springcloud (4) is called between the common micro-services

table of Contents

Called between the commonly used micro-services

RPC:

Rest(Http):

ribbon merchandise orders call service

Custom load balancing strategy:

feign way to achieve inter-call service

Feign way call between the core and the source code interpretation service ribbon, feign selection

Called between the commonly used micro-services

RPC:

Remote procedure calls, such as calling a local service (method) call the server the same service

It supports synchronous, asynchronous calls

Establishing a TCP connection between the client and the server, you can set up a time, but also a multiplex link (a connection time-consuming) and more large companies can use multiple RPC calls

PRC small packets

protobuf

thrift

rpc: codec, serialization, links, packet loss, protocol (large costs)

Rest(Http):

http request, support for multiple protocols and functions

Facilitate the development of low cost

http packets large

java development: HttpClient, URLConnection

spring cloud temporarily in this way

ribbon merchandise orders call service

1. Create a project order_service

2, the development of a pseudo-single Interface

3, using a ribbon. (Similar httpClient, URLConnection) packing more stuff

Start class adds comment

@Bean

@LoadBalanced

Template Residual public rest template () {

return new RestTemplate();

}

4, call by name merchandise, Getting product details

Get product-service from the list of eureka in the (registered in the name of the yml)

Ribbon source code analysis

Analysis @LoadBalanced

1) First, get a list from the registry provider

2) by selecting a certain strategy wherein a node

3) back to the calling restTemplate

Want to find the service name

Get a list of product-service

(Default policy)

serviceId（product-service)

Custom load balancing strategy:

http://cloud.spring.io/spring-cloud-static/Finchley.RELEASE/single/spring-cloud.html#_customizing_the_ribbon_client_by_setting_properties

In the configuration file yml inside, custom load balancing strategy

# Custom load balancing strategy

product-service: (registered service name're looking for call center services strategy which can have many services each service has a corresponding strategy)

ribbon:

NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule

Strategies:

1, the same as if each machine configuration, it is recommended not to modify the policy (recommended)

2, if the strong part of the machine configuration, you can instead WeightedResponseTimeRule (see IRule implementation class)

feign way to achieve inter-call service

Renovation project electricity supplier orders for service calls Goods Services get product information

Feign: pseudo-RPC client (or nature with http)

官方文档: https://cloud.spring.io/spring-cloud-openfeign/

1、使用feign步骤讲解（新旧版本依赖名称不一样）

加入依赖

  <dependency>

       <groupId>org.springframework.cloud</groupId>

       <artifactId>spring-cloud-starter-openfeign</artifactId>

  </dependency>

启动类增加@EnableFeignClients

增加一个接口并@FeignClient(name="product-service")

官文

@SpringBootApplication
@EnableFeignClients
public class WebApplication {

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

	@FeignClient("name")
	static interface NameService {
		@RequestMapping("/")
		public String getName();
	}
}

2、编码实战

@FeignClient(name="product-service")
public interface ProductClients {
    @GetMapping("/api/v1/product/find")
    String findById(@RequestParam(value = "id")int id);

}

   @Resource
    ProductClients productClients;

    @Override
    public ProductOrder save(int userId, int productId) {
        //Object object = restTemplate.getForObject("http://product-service/api/v1/product/find?id=" + productId, Object.class);
        // System.out.println(object);
        //  Map<String,Object> productMap = restTemplate.getForObject("http://product-service/api/v1/product/find?id=" + productId, Map.class);
        String response = productClients.findById(productId);
        JsonNode jsonNode = JsonUtil.str2JsonNode(response);


        ProductOrder productOrder = new ProductOrder();
        productOrder.setCreateTime(new Date());
        productOrder.setTradeNo(UUID.randomUUID().toString());
        productOrder.setUserId(userId);productOrder.setPrice(Integer.parseInt(jsonNode.get("price").toString()) );
        productOrder.setProductName(jsonNode.get("name").toString());

        return productOrder;
    }

3、注意点：

1、路径 (要和调用方product-service的路由保持一致)

@FeignClient(name="product-service") 要和保持一致

2、Http方法必须对应

3、使用requestBody，应该使用@PostMapping

4、多个参数的时候，通过@RequestParam（"id") int id)方式调用

"id"要和（int id）保持一致

Feign核心源码解读和服务间的调用方式ribbon、feign选择

1、ribbon和feign两个的区别和选择

选择feign

默认集成了ribbon

写起来更加思路清晰和方便

采用注解方式进行配置，配置熔断等方式方便

2、超时配置

默认options readtimeout是60，但是由于hystrix默认是1秒超时

#修改调用超时时间

feign:

client:

config:

default:

connectTimeout: 2000

readTimeout: 2000

模拟接口响应慢，线程睡眠新的方式

try {

TimeUnit.SECONDS.sleep(1);

} catch (InterruptedException e) {

e.printStackTrace();

}