spring boot mybatis多数据源，后端进行数据库读写分离

1.注意了读写分离在后端进行操作，写，更新在一个数据库服务器，而读在另一个数据库服务器上。至于2个数据库怎么保持一致，可以看下我之前博客http://blog.csdn.net/weixin_38336658/article/details/79195210

2.后端的读写分离很简单，主要是配置数据库的难题。为啥简单？只要数据库配置好，你想哪个数据库写，哪个数据库读，自己安排

1）看下application.properties

#spring.datasource.name= test
#spring.datasource.url= jdbc:mysql://127.0.0.1:3306/demo
#spring.datasource.username= root
#spring.datasource.password= 123456

spring.datasource.test1.driverClassName = com.mysql.jdbc.Driver
spring.datasource.test1.url = jdbc:mysql://localhost:3306/demo?useUnicode=true&characterEncoding=utf-8
spring.datasource.test1.username = root
spring.datasource.test1.password = 123456

spring.datasource.test2.driverClassName = com.mysql.jdbc.Driver
spring.datasource.test2.url = jdbc:mysql://192.168.134.129:3306/demo?useUnicode=true&characterEncoding=utf-8
spring.datasource.test2.username = root
spring.datasource.test2.password = 123456上面#的是注释，其实是spring boot项目原本的数据库配置，默认的
下面是2个自己创建的数据库配置

2）数据库的相关配置

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.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;

@Configuration
@MapperScan(basePackages = "com.example.demo.dao", 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:mapping/*.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);
}

}看见上面红色的没有，其实当时我有个疑问，你配置完2个数据库，那系统怎么知道你要用那个数据库呢。就是上面红色这个。这个是扫描你这个数据库相应的dao类
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.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import javax.sql.DataSource;

@Configuration
@MapperScan(basePackages = "com.example.demo.dao2", 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:mapping2/*.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);
}

}


其次接下来怎么做？跟你平时mybatis项目没什么两样，我用的是数据库然后再用mybatis插件生成mapper类http://blog.csdn.net/weixin_38336658/article/details/78673600
然后自己玩得happy咯，鸡腿不再往下讲其他无关的了

3.很多博客都没有发项目结构截图，你写的一些细节，其他读者怎么知道是什么东东对吧。向刚刚上面提到的红字重点，com.example.dao2,大家可以在下面看下