Introduction to Nacos as a registry and configuration center - realize remote call, dynamically obtain configuration files and database configuration information

download nacos To local , You can double-click startup.cmd To start the , The default is 8848 port

As a registry

First, import dependency

         <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-alibaba-nacos-discovery</artifactId>
            <version>2.1.0.RELEASE</version>
        </dependency>

Configure in profile Nacos Server Address

#  apply name 
spring.application.name=nacos1
spring.cloud.nacos.discovery.server-addr=127.0.0.1:8848

Add comments to the main class , Register your own services

@EnableDiscoveryClient  // Open service registration discovery

Start at this time nacos after , You can register the project after starting the project

 

The remote invocation

Feign It's a declarative one Http client , Provides http The request template , By writing simple interfaces and inserting annotations , You can define http Request parameters 、 Format 、 Address and other information .

Feign Integrated Ribbon( Load balancing ) and Hystrix( Service failure ), We can eliminate the need to explicitly use these two components

Remote call usage ：

1. Add dependencies to the project , introduce feign

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
            <version>2.2.1.RELEASE</version>
        </dependency>

2. Writing interface , Write interface tell springcloud Need to call remote service

@FeignClient("nacos1")  // Corresponding service name 
public interface feigndemo {
    // Find the method you want to call other services and copy it 
    @RequestMapping("/lzq/testfeign") // The path should be written completely 
    public R testfeign();
}

At this point, when the current method calls the interface , It will automatically find the corresponding service in the registry and access the corresponding interface

You also need to add comments to the main class @EnableFeignClients, Open the remote call of the client

At the same time, you can specify the full class name of the corresponding interface package , As long as the service starts, it will automatically scan

@EnableFeignClients(basePackages = "com.lzq.feign")

Configuration center

 

First, introduce dependency to establish connections

       <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
            <version>2.1.0.RELEASE</version>
        </dependency>

Create... In the project bootstrap.properties file , This document will take precedence over application.properties File loading

Configure the service name and address

spring.application.name=nacos1
spring.cloud.nacos.discovery.server-addr=127.0.0.1:8848

Modify profile dynamically

land nacos website , Configure the information that needs to be dynamically modified in the configuration list

Data ID Name the service +.properties, Profile selection properties, After writing the configuration, click publish

Add comments to the corresponding method @RefreshScope annotation

@RefreshScope
@RestController
public class Demo {

    @Value("${shop.zhekou}")
    private String zk;
}

At this point, get the corresponding value through the code , You can dynamically modify the corresponding configuration value

details ： Namespace 、 config set 、 To configure ID、 Configure grouping

Namespace : Default public, The main function is to configure isolation ,( You can test through multiple namespaces 、 Generating environment ), It can be done by bootstrap.properties Namespace specified in

spring.cloud.nacos.config.namespace=xxxxx

 

Configure grouping ： The same namespace can be configured differently according to different activities , Specify the corresponding group

spring.cloud.nacos.config.group=dev

Manage data sources

spring.cloud.nacos.config.ext-config[0].data-id=datasource.yml
spring.cloud.nacos.config.ext-config[0].group=dev
spring.cloud.nacos.config.ext-config[0].refresh=true  // Dynamic refresh 

spring.cloud.nacos.config.ext-config[1].data-id=mybatis.yml
spring.cloud.nacos.config.ext-config[1].group=dev
spring.cloud.nacos.config.ext-config[1].refresh=true