Alibaba Micro Service expert handwriting Spring Boot implements a simple auto-configuration module

To better understand how Spring Boot is automatically configured and how it works, we implement a simple automatic configuration module ourselves.

Suppose, now the project needs a function, need to automatically record the project publisher's relevant information, how can we use Spring Boot automatic configuration, better implementation of the function?

The beginning of actual combat –maven construction

To create a MAVEN project, let me manually configure the next POM file.

Configuration of Parameters-attribute parameter class

First, we define a custom prefix, called Custom. As mentioned before, the configuration parameters here can be set directly through the application.properties. Well, we create a field for the author, set the default value to Lianggzone.

So, smart you, should think of, we in the application.properties configuration, it is necessary to configure this.

#custom

Custom.author = James

It's really simple.-Simple service class

You are not mistaken, it is really too simple, no tall on the complex business. Its main purpose is to assign values.

Automatic configuration of the core-automatic configuration class

@ConditionalOnClass, the corresponding class in the parameter will not parse the corresponding configuration class until it exists in the Classpath directory. Therefore, we need to configure Authorserver.

@EnableConfigurationProperties that is used to load configuration parameters, so it should be the attribute parameter class

Authorproperties.

The function of the Authorresolver method, that is, the authorproperties parameter is assigned to Authorserver.

Spring.factories Don't miss it.

When we need to implement custom automatic assembly, we need to customize the spring.factories parameter. So, we need to configure the information in the src/main/resources/meta-inf/spring.factories, it is worth noting that this file is to be created by itself.

Feature packaging and configuration dependencies

Well, we've implemented a simple auto-configuration feature. Well, we need to put this project into a jar package deployed on our local or on-premises. Then, you can use it.

In another project, we configured Maven dependencies.

Test, test

Run up and we look at what publisher information is printed?

We configure a message in the application.properties.

#custom

Custom.author = James

Run up and we look at what publisher information is printed?

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Alibaba Micro Service expert handwriting Spring Boot implements a simple auto-configuration module