mybatis自动切换多个数据源

假设现在有两个数据库myone和mytwo,读者可以理解为一个写库,一个读库,数据库中都各自有一个表,表的格式都一样，如下：

------------------------------------------------------------
id         int(11) PRI auto_increment
username varchar(20)
password varchar(20)
------------------------------------------------------------

数据库脚本如下：

create database myone;
use myone;
create table user(id int auto_increment primary key,username varchar(20),password varchar(20));

create database mytwo;
use mytwo;
create table user(id int auto_increment primary key,username varchar(20),password varchar(20));
insert into mytwo.user(username,password) value('test','test');

 

现在想要实现数据库的自动切换，有些mapper操作写库myone，有些mapper操作读库mytwo。
首先，构建maven工程，pom文件如下：

 

 

    4.0.0

    com.aliyun.security
    resourcegroup
    1.0-SNAPSHOT

    
        
        
            org.apache.commons
            commons-dbcp2
            2.1.1
        
        
        
            org.mybatis
            mybatis
            3.2.8
        
        
        
            org.springframework
            spring-jdbc
            4.1.6.RELEASE
        

        
        
            org.springframework
            spring-aop
            4.1.6.RELEASE
        
        
        
            org.springframework
            spring-context
            4.1.6.RELEASE
        
        
        
            org.aspectj
            aspectjweaver
            1.8.6
        
        
        
            org.mybatis
            mybatis-spring
            1.1.1
        

        
        
            mysql
            mysql-connector-java
            5.1.38
        
    

接下来是写库myone对应的mapper，如下：

 

package dal.mapper.myone;

import dal.dataobject.myone.User;

public interface OneUserManageMapper {
    int createUser(User user);
}

 

 

 

	
		INSERT INTO user(username, password) VALUES(#{username}, #{password})
	

 

接下来是读库mytwo对应的mapper，如下：

 

 

package dal.mapper.mytwo;

import dal.dataobject.mytwo.User;
import org.apache.ibatis.annotations.Param;

public interface TwoUserManageMapper {
    User getUserById(@Param("id") int id);
}

 

 

 

	
		
	
	
		
		
		
	
	
		SELECT * from user WHERE id=#{id}
	

 

接下来是实现自动切换最主要的代码，这里使用AOP编程来实现：

 

 

package dal.datasourceswitch;

import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
/**
 * Created by Administrator on 2016/8/22.
 */

/**
 * Created by rabbit on 14-5-25.
 */
public class MultipleDataSource extends AbstractRoutingDataSource {

    private static ThreadLocal threadLocalDatasource=new ThreadLocal(){
        @Override
        protected String initialValue() {
            return null;
        }
    };

    public static void setThreadLocalDatasource(String dsName){
        threadLocalDatasource.set(dsName);
    }


    @Override
    protected Object determineCurrentLookupKey() {
        return threadLocalDatasource.get();
    }
}

 

 

 

package dal.datasourceswitch;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;

@Component
@Aspect
public class MultipleDataSourceAspectAdvice {

    @Around("execution(* dal.mapper.myone..*.*(*))")
    public Object doAround1(ProceedingJoinPoint jp) throws Throwable {
        MultipleDataSource.setThreadLocalDatasource("myone");
        return jp.proceed();
    }

    @Around("execution(* dal.mapper.mytwo..*.*(*))")
    public Object doAround2(ProceedingJoinPoint jp) throws Throwable {
        MultipleDataSource.setThreadLocalDatasource("mytwo");
        return jp.proceed();
    }

}

 

读者可以学习下AbstractRoutingDataSource类，就知道这么做的理由了。
最后，看下spring的配置文件：

 

 

    
        
            jdbc.properties
        
    
    
        
        
        
        
    
    
        
        
        
        
    

    
         
        
            
        
    

    
        
        
            
                mapper/OneUserManageMapper.xml
                mapper/TwoUserManageMapper.xml
            
        
    


    
        
    

    
        
    

    
        
    
    
    
     
      

上面是实现多数据源自动切换的主要代码，源码github地址：
https://github.com/ZhenShiErGe/Multi-Datasource-Autoswitch.git

 

 

文章修改自http://www.cnblogs.com/lzrabbit/p/3750803.html

 

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