// 方案二的示例代碼
// 定義讀寫分離的注解
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ReadWriteDataSource {
    DataSourceType value() default DataSourceType.READ;
}
// 創(chuàng)建動態(tài)代理類
public class ReadWriteDataSourceInterceptor implements MethodInterceptor {
    @Override
    public Object invoke(MethodInvocation invocation) throws Throwable {
        Method method = invocation.getMethod();
        ReadWriteDataSource annotation = method.getAnnotation(ReadWriteDataSource.class);
        if (annotation != null) {
            DataSourceType dataSourceType = annotation.value();
            if (dataSourceType == DataSourceType.READ) {
                // 切換到讀數(shù)據(jù)源
                DynamicDataSource.setDataSource(DataSourceType.READ);
            } else {
                // 切換到寫數(shù)據(jù)源
                DynamicDataSource.setDataSource(DataSourceType.WRITE);
            }
        }
        try {
            return invocation.proceed();
        } finally {
            // 恢復默認數(shù)據(jù)源
            DynamicDataSource.resetDataSource();
        }
    }
}
// 配置AOP切面
@Configuration
public class AopConfig {
    @Bean
    public ReadWriteDataSourceInterceptor readWriteDataSourceInterceptor() {
        return new ReadWriteDataSourceInterceptor();
    }
    @Bean
    public Advisor readWriteDataSourceAdvisor(ReadWriteDataSourceInterceptor interceptor) {
        AspectJExpressionPointcut pointcut = new AspectJExpressionPointcut();
        pointcut.setExpression("@annotation(com.example.ReadWriteDataSource)");
        return new DefaultPointcutAdvisor(pointcut, interceptor);
    }
}
// 在業(yè)務代碼中使用注解
@Service
public class UserService {
    @Autowired
    private UserDao userDao;
    @ReadWriteDataSource(DataSourceType.READ)
    public User getUserById(Long
 userId) {
        return userDao.getById(userId);
    }
    @ReadWriteDataSource(DataSourceType.WRITE)
    public void updateUser(User user) {
        userDao.update(user);
    }
}