Spring Boot 整合多数据源

Spring Boot 整合多数据源

我们先创建一个maven项目：



创建两个数据库test01和test02，并且都创建一个user表

配置pom.xml

<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/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion>
<groupId>com.cc.springboot</groupId>
<artifactId>springboot-many-mybatis</artifactId>
<version>0.0.1-SNAPSHOT</version>

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.3.2.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>

<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.1.1</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
</project>

配置文件中新增两个数据源

application.properties

spring.datasource.test1.driverClassName = com.mysql.jdbc.Driver
spring.datasource.test1.url = jdbc:mysql://localhost:3306/test01?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/test02?useUnicode=true&characterEncoding=utf-8
spring.datasource.test2.username = root
spring.datasource.test2.password = root

创建分包Mapper

分包创建User1Mapper和User2Mapper

package com.cc.springboot.test01;

import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Param;

public interface User1Mapper {

@Insert("insert into users values(#{id},#{username});")
public int addUser(@Param("id") Integer id, @Param("username") String username);

}

package com.cc.springboot.test02;

import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Param;

public interface User2Mapper {

@Insert("insert into users values(#{id},#{username});")
public int addUser(@Param("id") Integer id, @Param("username") String username);
}

配置文件中新增两个数据源

package com.cc.springboot.datasource;

import javax.sql.DataSource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

@Configuration // 注册到springboot容器中
@MapperScan(basePackages = "com.cc.springboot.test01", sqlSessionFactoryRef = "test1SqlSessionFactory")
public class DataSource1Config {

/**
*配置test1数据库
*/
@Bean(name = "test1DataSource")
@Primary
@ConfigurationProperties(prefix = "spring.datasource.test1")
public DataSource testDataSource() {
return DataSourceBuilder.create().build();
}

/*
* test1 sql会话工厂
*/
@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();
}

/**
*test1 事物管理
*/
@Bean(name = "test1TransactionManager")
@Primary
public DataSourceTransactionManager testTransactionManager(@Qualifier("test1DataSource") DataSource dataSource) {
return new DataSourceTransactionManager(dataSource);
}

@Bean(name = "test1SqlSessionTemplate")
public SqlSessionTemplate testSqlSessionTemplate(
@Qualifier("test1SqlSessionFactory") SqlSessionFactory sqlSessionFactory) throws Exception {
return new SqlSessionTemplate(sqlSessionFactory);
}

}

package com.cc.springboot.datasource;

import javax.sql.DataSource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.jdbc.DataSourceBuilder;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

@Configuration // 注册到springboot容器中
@MapperScan(basePackages = "com.cc.springboot.test02", sqlSessionFactoryRef = "test2SqlSessionFactory")
public class DataSource2Config {

/**
*配置test2数据库
*/
@Bean(name = "test2DataSource")
@ConfigurationProperties(prefix = "spring.datasource.test2")
public DataSource testDataSource() {
return DataSourceBuilder.create().build();
}

/*
* test2 sql会话工厂
*/
@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();
}

/**
*test2 事物管理
*/
@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);
}

}

分包创建service

package com.cc.springboot.service.test01;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.cc.springboot.test01.User1Mapper;

@Service
public class User1Service {
@Autowired
private User1Mapper user1Mapper;

public int addUser(Integer id, String name) {
return user1Mapper.addUser(id, name);
}

}

package com.cc.springboot.service.test02;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import com.cc.springboot.test02.User2Mapper;

@Service
public class User2Service {
@Autowired
private User2Mapper user2Mapper;

public int addUser(Integer id, String name) {
return user2Mapper.addUser(id, name);
}

}

创建Controller

package com.cc.springboot.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.cc.springboot.service.test01.User1Service;
import com.cc.springboot.service.test02.User2Service;

@RestController
public class IndexController {
@Autowired
private User1Service user1Service;
@Autowired
private User2Service user2Service;

@RequestMapping("/add")
public String index() {
user1Service.addUser(1,"db user001");
user2Service.addUser(2,"db user002");
return "success";
}

}

创建启动类

package com.cc.springboot.app;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;

@ComponentScan(basePackages = {"com.cc.springboot.controller","com.cc.springboot.test01","com.cc.springboot.test02","com.cc.springboot.service","com.cc.springboot.datasource"})
@EnableAutoConfiguration
public class App {
public static void main(String[] args) {
SpringApplication.run(App.class, args);
}
}

测试

启动：

注意事项

如果去掉DataSource1Config配置中的@Primary会发生什么？?



发现报错了：



错误原因：No qualifying bean of type [javax.sql.DataSource] is defined: expected single matching bean but found 2: test1DataSource,test2DataSource

给其中一个数据源加上@Primary。因为在Spring Boot Jdbc的自动配置过程中，会对于开发者透明地使用dataSource进行一些相关配置，所以当有两个Datasource实现类时，Spring Boot将无法确定使用哪一个。

DataSource1Config配置中的注解的具体解释：

@Primary：指定在同一个接口有多个实现类可以注入的时候，默认选择哪一个，而不是让@Autowire注解报错（一般用于多数据源的情况下）

@Qualifier：指定名称的注入，当一个接口有多个实现类的时候使用（在本例中，有两个DataSource类型的实例，需要指定名称注入）

@Bean：生成的bean实例的名称是方法名（例如上边的@Qualifier注解中使用的名称是前边两个数据源的方法名，而这两个数据源也是使用@Bean注解进行注入的）