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How to use Nacos as the configuration center, I believe that many inexperienced people do not know what to do. Therefore, this paper summarizes the causes and solutions of the problem. Through this article, I hope you can solve this problem.

We have learned how to use Nacos to register and discover services. At the same time, it also introduces several different coding styles of service consumption that we can use in Spring Cloud. Next, let's take a look at another important capability of Nacos: configuration management.

Brief introduction

Nacos not only implements the registration discovery of services, but also integrates the configuration center functions. Through the configuration management function of Nacos, we can centralize and store all the configurations in the entire architecture in Nacos. The benefits of this are also mentioned in the introduction to Spring Cloud Config in previous tutorials, mainly on the following points:

Separate multi-environment configuration, more flexible management rights and higher security

The packaging of the application is more pure, so that it can be packaged once and run in multiple places.

Nacos's configuration management model is similar to Taobao's open source configuration center Diamond. At the basic level, configuration content is located through DataId and Group. In addition, many other management functions are added.

Getting started

Let's use a simple example to show how to create configuration content in Nacos and how to load Nacos configuration information in a Spring Cloud application.

Create configuration

Step 1: go to the control page of Nacos. On the configuration list function page, click the "+" button in the upper right corner to enter the "New configuration" page, as shown in the following figure:

Where:

Data ID: enter alibaba-nacos-config-client.properties

Group: do not modify, use the default value DEFAULT_GROUP

Configuration format: select Properties

Configuration content: apply the configuration content to be loaded. Here is just an example to make a simple configuration, such as didispace.title=spring-cloud-alibaba-learning

Create an application

Step 1: create a Spring Boot application that can be named: alibaba-nacos-config-client.

Step 2: edit the pom.xml and add the necessary dependency configuration, such as:

Org.springframework.boot spring-boot-starter-parent 2.0.5.RELEASE org.springframework.cloud spring-cloud-dependencies Finchley.SR1 pom import org.springframework.cloud spring-cloud-alibaba-dependencies 0.2.2.RELEASE pom Import org.springframework.boot spring-boot-starter-web org.springframework.cloud spring-cloud-starter-alibaba-nacos-config org.projectlombok lombok 1.18.2 true

The above contents are mainly divided into three parts:

Parent: defines the version of spring boot

The version of dependencyManagement:spring cloud and the version of spring cloud alibaba. Since spring cloud alibaba has not been included in the main version management of spring cloud, you need to join it yourself.

Dependencies: dependent content to be used by the current application. Here is a new configuration client module of Nacos: spring-cloud-starter-alibaba-nacos-config. Since a version has been introduced in dependencyManagement, there is no need to specify a specific version here.

As you can see, there is no nacos service discovery module in this example, so the two contents can be used independently.

Step 3: create the application main class and implement a HTTP interface:

@ SpringBootApplicationpublic class TestApplication {public static void main (String [] args) {SpringApplication.run (TestApplication.class, args); @ Slf4j @ RestController @ RefreshScope static class TestController {@ Value ("${didispace.title:}") private String title; @ GetMapping ("/ test") public String hello () {return title;}

The content is very simple. @ SpringBootApplication is defined as a SpringBoot application, and a Controller is also defined, in which the configuration with key as didispace.title (empty string by default) is injected through the @ Value annotation. This configuration will be returned through the / test interface. Later, we will use this API to verify the load configured in Nacos. In addition, there is an important note @ RefreshScope, which is mainly used to enable the configuration content under this class to support dynamic refresh, that is, when our application is launched and the configuration content in Nacos is modified, it will take effect immediately.

Step 4: create a profile bootstrap.properties and configure the service name and Nacos address

Spring.application.name=alibaba-nacos-config-clientserver.port=8001spring.cloud.nacos.config.server-addr=127.0.0.1:8848

Note: bootstrap.properties must be used here. At the same time, the spring.application.name value must match the configuration Data Id created in the previous stage Nacos (except for the .properties or .yaml suffixes).

Step 5: start the application created above.

At startup, we can see the log information similar to the above, which will output the dataId and group for the application to get the configuration from the Nacos. If, after startup, you find that the configuration information is not available, you can start here to see if the configuration is loaded correctly.

Step 6: verify configuration acquisition and verify dynamic refresh

Use tools such as curl or postman to access the API: localhost:8001/test. If everything is normal, you will return the spring-cloud-alibaba-learning configured in Nacos. Then, through the Nacos page, modify the content, click publish, and then visit the interface, you can see that the returned result has changed.

After reading the above, have you mastered how to use Nacos as the configuration center? If you want to learn more skills or want to know more about it, you are welcome to follow the industry information channel, thank you for reading!

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