浅谈利用Spring的AbstractRoutingDataSource解决多数据源的问题

public class DynamicDataSourceextends AbstractRoutingDataSource{

  @Override
  protectedObjectdetermineCurrentLookupKey(){
    String dataSourceName = DynamicDataSourceContextHolder.getDataSourceName();
    return dataSourceName;
  }
}

/**
 * 动态数据源上下文
 */
public class DynamicDataSourceContextHolder{

  private static final ThreadLocal<String> contextHolder = new ThreadLocal<>();
  public static List<String> dataSourceNames = new ArrayList<>();

  public static void setDataSourceName(String name){
    contextHolder.set(name);
  }

  public staticStringgetDataSourceName(){
    return contextHolder.get();
  }

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

  public static boolean containsDataSource(String dataSourceName){
    return dataSourceNames.contains(dataSourceName);
  }

}

@Configuration
public class DataSourceConfig{

  @Bean(name = "primaryDataSource")
  @ConfigurationProperties(prefix = "spring.datasource.primary")
  @Primary
  publicDataSourceprimaryDataSource(){
    return DataSourceBuilder.create().build();
  }

  @Bean(name = "secondaryDataSource")
  @ConfigurationProperties(prefix = "spring.datasource.secondary")
  publicDataSourcesecondaryDataSource(){
    return DataSourceBuilder.create().build();
  }

  @Autowired
  @Qualifier("primaryDataSource")
  private DataSource primaryDataSource;

  @Autowired
  @Qualifier("secondaryDataSource")
  private DataSource secondaryDataSource;

  @Bean
  publicDynamicDataSourcedataSource(){

    Map<Object, Object> targetDataSources = new HashMap<>();
    targetDataSources.put("primaryDataSource", primaryDataSource);
    targetDataSources.put("secondaryDataSource", secondaryDataSource);

    DynamicDataSourceContextHolder.dataSourceNames.add("primaryDataSource");
    DynamicDataSourceContextHolder.dataSourceNames.add("secondaryDataSource");

    DynamicDataSource dataSource = new DynamicDataSource();
    //设置数据源映射
    dataSource.setTargetDataSources(targetDataSources);
    //设置默认数据源，当无法映射到数据源时会使用默认数据源
    dataSource.setDefaultTargetDataSource(primaryDataSource);
    dataSource.afterPropertiesSet();

    return dataSource;
  }

}

#
spring.datasource.primary.jdbcUrl=jdbc:mysql://localhost/test1?useSSL=false
spring.datasource.primary.username=root
spring.datasource.primary.password=root
spring.datasource.primary.driver-class-name=com.mysql.jdbc.Driver
#
spring.datasource.secondary.jdbcUrl=jdbc:mysql://localhost/test2?useSSL=false
spring.datasource.secondary.username=root
spring.datasource.secondary.password=root
spring.datasource.secondary.driver-class-name=com.mysql.jdbc.Driver

/**
 * 在方法上使用，用于指定使用哪个数据源
 */
@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface TargetDataSource {

  Stringvalue();

}

@TargetDataSource(value = "primaryDataSource")
publicList<Customer>findAll(){
  //TODO
  return null;
}

@TargetDataSource(value = "secondaryDataSource")
public void addCustomer(String name, String email){

}

@Aspect
@Component
@Order(-1)// 保证该AOP在@Transactional之前执行
public class DynamicDataSourceChangeAspect{

  private static final Logger logger = LoggerFactory.getLogger(DynamicDataSourceChangeAspect.class);

  @Before("@annotation(targetDataSource)")
  public void changeDataSource(JoinPoint joinPoint, TargetDataSource targetDataSource){
    String dsName = targetDataSource.value();
    if (!DynamicDataSourceContextHolder.containsDataSource(dsName)) {
      System.err.println("数据源[{}]不存在，使用默认数据源 > {}" + targetDataSource.value() + joinPoint.getSignature());
    } else {
      DynamicDataSourceContextHolder.setDataSourceName(targetDataSource.value()); //设置到动态数据源上下文中
    }
  }

  @After("@annotation(targetDataSource)")
  public void restoreDataSource(JoinPoint point, TargetDataSource targetDataSource){
    //方法执行完毕之后，销毁当前数据源信息，进行垃圾回收。
    DynamicDataSourceContextHolder.clearDataSourceName();
  }
}