Detailed Explanation of Dynamic Refresh Configuration for Spring boot Application

Directory 1. Dependency 2. Configuration Exposes Interface 3. @ RefreshScope4. Start Service 5. Modify Configuration 6. Get Configuration Values 7. Refresh Configuration to Retrieve Summary

I wrote an article "Spring Cloud Bus to realize configuration real-time update", which uses configuration center to manage configuration and spring cloud bus to realize real-time notification. For simple SpringBoot applications, dynamic refresh configuration can be realized without using configuration center.

Reference://www.ofstack.com/article/222381. htm

The article uses springboot version: 2.0. 4. RELEASE springcloud version Finchley. SR1

1. Dependence

The following three dependencies need to be introduced:

compile('org.springframework.cloud:spring-cloud-starter-config')
compile('org.springframework.boot:spring-boot-starter-actuator')
compile('org.springframework.boot:spring-boot-starter-web')

(1) spring-cloud-starter-config for refresh configuration

(2) spring-boot-starter-actuator is an interface to expose the modification/refresh configuration

(3) spring-boot-starter-web is an interface for accessing exposed modification/refresh configurations

2. Configure the exposed interface

application.properties

# Use port 9999
server.port=9999
# Expose interface 
management.endpoints.web.exposure.include=env,refresh

(1) env interface, which can obtain configuration (GET) or modify configuration (POST)

(2) refresh interface, which can refresh the configuration (POST), so that value annotated by @ RefreshScope can be re-injected.

3. @RefreshScope

Add @ RefreshScope annotations where you need to refresh the configuration in real time

Step 4 Start the service

Step 5 Modify the configuration

Visit localhost: 9999/actuator/env (GET) to get the configuration at this time

Visit localhost: 9999/actuator/env (POST)

{
    "name":"somekey",
    "value":"newvalue"
}

As above, the value corresponding to somekey in the configuration can be changed to newvalue

6. Get configuration values

Get the injected configuration value directly without calling the refresh interface, and find that it is still the old value

7. Refresh configuration to retrieve

Access localhost: 9999/actuator/refresh (POST) to refresh configuration

Retrieve the injected configuration value and find that it is a new value

Summarize

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