById(int id) {
User user = this.userDao.queryByUserId(id);
City city = this.cityDao.queryById(id);
if(null != user && null != city){
user.setCity(city);
}
return user;
}
}

    
    Application – 应用启动类
    

@SpringBootApplication
public class Application {

public static void main(String[] args) {
SpringApplication.run(Application.class,args);
}
}

    
    application.properties – 应用配置文件，应用启动会自动读取配置
    

## master 数据源配置
master.datasource.driver-class-name = com.mysql.jdbc.Driver
master.datasource.url = jdbc:mysql://localhost:3306/springbootdb?useUnicode=true&characterEncoding=utf8
master.datasource.username = root
master.datasource.password = root

## cluster 数据源配置
cluster.datasource.driver-class-name = com.mysql.jdbc.Driver
cluster.datasource.url = jdbc:mysql://localhost:3306/springbootdb_cluster?useUnicode=true&characterEncoding=utf8
cluster.datasource.username = root
cluster.datasource.password = root

    
2.改数据库配置
    打开 application.properties 文件，配置主从数据源地址、账号、密码等。
    
 mapper配置文件

<?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.springboot.dao.cluster.IUserDao">
<resultMap id="BaseResultMap" type="com.springboot.domain.User">
<result column="id" property="id" />
<result column="user_name" property="userName" />
<result column="description" property="description" />
</resultMap>

<parameterMap id="user" type="com.springboot.domain.User"/>

<sql id="Base_Column_List">
id, user_name, description
</sql>

<select id="queryByUserId" resultMap="BaseResultMap" parameterType="int">
select
<include refid="Base_Column_List" />
from user
where id = #{userId}
</select>

</mapper>

<?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.springboot.dao.master.ICityDao">
<resultMap id="BaseResultMap" type="com.springboot.domain.City">
<result column="id" property="id" />
<result column="province_id" property="provinceId" />
<result column="city_name" property="cityName" />
<result column="description" property="description" />
</resultMap>

<parameterMap id="City" type="com.springboot.domain.City"/>

<sql id="Base_Column_List">
id, province_id, city_name, description
</sql>

<select id="queryById" resultMap="BaseResultMap" parameterType="int">
select
<include refid="Base_Column_List" />
from city
where id = #{cityId}
</select>

</mapper>

   
3.运行Application的main方法，启动成功后
    访问http://127.0.0.1:8080/user/query/1
    输出
    {"id":1,"userName":"wolf","description":"https://github.com/wolf909867753/springboot","city":{"id":1,"provinceId":1,"cityName":"潍坊市","description":"我的家在山东省潍坊市。"}}