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springboot+mybatis实现动态切换数据源

2018-10-28 01:15 1231 查看

前几天有个需求,需要使用不同的数据源,例如某业务要用A数据源,另一个业务要用B数据源。我上网收集了一些资料整合了一下,虽然最后这个需求不了了之了,但是多数据源动态切换还是蛮好用的,所以记录一下,或许以后有用呢?或者自己感兴趣又想玩呢!

1.加个依赖

<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
       <version>1.3.1</version> </dependency>

2.application.properties配置文件

#主从数据库
master.db.driverClassName=com.mysql.jdbc.Driver
master.db.url=jdbc:mysql://localhost:3306/cbd?characterEncoding=UTF-8&useUnicode=true&useSSL=false
master.db.username=root
master.db.password=admin
slave.db.driverClassName=com.mysql.jdbc.Driver
slave.db.url=jdbc:mysql://localhost:3306/cbd_test?characterEncoding=UTF-8&useUnicode=true&useSSL=false
slave.db.username=root
slave.db.password=admin

mybatis.config-location= classpath:config/mybatis-config.xml
mybatis.mapper-locations=classpath:mapper/**/*.xml

 

3.禁用springboot默认加载数据源配置

@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
public class Application {

public static void main(String[] args) throws Exception {
SpringApplication.run(Application.class, args);
}
}

4.数据源配置类

/**
* 主数据源
*/
@Configuration
@ConfigurationProperties(prefix = "master.db")
public class MasterDataSourceConfig {
private String url;
private String username;
private String password;
private String driverClassName;
}
/**
* 从数据源配置
*/
@Configuration
@ConfigurationProperties(prefix = "slave.db")
public class SlaveDataSourceConfig {
private String url;
private String username;
private String password;
private String driverClassName;
}
/**
* 数据源配置类
*/
@Configuration
public class DataSourceComponent {

@Resource
private MasterDataSourceConfig masterDataSourceConfig;

@Resource
private SlaveDataSourceConfig slaveDataSourceConfig;

@Bean(name = "master")
public DataSource masterDataSource() {
DataSource dataSource = new DataSource();
dataSource.setUrl(masterDataSourceConfig.getUrl());
dataSource.setUsername(masterDataSourceConfig.getUsername());
dataSource.setPassword(masterDataSourceConfig.getPassword());
dataSource.setDriverClassName(masterDataSourceConfig.getDriverClassName());
return dataSource;
}

@Bean(name = "slave")
public DataSource slaveDataSource() {
DataSource dataSource = new DataSource();
dataSource.setUrl(slaveDataSourceConfig.getUrl());
dataSource.setUsername(slaveDataSourceConfig.getUsername());
dataSource.setPassword(slaveDataSourceConfig.getPassword());
dataSource.setDriverClassName(slaveDataSourceConfig.getDriverClassName());
return dataSource;
}

@Primary//不加这个会报错。
@Bean(name = "multiDataSource")
public MultiRouteDataSource exampleRouteDataSource() {
MultiRouteDataSource multiDataSource = new MultiRouteDataSource();
Map<Object, Object> targetDataSources = new HashMap<>();
targetDataSources.put("master", masterDataSource());
targetDataSources.put("slave", slaveDataSource());
multiDataSource.setTargetDataSources(targetDataSources);
multiDataSource.setDefaultTargetDataSource(masterDataSource());
return multiDataSource;
}
}

5.数据源上下文

/**
* 数据源上下文
*/
public class DataSourceContext {
private static final ThreadLocal<String> contextHolder = new ThreadLocal<>();

public static void setDataSource(String value) {
contextHolder.set(value);
}

public static String getDataSource() {
return contextHolder.get();
}

public static void clearDataSource() {
contextHolder.remove();
}
}

6.DataSource路由类

/*
*    重写的函数决定了最后选择的DataSource
*/
public class MultiRouteDataSource extends AbstractRoutingDataSource {

@Override
protected Object determineCurrentLookupKey() {
//通过绑定线程的数据源上下文实现多数据源的动态切换,有兴趣的可以去查阅资料或源码
return DataSourceContext.getDataSource();
}

}

 

7.使用,修改上下文中的数据源就可以切换自己想要使用的数据源了。

public UserVO findUser(String username) {
DataSourceContext.setDataSource("slave");
UserVO userVO = userMapper.findByVO(username);
System.out.println(userVO.getName()+"=====================");
return null;
}

这种是在业务中使用代码设置数据源的方式,也可以使用AOP+注解的方式实现控制,方法多多!

 

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