怎么样写一个starter

首先我们创建一个maven 工程，创建方式会以注释形式给出，接下来我们开始贴代码，嘿嘿嘿

工程目录结构如下

pom文件如下

<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.test.ll</groupId>
  <artifactId>starter</artifactId>
  <version>1.0-SNAPSHOT</version>

  <name>starter</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
  </properties>

  <dependencies>
    <!--创建maven工程 idea 点击file -点击project - 点击maven -选择阿帕奇 quickstart （如果选择不了，点击 create from ），创建maven工程完毕  -->
    <!--手动修改pom文件-->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-actuator-autoconfigure</artifactId>
      <version>2.0.3.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
  </dependencies>

  <build>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-jar-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
        <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
        <plugin>
          <artifactId>maven-site-plugin</artifactId>
          <version>3.7.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-project-info-reports-plugin</artifactId>
          <version>3.0.0</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

代码如下

@ConfigurationProperties(prefix = "hello")
public class HelloMsg {
    private String hello = "girlFriends";

    public String getHello() {
        return hello;
    }

    public void setHello(String hello) {
        this.hello = hello;
    }
    }

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
@EnableConfigurationProperties(HelloMsg.class)
@ConditionalOnClass(HelloService.class)
@ConditionalOnProperty(prefix = "hello", value = "enabled", matchIfMissing = true)
public class HelloAutoConfig {
    @Autowired
    private HelloMsg helloMsg;

    /**
     * @return
     * @Configuration + @bean 相当于 xml 中的bean 标签  spring会进行管理
     */
    @Bean
    public HelloService helloService() {
        HelloService helloService = new HelloService();
        helloService.setMsg(helloMsg.getHello());
        return helloService;
    }
}

spring.factories （文件名）
org.springframework.boot.autoconfigure.EnableAutoConfiguration=com.test.ll.HelloAutoConfig

public class HelloService {

    private String msg;

    public String sayHello() {
        return "hello," + msg;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }
}

import org.springframework.boot.context.properties.ConfigurationProperties;
@ConfigurationProperties(prefix = "hello")
public class HelloMsg {
    private String hello = "girlFriends";

    public String getHello() {
        return hello;
    }

    public void setHello(String hello) {
        this.hello = hello;
    }
}
```package com.example.demo;

import com.test.ll.HelloService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@SpringBootApplication
public class DemoApplication {

    @Autowired
    private HelloService helloService;

    @RequestMapping("/")
    public String getMsg(){
        return helloService.sayHello();
    }
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

pom文件主要引入刚才创建的maven工程，创建springboot工程就很简单了，如下图所示

springbootweb工程目录如下

或者直接访问图中链接，然后解压jar包都是可以的，具体原理之后会还会写出来