dubbo（7）：配置（2）

心已赠人 2022-10-15 04:46 160阅读 0赞

# 五、多版本（灰度发布） #

在 Dubbo 中为同一个服务配置多个版本。当一个接口实现，出现不兼容升级时，可以用版本号过渡，版本号不同的服务相互间不引用。（详细查看官方文档用法实例）

可以按照以下的步骤进行版本迁移：

1.  在低压力时间段，先升级一半提供者为新版本
2.  再将所有消费者升级为新版本
3.  然后将剩下的一半提供者升级为新版本

把UserServiceImpl复制一份，作为新版本。

![20210523152349107.png][]

分别定义两个版本号。

package com.buba.service.impl;
    
    import com.buba.pojo.UserAddress;
    import com.buba.service.UserService;
    import org.apache.dubbo.config.annotation.DubboService;
    import org.springframework.stereotype.Service;
    
    import java.util.Arrays;
    import java.util.List;
    
    @DubboService(version = "1.0.0") // 暴露服务
    @Service
    public class UserServiceImpl implements UserService {
        @Override
        public List<UserAddress> getUserAddressList(String userId) {
            UserAddress userAddress1 = new UserAddress(1, "北京", "1", "张三", "17611112222", "是");
            UserAddress userAddress2 = new UserAddress(2, "天津", "1", "张三", "17611112222", "是");
            return Arrays.asList(userAddress1, userAddress2);
        }
    }

package com.buba.service.impl;
    
    import com.buba.pojo.UserAddress;
    import com.buba.service.UserService;
    import org.apache.dubbo.config.annotation.DubboService;
    import org.springframework.stereotype.Service;
    
    import java.util.Arrays;
    import java.util.List;
    
    @DubboService(version = "2.0.0") // 暴露服务
    @Service
    public class UserServiceImpl2 implements UserService {
        @Override
        public List<UserAddress> getUserAddressList(String userId) {
            UserAddress userAddress1 = new UserAddress(1, "北京", "1", "张三", "17611112222", "是");
            UserAddress userAddress2 = new UserAddress(2, "天津", "1", "张三", "17611112222", "是");
            return Arrays.asList(userAddress1, userAddress2);
        }
    }

这样在消费方就可以指定使用哪个版本的服务。

package com.buba.service.impl;
    
    import com.buba.pojo.UserAddress;
    import com.buba.service.OrderService;
    import com.buba.service.UserService;
    import org.apache.dubbo.config.annotation.DubboReference;
    import org.springframework.stereotype.Service;
    
    import java.util.List;
    
    @Service
    public class OrderServiceImpl implements OrderService {
        @DubboReference(retries = 3,version = "1.0.0") // 去dubbo注册中心中寻找
        private UserService userService;
    
        @Override
        public List<UserAddress> initOrder(String userId) {
            return userService.getUserAddressList("1");
        }
    
    }

# 六、本地存根 #

在 Dubbo 中利用本地存根在客户端执行部分逻辑。远程服务后，客户端通常只剩下接口，而实现全在服务器端，但提供方有些时候想在客户端也执行部分逻辑，比如：做 ThreadLocal 缓存，提前验证参数，调用失败后伪造容错数据等等，此时就需要在 API 中带上 Stub，客户端生成 Proxy 实例，会把 Proxy 通过构造函数传给 Stub [1][]，然后把 Stub 暴露给用户，Stub 可以决定要不要去调 Proxy。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMjk4MzUx_size_16_color_FFFFFF_t_70][]

在订单客户端创建一个用户实现（本地存根）用于验证。

![20210523153530502.png][]

编写本地存根实现。

package com.buba.service.impl;
    
    import com.buba.pojo.UserAddress;
    import com.buba.service.UserService;
    
    import java.util.List;
    
    public class UserServiceStub implements UserService {
    
        private final UserService userService;
    
        /**
         * 传入UserService远程的代理对象
         *
         * @param userService
         */
        public UserServiceStub(UserService userService) {
            this.userService = userService;
        }
    
        @Override
        public List<UserAddress> getUserAddressList(String userId) {
            if (!"".equals(userId)) {
               return userService.getUserAddressList(userId);
            }
            return null;
        }
    }

配置本地存根。

package com.buba.service.impl;
    
    import com.buba.pojo.UserAddress;
    import com.buba.service.OrderService;
    import com.buba.service.UserService;
    import org.apache.dubbo.config.annotation.DubboReference;
    import org.springframework.stereotype.Service;
    
    import java.util.List;
    
    @Service
    public class OrderServiceImpl implements OrderService {
        @DubboReference(retries = 3,version = "1.0.0",stub = "com.buba.service.impl.UserServiceStub") // 去dubbo注册中心中寻找
        private UserService userService;
    
        @Override
        public List<UserAddress> initOrder(String userId) {
            return userService.getUserAddressList("1");
        }
    
    }

# 七。dubbo服务方法级配置 #

导入dubbo-spring-boot-starter包，在application.yml中配置。使用@DubboService发布服务，@DubboReference引用服务，@EnableDubbo开启dubbo注解扫描。通过@Method可以将dubbo精确到方法级。

package com.buba.service.impl;
    
    import com.buba.pojo.UserAddress;
    import com.buba.service.UserService;
    import org.apache.dubbo.config.annotation.DubboService;
    import org.apache.dubbo.config.annotation.Method;
    import org.springframework.stereotype.Service;
    
    import java.util.Arrays;
    import java.util.List;
    
    @DubboService(version = "1.0.0", methods = {@Method(name = "getUserAddressList", timeout = 250, retries = 0)}) // 暴露服务
    @Service
    public class UserServiceImpl implements UserService {
    
        @Override
        public List<UserAddress> getUserAddressList(String userId) {
            UserAddress userAddress1 = new UserAddress(1, "北京", "1", "张三", "17611112222", "是");
            UserAddress userAddress2 = new UserAddress(2, "天津", "1", "张三", "17611112222", "是");
            return Arrays.asList(userAddress1, userAddress2);
        }
    }

可以在启动类中通过注解加载dubbo配置（xml）文件方式。

package com.buba;
    
    import org.apache.dubbo.config.spring.context.annotation.EnableDubbo;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.ImportResource;
    
    // @EnableDubbo // 开启基于注解的Dubbo功能
    @ImportResource(locations = "classpath:consumer.xml")
    @SpringBootApplication
    public class OrderServiceConsumer_8802 {
        public static void main(String[] args) {
            SpringApplication.run(OrderServiceConsumer_8802.class, args);
        }
    }

[20210523152349107.png]: /images/20221014/b561d4fbf64d4c21b1bde5e034407722.png
[1]: https://dubbo.apache.org/zh/docs/v2.7/user/examples/local-stub/#fn:1
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMjk4MzUx_size_16_color_FFFFFF_t_70]: /images/20221014/d2a315e84bfc4c8580e19343159c6508.png
[20210523153530502.png]: /images/20221014/c45ac31469734b6ca5e27b60b8e16c05.png