dubbo入门及面试必问

public interface UserService {
    public String getUser(String userName);
}

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--上面封装的公用包-->
        <dependency>
            <groupId>com.yangle</groupId>
            <artifactId>common</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-spring-boot-starter</artifactId>
            <version>${dubbo.version}</version>
        </dependency>
        <!-- 使用zk 做注册中心，Dubbo 需要的依赖 -->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-dependencies-zookeeper</artifactId>
            <version>${dubbo.version}</version>
            <type>pom</type>
            <exclusions>
                <exclusion>
                    <groupId>org.slf4j</groupId>
                    <artifactId>slf4j-log4j12</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

dubbo.application.name=provider-service
dubbo.registry.address=zookeeper://127.0.0.1:2181
dubbo.registry.protocol=zookeeper
dubbo.protocol.name=dubbo
dubbo.protocol.port=20880
server.port=8083

@EnableDubbo
@SpringBootApplication
public class ProviderApplication {

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

@Service  //这里的service注意不是spring提供的，而是dubbo的service注解
@Component
public class UserServiceImpl implements UserService {
    @Override
    public String getUser(String userName) {
        return String.format("欢迎你:%s", userName);
    }
}

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>com.yangle</groupId>
            <artifactId>common</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-spring-boot-starter</artifactId>
            <version>${dubbo.version}</version>
        </dependency>
        <!-- 使用zk 做注册中心，Dubbo 需要的依赖 -->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-dependencies-zookeeper</artifactId>
            <version>${dubbo.version}</version>
            <type>pom</type>
            <exclusions>
                <exclusion>
                    <groupId>org.slf4j</groupId>
                    <artifactId>slf4j-log4j12</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

server.port=8082
dubbo.application.name=consumer-service
dubbo.registry.address=zookeeper://127.0.0.1:2181

@EnableDubbo //dubbo注解
@SpringBootApplication
public class ConsumerApplication {

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

}

@RestController
public class HomeRestController {
    @Reference //使用dubbo的reference注解引入dubbo服务
    private UserService userService;
    @RequestMapping("/{userName}")
    public String getUser(@PathVariable String userName){
        return userService.getUser(userName);
    }
}

dubbo.consumer.check = false
<!--消费者启动时不检查服务提供者是否存在-->
dubbo.registry.check=false
<!--注册中心启动时是否检查-->

<!--服务注解配置-->
@Reference(timeout = 1000)
<!--消费者全局配置-->
dubbo.consumer.timeout=5000

<!--不包括第一次调用-->
<!--全局配置-->
dubbo.consumer.retries=3
dubbo.provider.retries=3
<!--服务级别配置-->
@Reference(timeout = 5000,retries = 3)
private UserService userService;

<!--服务提供方-->
@Service(version = "1")
<!--服务消费方-->
<!--version 为* 代表随机调用任何一个服务提供者-->
@Reference(timeout = 5000,retries = 3,version = "1")
private UserService userService;

<!--消费方的注解上添加存根的全类名-->
@Reference(timeout = 5000,retries = 3,version = "1",stub = "com.yangle.consumer.UserServieStub")
private UserService userService;
<!--存根需要继承服务接口，并且提供服务有参构造器-->
public class UserServieStub implements UserService {
    private UserService userService;

    public UserServieStub(UserService userService) {
        this.userService = userService;
    }

    @Override
    public String getUser(String userName) {
        System.out.println("进入存根");
        return userService.getUser(userName);
    }
}

消费者上面加上注解 添加dubbo服务的url
@Reference(url = "127.0.0.1:20882")

@Reference(loadbalance = "负载均衡机制名称")
private UserService userService;
@Service(loadbalance = "负载均衡机制名称")
<!--名称可以为 consistenthash、leastactive、roundrobin、random-->

dubbo.consumer.cluster= 
dubbo.provider.cluster=

@Service(cluster = "")
@Reference(cluster = "")
private UserService userService;