开发

第一步：创建starter工程hello-spring-boot-starter并配置pom.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 
                             http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.2.RELEASE</version>
        <relativePath/>
    </parent>
    <groupId>cn.itcast</groupId>
    <artifactId>hello-spring-boot-starter</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-autoconfigure</artifactId>
        </dependency>
    </dependencies>
</project>

第二步：创建配置属性类HelloProperties

package cn.itcast.config;

import org.springframework.boot.context.properties.ConfigurationProperties;

/*
 *读取配置文件转换为bean
 * */
@ConfigurationProperties(prefix = "hello")
public class HelloProperties {
    private String name;
    private String address;

    public String getName() {
        return name;
    }

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

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "HelloProperties{" +
                "name='" + name + '\'' +
                ", address='" + address + '\'' +
                '}';
    }
}

第三步：创建服务类HelloService

package cn.itcast.service;

public class HelloService {
    private String name;
    private String address;

    public HelloService(String name, String address) {
        this.name = name;
        this.address = address;
    }

    public String sayHello(){
        return "你好！我的名字叫 " + name + "，我来自 " + address;
    }
}

第四步：创建自动配置类HelloServiceAutoConfiguration

package cn.itcast.config;

import cn.itcast.service.HelloService;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/*
* 配置类，基于Java代码的bean配置
* */

@Configuration
@EnableConfigurationProperties(HelloProperties.class)
public class HelloServiceAutoConfiguration {
    private HelloProperties helloProperties;

    //通过构造方法注入配置属性对象HelloProperties
    public HelloServiceAutoConfiguration(HelloProperties helloProperties) {
        this.helloProperties = helloProperties;
    }

    //实例化HelloService并载入Spring IoC容器
    @Bean
    @ConditionalOnMissingBean
    public HelloService helloService(){
        return new HelloService(helloProperties.getName(),helloProperties.getAddress());
    }
}

第五步：在resources目录下创建META-INF/spring.factories

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
cn.itcast.config.HelloServiceAutoConfiguration

至此starter已经开发完成了，可以将当前starter安装到本地maven仓库供其他应用来使用。

使用