- maven引入依赖jar
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.1.1</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.9</version>
</dependency>
- 多个数据源配置
@Configuration
public class StudyConfiguration {
@Bean(name = "readDataSouce")
@ConfigurationProperties(prefix = "spring.primary.druid")
public DataSource readDataSouce() {
return new DruidDataSource();
}
@Bean(name = "writeDataSouce")
@ConfigurationProperties(prefix = "spring.secondary.druid")
public DataSource writeDataSouce() {
return new DruidDataSource();
}
}
- 属性文件配置applicatin.properties
spring.primary.druid.url=jdbc:mysql://localhost:3306/database?useUnicode=true&characterEncoding=utf8
spring.primary.druid.driverClassName=com.mysql.jdbc.Driver
spring.primary.druid.username=root
spring.primary.druid.password=root
spring.secondary.druid.url=jdbc:mysql://localhost:3306/database1?useUnicode=true&characterEncoding=utf8
spring.secondary.druid.driverClassName=com.mysql.jdbc.Driver
spring.secondary.druid.username=root
spring.secondary.druid.password=root
- DynamicDataSource继承spring的AbstractRoutingDataSouce类用来切换数据源，在整合mybatis的框架最终通过determineCurrentLookupKey方法决定当前的执行计划选择哪一个
package com.tao.study.dynamic;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import javax.sql.DataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
import org.springframework.stereotype.Component;
@Component
public class DynamicDataSouce extends AbstractRoutingDataSource {
@Autowired
@Qualifier("readDataSouce")
private DataSource readDataSource;
@Autowired
@Qualifier("writeDataSouce")
private DataSource writeDataSource;
@Override
public void afterPropertiesSet() {
if(writeDataSource==null) {
throw new IllegalArgumentException("write data souce can not be empty");
}
setDefaultTargetDataSource(writeDataSource);
Map<Object,Object> targetDataSources = new ConcurrentHashMap<Object, Object>();
targetDataSources.put(DynamicDataSouceType.WRITE, writeDataSource);
if(readDataSource!=null) {
targetDataSources.put(DynamicDataSouceType.READ, readDataSource);
}
setTargetDataSources(targetDataSources);
super.afterPropertiesSet();
}
@Override
protected Object determineCurrentLookupKey() {
DynamicDataSouceType type = DynamicDataSouceHolder.getDataSouceType();
if(type==null) {
return DynamicDataSouceType.WRITE;
}
return type;
}
}
- DynamicDataSouceHolder类用来存储需要切换的数据源类型，使用ThreadLocal线程本地存储确保安全性
package com.tao.study.dynamic;
public class DynamicDataSouceHolder {
public final static ThreadLocal<DynamicDataSouceType> currentDynamicDataSouceType = new ThreadLocal<DynamicDataSouceType>();
public static void putDataSouceType(DynamicDataSouceType type) {
currentDynamicDataSouceType.set(type);
}
public static DynamicDataSouceType getDataSouceType() {
return currentDynamicDataSouceType.get();
}
}
- DynamicDataSouceType枚举定义多个数据源类型
package com.tao.study.dynamic;
public enum DynamicDataSouceType {
READ,WRITE
}
- DynamicPlugin类实现mybatis的Interceptor的接口，在执行操作数据库的业务流程中对Query,Update等类型进行处理，可以根据业务需求选择相应的数据源，实现多个数据源，读写分离
package com.tao.study.dynamic;
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.SqlCommandType;
import org.apache.ibatis.plugin.Interceptor;
import org.apache.ibatis.plugin.Intercepts;
import org.apache.ibatis.plugin.Invocation;
import org.apache.ibatis.plugin.Signature;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import org.springframework.stereotype.Component;
@Component
@Intercepts({
@Signature(
type= Executor.class,
method = "update",
args = {MappedStatement.class,Object.class}),
@Signature(
type= Executor.class,
method = "query",
args = {MappedStatement.class,Object.class, RowBounds.class, ResultHandler.class})
})
public class DynamicPlugin implements Interceptor {
public Object intercept(Invocation invocation) throws Throwable {
Object[] objs = invocation.getArgs();
MappedStatement ms = (MappedStatement) objs[0];
DynamicDataSouceType type = null;
// 如果执行select语句使用READ数据源, 其它使用WRITE数据源
if(ms.getSqlCommandType().equals(SqlCommandType.SELECT)){
type = DynamicDataSouceType.READ;
}else {
type = DynamicDataSouceType.WRITE;
}
DynamicDataSouceHolder.putDataSouceType(type);
return invocation.proceed();
}
}
- MybatisConfig配置SqlSessionFactory注入Plugins、DataSource
package com.tao.study.dynamic;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.boot.autoconfigure.SpringBootVFS;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class MybatisConfig {
@Autowired
private DynamicDataSouce dynamicDataSouce;
@Autowired
private DynamicPlugin dynamicPlugin;
@Bean
public SqlSessionFactory sqlSessionFactory() throws Exception {
System.out.println("SqlSessinFactory");
SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
factoryBean.setDataSource(dynamicDataSouce);
factoryBean.setPlugins(dynamicPlugin);
factoryBean.setVfs(SpringBootVFS.class); // Sets the SpringBootVFS class into SqlSessionFactoryBean
// ...
return factoryBean.getObject();
}
}
