# dubbo-tutorials-parent

**Repository Path**: coder_chenjun/dubbo-tutorials-parent

## Basic Information

- **Project Name**: dubbo-tutorials-parent
- **Description**: zookeeper与dubbo的基本使用
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 1
- **Created**: 2021-12-21
- **Last Updated**: 2022-05-10

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# dubbo hello(无注册中心)

## 服务提供者

### 依赖

```xml
<dependency>
    <groupId>org.example</groupId>
    <artifactId>dubbo-api</artifactId>
    <version>1.0-SNAPSHOT</version>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
</dependency>

<dependency>
    <groupId>org.apache.dubbo</groupId>
    <artifactId>dubbo-spring-boot-starter</artifactId>
    <version>2.7.8</version>
</dependency>

```

### 提供者实现类

重点是DubboService注解

```java
@DubboService
public class ProductServiceImpl implements ProductService {
    @Override
    public String getNameById(int id) {
        System.out.println("wo bei getNameById -----");
        return id + "adfa";
    }
}
```

### 配置文件

服务名字靠spring.application.name来配置，是必须配置的，端口可以不用配置，默认是20880的

```yaml
spring:
  application:
    name: product-provider

# 下面的配置是不用注册中心的，重点是那个N/A
dubbo:
  scan:
    base-packages: com.nf.xxx.service.impl
  protocol:
    name: dubbo
#    port: 20888
  registry:
    address: N/A
```

### 启动类

```java
@SpringBootApplication
public class ProductServiceApplication {
    public static void main(String[] args) {
        SpringApplication.run(ProductServiceApplication.class, args);
    }
}
```



## 服务消费者

### 依赖

```xml
<dependency>
    <groupId>org.example</groupId>
    <artifactId>dubbo-api</artifactId>
    <version>1.0-SNAPSHOT</version>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
</dependency>

<dependency>
    <groupId>org.apache.dubbo</groupId>
    <artifactId>dubbo-spring-boot-starter</artifactId>
    <version>2.7.8</version>
</dependency>
```

### 消费者

重点是DubboReference注解的url设置

```java
@Service
public class OrderServiceImpl {
    // @Autowired
    @DubboReference(url = "dubbo://127.0.0.1:20880")
    private ProductService productService;

    public void genereateOrder() {   
        String name = productService.getNameById(1);
        System.out.println("生成订单，产品名字是：" + name);
    }
}
```

### 配置文件

```yaml
spring:
  application:
    name: order-consumer
```

### 启动类

```java
@SpringBootApplication
public class OrderConsumerApplication implements CommandLineRunner {
    public static void main(String[] args) {
        SpringApplication.run(OrderConsumerApplication.class, args);
    }

    @Autowired
    private OrderServiceImpl orderService;
    @Override
    public void run(String... args) throws Exception {
        orderService.genereateOrder();
    }
}
```

# 序列化

默认使用的是hessien2，要求类需要实现Serializable接口

```java
public class User implements Serializable {
    private int id;
    private String name;
    //省略
}
```

接口就可以直接使用，其它地方不需要改变

```java
public interface ProductService2 {
    User getUser(User user);
}
```

## kryo
```xml
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-serialization-kryo</artifactId>
            <version>2.7.8</version>
        </dependency>
```

只需要在服务端配置下面的内容即可
```xml
    <dubbo:protocol name="dubbo" serialization="kryo" />
```

可选的优化设置
```java
public class MySerializationOptimizer implements SerializationOptimizer {
    @Override
    public Collection<Class<?>> getSerializableClasses() {
        LinkedList classes = new LinkedList();
        classes.add(Aaa.class);
        return classes;
    }
}
```

```xml
<dubbo:protocol name="dubbo" serialization="kryo" optimizer="org.apache.dubbo.samples.basic.MySerializationOptimizer"/>
```

# zookeeper注册中心

采用了zookeeper作为注册中心，代码变化不大，就是提供者与消费者配置需要调整一下

## 依赖

提供者与消费者都需要与zookeeper通信，所以都需要添加下面的依赖

```xml
<dependency>
    <groupId>org.apache.dubbo</groupId>
    <artifactId>dubbo-dependencies-zookeeper</artifactId>
    <version>2.7.8</version>
    <type>pom</type>
</dependency>
```

## 提供者配置

提供者只是更改一下配置，代码不需要任何改动

```yaml
spring:
  application:
    name: product-provider
dubbo:
  scan:
    base-packages: com.nf.xxx.service.impl
  registry:
    address: zookeeper://127.0.0.1:2181
```

## 消费者配置

配置中指定注册中心的地址

```yaml
spring:
  application:
    name: order-consumer
dubbo:
  registry:
    address: zookeeper://127.0.0.1:2181
```

## 消费者代码

只需要添加注解，不需要指定url之类的东西，直接到注册中心找提供者信息

```java
@DubboReference()
private ProductService2 productService2;
```

## 负载均衡

### 单机多提供者实例

在idea中直接复制启动配置，并在启动配置环境变量下配置如下内容即可

```
dubbo.protocol.name=dubbo;dubbo.protocol.port=20881
```

如果实例运行在不同的机器上是不需要上面的操作的，直接就启动多个实例并注册到注册中心去

### 负载均衡策略

消费者默认采用的是随机策略，可以在DubboReference注解中调整

```java
@DubboReference(loadbalance = "roundrobin")
private ProductService productService;
```

loadbalance值有如下几个

- random
- roundrobin
- leastactive


# qos
```xml
  <dubbo:application name="demo-provider">
        <!-- 关闭qos -->
        <dubbo:parameter key="qos.enable" value="false"/>
        <dubbo:parameter key="qos.port" value="22223"/>
    </dubbo:application>
```

# 参考资料
- https://segmentfault.com/a/1190000019896723
- https://www.cnblogs.com/twoheads/p/10131656.html （服务路由，负载均衡，集群容错解释较清楚）
- https://blog.csdn.net/qq_22152261/article/details/80300597 (dubbo springboot整合使用与dubbo Admin的使用)
- https://www.jianshu.com/p/5f7306955482 (zookeeper的说明)