中文翻译站Quarkus - Reading properties from Spring Cloud Config Server
This guide explains how your Quarkus application can read configuration properties at runtime from the Spring Cloud Config Server.
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Prerequisites
To complete this guide, you need:
-
less than 15 minutes
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an IDE
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JDK 1.8+ installed with
JAVA_HOMEconfigured appropriately -
Apache Maven 3.6.2+
Solution
We recommend that you follow the instructions in the next sections and create the application step by step.
Stand up a Config Server
To stand up the Config Server required for this guide, please follow the instructions outlined here.
The end result of that process is a running Config Server that will provide the Hello world value for a configuration property named message when the application querying the server is named a-bootiful-client.
Creating the Maven project
First, we need a new project. Create a new project with the following command:
mvn io.quarkus:quarkus-maven-plugin:1.3.1.Final:create \
-DprojectGroupId=org.acme \
-DprojectArtifactId=spring-cloud-config-quickstart \
-DclassName="org.acme.spring.cloud.config.client.GreetingResource" \
-Dpath="/greeting" \
-Dextensions="spring-cloud-config-client"
cd spring-cloud-config-quickstartThis command generates a Maven project with a REST endpoint and imports the spring-cloud-config-client extension.
GreetingController
The Quarkus Maven plugin automatically generated a GreetingResource JAX-RS resource in the
src/main/java/org/acme/spring/cloud/config/client/GreetingResource.java file that looks like:
package org.acme.spring.spring.cloud.config.client;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
@Path("/hello")
public class GreetingResource {
@GET
@Produces(MediaType.TEXT_PLAIN)
public String hello() {
return "hello";
}
}As we want to use configuration properties obtained from the Config Server, we will update the GreetingResource to inject the message property. The updated code will look like this:
package org.acme.spring.spring.cloud.config.client;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import org.eclipse.microprofile.config.inject.ConfigProperty;
@Path("/hello")
public class GreetingResource {
@ConfigProperty(name = "message", defaultValue="hello default")
String message;
@GET
@Produces(MediaType.TEXT_PLAIN)
public String hello() {
return message;
}
}Configuring the application
Quarkus provides various configuration knobs under the quarkus.spring-cloud-config root. For the purposes of this guide, our Quarkus application is going to be configured in application.properties as follows:
# use the same name as the application name that was configured when standing up the Config Server
quarkus.application.name=a-bootiful-client
# enable retrieval of configuration from the Config Server - this is off by default
quarkus.spring-cloud-config.enabled=true
# configure the URL where the Config Server listens to HTTP requests - this could have been left out since http://localhost:8888 is the default
quarkus.spring-cloud-config.url=http://localhost:8888Package and run the application
Run the application with: ./mvnw compile quarkus:dev.
Open your browser to http://localhost:8080/greeting.
The result should be: Hello world as it is the value obtained from the Spring Cloud Config server.
Run the application as a native executable
You can of course create a native image using the instructions of the Building a native executable guide.
More Spring guides
Quarkus has more Spring compatibility features. See the following guides for more details:
Spring Cloud Config Client Reference
Configuration property fixed at build time - All other configuration properties are overridable at runtime
Type |
Default |
|
|---|---|---|
If enabled, will try to read the configuration from a Spring Cloud Config Server |
boolean |
|
If set to true, the application will not stand up if it cannot obtain configuration from the Config Server |
boolean |
|
The Base URI where the Spring Cloud Config Server is available |
string |
|
The amount of time to wait when initially establishing a connection before giving up and timing out.
Specify |
|
|
The amount of time to wait for a read on a socket before an exception is thrown.
Specify |
|
|
The username to be used if the Config Server has BASIC Auth enabled |
string |
|
The password to be used if the Config Server has BASIC Auth enabled |
string |
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About the Duration format
The format for durations uses the standard You can also provide duration values starting with a number.
In this case, if the value consists only of a number, the converter treats the value as seconds.
Otherwise, |
