Calling services between Spring Cloud microservices-Spring Cloud microservices use Feign to call another service and the use of Feign

Introduction to Feign

There are many service instances of the microservice architecture. How to call between services and services, Spring Cloud provides a solution: Feign the pretender.

Feign is a component of Spring Cloud and a WebService client, used for transfer between services.
To learn more about Feign, please check: https://blog.csdn.net/wo18237095579/article/details/83343915

Create two services

Create two projects and two services, configure the registry, and then start the two services, you can see two service names in the registry you configured: my two services, Daily-server and Task-Server. as follows:

Methods of calling between Feign microservices

I am here to call Task-server through Daily-server. First, configure Daily-server. The details are as follows:

1. Add dependency

1.1: Add Feign's dependency

		<dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
            <scope>provided</scope>
        </dependency>

1.2 If the spring boot project integrates spring cloud here, that is, when there is a spring boot dependency in your project, you need to add the spring cloud dependency as:

			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-dependencies</artifactId>
				<version>Hoxton.SR1</version>
				<type>pom</type>
				<scope>import</scope>
			</dependency>

1.3 When you directly create a spring cloud project, you do not need the steps in 1.2 above, and directly add spring cloud dependencies:

		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-hystrix</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-hystrix-dashboard</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-feign</artifactId>
		</dependency>

2. Add annotations to the service startup class

@EnableFeignClients

As follows:
3. Create an interface to reference the TaskServer interface

package ...app.feign;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;

@FeignClient("task-server")
public interface TaskServerFeign {
    
    
    @GetMapping("/task/test")
    String getTest();
}

Here @FeignClient("task-server") where task-server is the name of your other service
@GetMapping("/task/test") The address of the interface in another service
String getTest(); The interface of another service name.

4. Create a test interface and call another service's interface

import 。。。.feign.TaskServerFeign;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@Api(tags = {
    
    "Feign测试"})
public class FeignTest {
    
    
    @Autowired
    private TaskServerFeign taskServerFeign;

    @GetMapping("/task/test1")
    public void getTest() {
    
    
        String test = taskServerFeign.getTest();
        System.out.println(test);
        System.out.println("----------this is daily_Server_test");
    }
}

@Api(tags = {"Feign test"}) This annotation is only used locally for swagger testing. You can also use other methods to call this interface for testing, such as postman

@Autowired
private TaskServerFeign taskServerFeign; Inject the interface that calls task-server in the third step.

5. Create the called interface in task-server

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class FeignTest {
    
    
    @GetMapping("/task/test")
    public String getTest() {
    
    
        System.out.println("----------this is task_Server_test");
        return "this is task_Server_test";
    }
}

The next step is to run and test. The local test is as follows:
here is the test tool for testing,

here is the Daily-server and

this is the Task-servrer.

The result is obvious. Novice Xiaobai welcomes your comments at any time. 0. 0