一、前置知识:
maven项目打包参考连接
二、自定义starter
1.命名规范
自定义的Starter官方建议:叫xxx-spring-boot-starter。
2.新建maven项目,结构如下
![](https://img.laitimes.com/img/_0nNw4CM6IyYiwiM6ICdiwiI0gTMx81dsQWZ4lmZf1GLlpXazVmcvwFciV2dsQXYtJ3bm9CX9s2RkBnVHFmb1clWvB3MaVnRtp1XlBXe0xCMy81dvRWYoNHLwEzX5xCMx8FesU2cfdGLwMzX0xiRGZkRGZ0Xy9GbvNGLpZTY1EmMZVDUSFTU4VFRR9Fd4VGdsYTMfVmepNHLrJXYtJXZ0F2dvwVZnFWbp1zczV2YvJHctM3cv1Ce-cmbw5CO3ATM1EWNzU2NzUWOiNWYyYzX3ATOyEDM4EzLcZDMyIDMy8CXn9Gbi9CXzV2Zh1WavwVbvNmLvR3YxUjLyM3Lc9CX6MHc0RHaiojIsJye.png)
3.添加pom的依赖
紫色为重点
<?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>
<groupId>com.fast</groupId>
<artifactId>fast-spring-boot-starter</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>fast-spring-boot-starter</name>
<description>fast-spring-boot-starter</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-autoconfigure</artifactId>
<version>2.6.7</version>
</dependency>
<dependency>
<groupId>cn.hutool</groupId>
<artifactId>hutool-all</artifactId>
<version>5.7.16</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.16</version>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.1.2</version>
</dependency>
<dependency>
<groupId>com.github.xiaoymin</groupId>
<artifactId>knife4j-spring-boot-starter</artifactId>
<version>2.0.7</version>
</dependency>
</dependencies>
</project>
4.编写自己的核心代码Myservice.java
package com.fast;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
@EnableConfigurationProperties(MyService.class)
//注意:prefix的值不能用驼峰命名,springboot2.x不识别,例:myService新项目引入导致无法启动,正例:myservice或my-service
@ConfigurationProperties(prefix = "myservice")
public class MyService {
private int id;
private String name;
//构造方法,set,get,toString省略
}
5.编写自动配置类MyServiceAutoConfiguration.java
package com.fast;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class MyServiceAutoConfiguration {
static {
System.out.println("加载MyServiceAutoConfiguration");
}
@Bean
//注意紫色部分叫什么,使用@Autowaired注入的时候就叫什么
public MyService myService() {
return new MyService();
}
}
6.在Resource下新建META-INF目录,再在新目录下新建spring.factories
紫色部分为固定写法,后面跟自己的自动配置类
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\com.fast.MyServiceAutoConfiguration
7.install或上传到私服,在新项目的pom中引用即可。
测试:
1.在新项目的application.yml中添加myservice
myservice:
id: 11
name: 李四
2.在测试类中编写测试
注意:包结构和src/java下的包结构要一致,否则会报错。
package com.fast;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
@RunWith(SpringRunner.class)
@SpringBootTest
public class SysJobTest {
@Autowired
private MyService myService;
@Test
public void startTest() throws Exception {
System.out.println("myService = " + myService);
}
}
三、热插拔
如果不使用热插拔,坐标引入即意味着功能开启,如果使用了热插拔,则使用条件触发,例如:在启动类上添加指定注解才允许开启。
1.把上面的工程接着改造,结构如下
2.新增标记类ConfigMarker.java
package com.fast;
/**
* 标记类
*/
public class ConfigMarker {
}
3.新增注解开关EnableRegisterServer
package com.fast;
import org.springframework.context.annotation.Import;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
//@Import这个注解是热插拔的核心,这个注解会将ConfigMapper生成实例,并注入到容器中
@Import({ConfigMarker.class})
public @interface EnableRegisterServer {
}
4.改造自动配置类
注意紫色部分,改造好之后,重新install或上传到私服
package com.fast;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
//检测到容器中有ConfigMarker实例存在,就会自动加载下面的代码,反之,不加载
@ConditionalOnBean(ConfigMarker.class)
public class MyServiceAutoConfiguration {
static {
System.out.println("加载MyServiceAutoConfiguration");
}
@Bean
public MyService myService() {
return new MyService();
}
}
5.在新项目中的启动类上添加开关注解
package com.fast;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.DependsOn;
@SpringBootApplication
//注掉这个注解,则项目启动时不会加载fast-spring-boot-starter的myService,所以容器中没有这个对象;
//放开这个注解,则项目启动时会在ioc容器中注入myService实例,做到了自动加载自定义starter
@EnableRegisterServer
@MapperScan("com.fast.dao")
public class FastBootApplication {
public static void main(String[] args) {
SpringApplication.run(FastBootApplication.class, args);
}
}