【基础版】Springboot2.x+Mybatis配置多数据源
网上大多数教程都是比较老的版本（Springboot1.x），很多方法已经因升级而不再被支持，我经过实践，找到了一种比较简单的方案来配置多数据源，基本可以直接放在自己的项目中修改使用。
如何建立Springboot项目等过程我就不赘述了，相信看到这篇文章的你已经熟练掌握，我只写一下配置的方式以及简单的功能实现。
项目的部分pom.xml简单列出来大家参考一下。
org.springframework.boot
spring-boot-starter-parent
2.0.4.RELEASE
org.mybatis.spring.boot
mybatis-spring-boot-starter
1.3.2
mysql
mysql-connector-java
runtime
com.alibaba
druid-spring-boot-starter
1.1.10
我们在application.yml中配置多数据源的基本信息，注意，配置多数据源时不要配置spring.datasource，连接池我用的是阿里的druid，没有的话可以用默认的。
另外，在springboot2.x中配置多数据源时，原来的url部分要用jdbc-url，否则会报错java.lang.IllegalArgumentException: jdbcUrl is required with driverClassName.
application.yml配置多数据源
market: # 市场数据库
datasource:
driver-class-name: com.mysql.jdbc.Driver
jdbc-url: jdbc:mysql://127.0.0.1:3306/market?useUnicode=true&characterEncoding=UTF-8&useSSL=false
username: root
password: 123456
type: com.alibaba.druid.pool.DruidDataSource
trade: # 交易数据库
datasource:
driver-class-name: com.mysql.jdbc.Driver
jdbc-url: jdbc:mysql://127.0.0.1:3306/trade?useUnicode=true&characterEncoding=UTF-8&useSSL=false
username: root
password: 123456
type: com.alibaba.druid.pool.DruidDataSource完整的application.yml
spring:
profiles:
active: dev
mybatis:
configuration:
cache-enabled: false
map-underscore-to-camel-case: true
use-generated-keys: true
default-executor-type: reuse
default-statement-timeout: 600
redis:
database: 0
host: 127.0.0.1
port: 6379
password: 1234
pool:
max-active: 8
max-wait: -1
max-idle: 8
min-idle: 0
timeout: 0
market: # 市场数据库
datasource:
driver-class-name: com.mysql.jdbc.Driver
jdbc-url: jdbc:mysql://127.0.0.1:3306/market?useUnicode=true&characterEncoding=UTF-8&useSSL=false
username: root
password: 123456
type: com.alibaba.druid.pool.DruidDataSource
trade: # 交易数据库
datasource:
driver-class-name: com.mysql.jdbc.Driver
jdbc-url: jdbc:mysql://127.0.0.1:3306/trade?useUnicode=true&characterEncoding=UTF-8&useSSL=false
username: root
password: 123456
type: com.alibaba.druid.pool.DruidDataSource接下来是让springboot找到我们的配置，并配置多连接
新建MultipleDBConfig.java（建议放在config包中）
MultipleDBConfig.java
import javax.sql.DataSource;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.jdbc.DataSourceBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.jdbc.core.JdbcTemplate;
@Configuration
public class MultipleDBConfig {
@Bean(name = "market")
@Primary
@ConfigurationProperties(prefix = "market.datasource")
public DataSource marketDataSource() {
return DataSourceBuilder.create().build();
}
@Bean(name = "marketJdbcTemplate")
public JdbcTemplate marketJdbcTemplate(@Qualifier("market") DataSource dsMarket) {
return new JdbcTemplate(dsMarket);
}
@Bean(name = "trade")
@ConfigurationProperties(prefix = "trade.datasource")
public DataSource tradeDataSource() {
return DataSourceBuilder.create().build();
}
@Bean(name = "tradeJdbcTemplate")
public JdbcTemplate tradeJdbcTemplate(@Qualifier("trade")
DataSource dsTrade) {
return new JdbcTemplate(dsTrade);
}
}此处要注意，@ConfigurationProperties注解配置的是在application.yml中编辑的数据源信息的前缀，切记，需要在一个数据源加上@Primary注解，否则会提示发现多个数据源而无法启动（如下图）
***************************
APPLICATION FAILED TO START
***************************
Description:
Parameter 0 of method sqlSessionFactory in org.mybatis.spring.boot.autoconfigure.MybatisAutoConfiguration required a single bean, but 2 were found:
- market: defined by method 'marketDataSource' in class path resource [com/finanstar/fx/config/MultipleDBConfig.class]
- trade: defined by method 'tradeDataSource' in class path resource [com/finanstar/fx/config/MultipleDBConfig.class]
Action:
Consider marking one of the beans as @Primary, updating the consumer to accept multiple beans, or using @Qualifier to identify the bean that should be consumed配置基本到这里就结束了，下面来看一下我们配置后的效果，我们在controller中简单写两个方法来测试一下：
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
@RestController
@RequestMapping("/hello")
public class HelloController {
@Autowired
@Qualifier("marketJdbcTemplate")
private JdbcTemplate marketTemplate;
@Autowired
@Qualifier("tradeJdbcTemplate")
private JdbcTemplate tradeTemplate;
private final static Logger logger = LoggerFactory.getLogger(HelloController.class);
@GetMapping(value = "/getMarketUser")
public String getPGUser() {
Map map = new HashMap();
String query = " select * from user where id='20180903001'";
try {
// 每条记录对应一个Map，当只返回一条数据时用queryForMap即可
map = marketTemplate.queryForMap(query);
} catch (Exception e) {
e.printStackTrace();
}
return "Marke Data: " + map.toString();
}
@GetMapping(value = "/getTradeUser")
public String getMYUser() {
List> list = new ArrayList>();
String query = " select * from user";
try {
// 如果返回多条数据需要用queryForList方法，并用一个泛型为Map的List来接收
list = tradeTemplate.queryForList(query);
} catch (Exception e) {
e.printStackTrace();
}
return "Trade Data: " + list.toString();
}
}
此时启动Springboot项目，在浏览器访问http://{ip}:{port}/hello/getMarketUser或http://{ip}:{port}/hello/getTradeUser即可看到我们的结果。
更多方式请留意后续更新，这次只是一个基础版本，还有更多更加方便的方式来选择，比如通过aop来进行数据源的动态切换等。