13.自定义starter启动器

starter：

​ 1、这个场景需要使用到的依赖是什么？

​ 2、如何编写自动配置

@Configuration  //指定这个类是一个配置类
@ConditionalOnXXX  //在指定条件成立的情况下自动配置类生效
@AutoConfigureAfter  //指定自动配置类的顺序
@Bean  //给容器中添加组件
 
@ConfigurationPropertie结合相关xxxProperties类来绑定相关的配置
@EnableConfigurationProperties //让xxxProperties生效加入到容器中
 
//自动配置类要能加载
//将需要启动就加载的自动配置类，配置在META-INF/spring.factories
eg：
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration,\
org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,\

​ 3、模式：

启动器只用来做依赖导入；

专门来写一个自动配置模块；

启动器依赖自动配置；别人只需要引入启动器（starter）

命名：自定义启动器名-spring-boot-starter eg：mybatis-spring-boot-starter；

步骤：

1）、启动器模块

引入自动配置模块依赖

<?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>
 
    <groupId>com.stt.mystarter</groupId>
    <artifactId>home-springboot-mystarter</artifactId>
    <version>1.0.0-SNAPSHOT</version>
 
    <!--启动器-->
    <dependencies>
        <!--引入自动配置模块-->
        <dependency>
            <groupId>com.stt.mystarter</groupId>
            <artifactId>home-springboot-myspringbootstarter-autoconfigurer</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>
    </dependencies>
</project>

2）、自动配置模块

引入spring-boot-starter依赖，这是starter最基本的，也是必须的

<?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 https://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>1.5.10.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.stt.mystarter</groupId>
	<artifactId>home-springboot-myspringbootstarter-autoconfigurer</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>home-springboot-myspringbootstarter-autoconfigurer</name>
	<description>Demo project for Spring Boot</description>
	<packaging>jar</packaging>
 
	<properties>
		<java.version>1.8</java.version>
	</properties>
 
	<dependencies>
		<!--引入spring-boot-starter依赖，所有starter基本配置-->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter</artifactId>
		</dependency>
	</dependencies>
</project>

自动配置类删除启动类与主配置文件：

组件类：HelloService

package com.stt.mystarter;
 
public class HelloService {
	// 注入属性类，提供get、set方法
    private HelloProperites helloProperites;
 
    public HelloProperites getHelloProperites() {
        return helloProperites;
    }
 
    public void setHelloProperites(HelloProperites helloProperites) {
        this.helloProperites = helloProperites;
    }
	// 配置组件功能
    public String sayHello(String name){
        return helloProperites.getPrefix()+"-"+name+"-"+helloProperites.getSuffix();
    }
}
 

属性类：HelloProperites

package com.stt.mystarter;
 
import org.springframework.boot.context.properties.ConfigurationProperties;
 
@ConfigurationProperties(prefix = "myspring.mystarter")
public class HelloProperites {
    private String prefix;
    private String suffix;
 
    public String getPrefix() {
        return prefix;
    }
 
    public void setPrefix(String prefix) {
        this.prefix = prefix;
    }
 
    public String getSuffix() {
        return suffix;
    }
 
    public void setSuffix(String suffix) {
        this.suffix = suffix;
    }
}
 

自动配置类：HelloServiceAutoConfigration

package com.stt.mystarter;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
 
@Configuration
@ConditionalOnWebApplication  // web应用才生效
@EnableConfigurationProperties(HelloProperites.class)  // 关联HelloProperites
public class HelloServiceAutoConfigration {
 
    @Autowired
    HelloProperites helloProperites;
 
    @Bean  // 组件类注入容器中
    public HelloService helloService(){
        HelloService helloService = new HelloService();
        helloService.setHelloProperites(helloProperites);
        return helloService;
    }
}
 

配置类路径文件：

自动配置类要能加载，将需要启动就加载的自动配置类，配置在META-INF/spring.factories

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
com.stt.mystarter.HelloServiceAutoConfigration  // 自动配置类的全路径名

先将自动配置类模块安装到本地仓库中,再安装启动器模块：

测试: 新建工程

pom.xml

<!--引入自定义的starter-->
<dependency>
    <groupId>com.stt.mystarter</groupId>
    <artifactId>home-springboot-mystarter</artifactId>
    <version>1.0.0-SNAPSHOT</version>
</dependency>

controller:

package com.example.demo.controller;
 
import com.stt.mystarter.HelloService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
 
@RestController
public class HelloController {
    @Autowired
    HelloService helloService;
 
    @GetMapping("/hello/{name}")
    public String printHello(@PathVariable("name") String name){
        return helloService.sayHello(name);
    }
}
 

application.properties

myspring.mystarter.prefix=sxl
myspring.mystarter.suffix=sh

结果：