Springboot source code – Custom starter

Starter is the wing of spring boot. If you insert the wings, you can fly very high~

Students who want to fly, follow me and DIY their own starter step by step~

1. Create POM project

Create a POM project named sayhello spring boot starter and introduce two dependencies, as shown in the figure:

2. Create bean

SayHello.java

package bean;

public class SayHello {
    //There is only one attribute
    private String name;
    
    public void setName(String name){
        this.name = name;
    }
    //Last output information
    public String getMsg(){
        return name + "say hello~~";
    }
}

3. Create the properties class

SayHelloProperties.java

package properties;
import org.springframework.boot.context.properties.ConfigurationProperties;
//Read the configuration of Hello: name in the configuration file
@ConfigurationProperties(prefix = "hello")
public class SayHelloProperties {

    private String name;

    public String getName(){
        return name;
    }

    public void setName(String name){
        this.name = name;
    }
}

4. Create automatic configuration class

MyAutoConfiguration.java

@Configuration
@ConditionalOnClass(SayHello.class)
@EnableConfigurationProperties(SayHelloProperties.class)
public class MyAutoConfiguration {

    @Autowired
    SayHelloProperties sayHelloProperties;

    @Bean
    @ConditionalOnMissingBean(SayHello.class)
    public SayHello getSayHiService(){
        SayHello sayHello = new SayHello();
        //Get the name from the configuration file. The bean sayhello is initialized
        sayHello.setName(sayHelloProperties.getName());
        return sayHello;
    }
}

After reading the chapter on the principle of automatic configuration, the code looks very simple~

5. Create spring factories

In the resources / meta-inf directory, create spring.inf The contents of the factories file are automatic configuration classes

spring.factories

org.springframework.boot.autoconfigure.EnableAutoConfiguration= MyAutoConfiguration

When the project starts, you can automatically assemble myautoconfiguration

The overall structure of the project is as follows:

6. Maven packaging project

Package the project with the command MVN clean install to get the jar package sayhello-spring-boot-starter-1.0-snapshot jar

Next, you can upload the jar package to Maven private server or import it into another project by importing. Here, the latter is used. Operate in another project:

7. Configure Hello: name value

server:
  port: 9000

hello:
  name: wangdaye-

8. Create test controller

TestController.java

@RestController
@RequestMapping("/test")
public class TestController {

    @Autowired
    SayHello sayHello;

    @GetMapping("/hello")
    public String hello(){
        return sayHello.getMsg();
    }
}

Visit localhost: 9000 / test / Hello from the browser

Uncle Wang said hello to you, see~~