spring boot + mybatis实现动态切换数据源实例代码

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

#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. 
mybatis.mapper-locations=classpath:mapper/**/*. 

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

/**
 * 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< ,  > targetDataSources = new HashMap<>();
  targetDataSources.put(\"master\", masterDataSource());
  targetDataSources.put(\"slave\", slaveDataSource());
  multiDataSource.setTargetDataSources(targetDataSources);
  multiDataSource.setDefaultTargetDataSource(masterDataSource());
  return multiDataSource;
 }
}

/**
 * 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();
 }
}

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

 @Override
 protected   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();
 }

}

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