springboot starter自定义实现公共模块方式

SpringBoot中的starter是一种非常重要的机制，能够抛弃以前繁杂的配置，将其统一集成进starter，应用者只需要在maven中引入starter依赖，SpringBoot就能自动扫描到要加载的信息并启动相应的默认配置。

我们将可独立于业务代码之外的功配置模块封装成一个个starter，复用的时候只需要将其在pom中引用依赖即可，SpringBoot为我们完成自动装配。

比如登录模块，基于aop的日志模块等。

SpringBoot提供的starter以spring-boot-starter-xxx的方式命名的。官方建议自定义的starter使用xxx-spring-boot-starter命名规则。以区分SpringBoot生态提供的starter。

以下是定义一个starter的步骤：

1. 建立一个父项目

<?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>2.3.9.RELEASE</version>
    </parent>

    <groupId>org.example</groupId>
    <artifactId>springboot-starter-demo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>springboot-starter-config</module>
        <module>springboot-starter-application</module>
    </modules>

    <packaging>pom</packaging>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

</project>

2. 新建一个maven module项目作为自定义starter项目

pom.xml如下：

<?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">

    <parent>
        <artifactId>springboot-starter-demo</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springboot-starter-config</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
    </dependencies>

</project>

3. 定义属性类

package com.demo;

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

/**
 * 描述：配置信息 实体
 *
 **/
@ConfigurationProperties(prefix = "demo")
public class DemoProperties {
    private String params1;
    private String params2;
    private Integer minLength;


    public String getParams1() {
        return params1;
    }

    public void setParams1(String params1) {
        this.params1 = params1;
    }

    public String getParams2() {
        return params2;
    }

    public void setParams2(String params2) {
        this.params2 = params2;
    }

    public Integer getMinLength() {
        return minLength;
    }

    public void setMinLength(Integer minLength) {
        this.minLength = minLength;
    }
}

4. 定义服务类

package com.demo.service;

import com.demo.DemoProperties;
import org.springframework.beans.factory.annotation.Autowired;

/**
 * author:HUAWEI
 */
public class DemoService {

    @Autowired
    private DemoProperties demoProperties;

    public String params1;
    public String params2;

    public DemoService(String param1, String param2) {
        this.params1 = param1;
        this.params2 = param2;
    }

    public String paramsInfo() {
        return this.params1 + "!  " + params2;
    }

    public boolean isValidLength(String param) {

        int length = param.length();
        Integer minLength = demoProperties.getMinLength();

        if (length < minLength.intValue()) {
            return false;
        } else {
            return true;
        }

    }
}

5. 定义配置类

package com.demo;

import com.demo.service.DemoService;
import org.springframework.beans.factory.annotation.Autowired;
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;

/**
 * 描述：配置类
 *
 **/
@Configuration
@EnableConfigurationProperties(DemoProperties.class)
@ConditionalOnProperty(
        prefix = "demo",
        name = "enable",
        havingValue = "true"
)
public class DemoStarterAutoConfig {
    @Autowired
    private DemoProperties demoProperties;

    @Bean(name = "demo")
    public DemoService demoService(){
        return new DemoService(demoProperties.getParams1(), demoProperties.getParams2());
    }
}

6. 重要的一步

resource目录下添加META-INF目录，在其下面建立文件spring.factories，内容如下：

org.springframework.boot.autoconfigure.EnableAutoConfiguration=com.demo.DemoStarterAutoConfig

经过以上步骤，starter就完成了。

以下是建立测试项目的步骤。

7. 建立maven module测试项目

<?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">
    <parent>
        <artifactId>springboot-starter-demo</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springboot-starter-application</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.example</groupId>
            <artifactId>springboot-starter-config</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
    </dependencies>

</project>

8. 添加配置文件application.yml

server:
  port: 8010


demo:
  enable: true
  params1: 参数1
  params2: 参数2
  minLength: 4

9. 添加测试controller

package com.demo.starter.controller;

import com.demo.service.DemoService;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;


@RestController
public class AppController {

    @Resource(name = "demo")
    private DemoService demoService;

    @GetMapping("/test")
    public String test(){

        boolean valid = demoService.isValidLength("test");
        if(valid)
            return demoService.paramsInfo();
        else
            return "无效数据";
    }
}

10. 打开浏览器，执行测试

自此完成了starter的基本测试。

总结

以上为个人经验，希望能给大家一个参考，也希望大家多多支持。