[Java知识库]基于springboot2.5.5自建启动器starter制品库

【README】

本文po出了自建springboot 启动器步骤；

【1】新建2个starter相关组件

根据? mybatis-spring-boot-starter，我们看到 自建starter需要两个组件，分别是 xxx-spring-boot-starter， xxx-spring-boot-starter-autoconfigure ；

其中，xxx-spring-boot-starter负责引入 xxx-spring-boot-starter-autoconfigure 依赖； xxx-spring-boot-starter-autoconfigure 负责定义相关配置；

step1，新建空项目 ；

项目名称为： springbt-08-starter-diy2；

step2，在空项目上新建2个组件，分别为

lisi-spring-boot-starter 和 lisi-spring-boot-starter-autoconfigure；

其中， lisi-spring-boot-starter为 单纯的maven项目；

?lisi-spring-boot-starter-autoconfigure 通过 spring Initializer 工具创建；

step3， lisi-spring-boot-starter 引入 lisi-spring-boot-starter-autoconfigure 依赖；

lisi-spring-boot-starter组件的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">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.cmc.starter</groupId>
    <artifactId>lisi-spring-boot-starter</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <!--引入 lisi-spring-boot-starter-autoconfigure 依赖-->
        <dependency>
            <groupId>com.cmc.starter</groupId>
            <artifactId>lisi-spring-boot-starter-autoconfigure</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>
    </dependencies>

</project>

并把测试目标目录删除， lisi-spring-boot-starter目录结构如下：

?step4， lisi-spring-boot-starter-autoconfigure 组件的pom.xml 如下：

（删除多余的插件， 测试库依赖）

<?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 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>2.5.5</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.cmc.starter</groupId>
    <artifactId>lisi-spring-boot-starter-autoconfigure</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>lisi-spring-boot-starter-autoconfigure</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
    </dependencies>

</project>

【2】开发 starter-autoconfigure 启动器配置组件

step1， 新建 HelloService，HelloProperties， HelloServiceAutoConfiguration ；

package com.cmc.starter.lisi;

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

@ConfigurationProperties(prefix = "cmc.hello")
public class HelloProperties {
    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;
    }
}

package com.cmc.starter.lisi;

public class HelloService {

    HelloProperties helloProperties;

    public String sayHelloCmc(String name) {
        return helloProperties.getPrefix() + "-" + name + "-" + helloProperties.getSuffix();
    }

    public HelloProperties getHelloProperties() {
        return helloProperties;
    }

    public void setHelloProperties(HelloProperties helloProperties) {
        this.helloProperties = helloProperties;
    }
}

package com.cmc.starter.lisi;

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(HelloProperties.class) // 使属性文件生效
public class HelloServiceAutoConfiguration {

    @Autowired
    HelloProperties helloProperties;
    @Bean
    public HelloService helloService() {
        HelloService helloService = new HelloService();
        helloService.setHelloProperties(helloProperties);
        return helloService;
    }
}

step2，在资源类路径下新建 META-INF/spring.factories 属性文件；添加 自动配置类全限定类名；

# spring.factories

# Auto Config
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
com.cmc.starter.lisi.HelloServiceAutoConfiguration

参考的是 spring-boot-autoconfigure.jar 中的 META-INF/spring.factories的内容；

目录结构如下：

step3，先把 lisi-spring-boot-starter-autoconfigure 制品库安装到本地仓库

step4，再把 lisi-spring-boot-starter 制品库安装到本地仓库；

【3】自建starter使用

step1， 新建项目，只需要引入 lisi-spring-boot-starter依赖? 即可， 因为 lisi-spring-boot-starter? 引入了 lisi-spring-boot-starter-autoconfigure，传递依赖；

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 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>2.5.5</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.cmc</groupId>
    <artifactId>springboot-08-starter-test2</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot-08-starter-test2</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <!--引入自定义的starter-->
        <dependency>
            <groupId>com.cmc.starter</groupId>
            <artifactId>lisi-spring-boot-starter</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <!-- 测试库 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- springboot web库 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

step2， 新建测试项目；编写 Controller，引入 HelloService

import com.cmc.starter.lisi.HelloService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {

    @Autowired
    HelloService helloService;

    @GetMapping("/hello")
    public String hello() {
        return helloService.sayHelloCmc("zhangsan");
    }
}

step3，HelloServiceAutoConfiguration有两个属性前缀后缀，需要配置；在 application.properties 中配置如下：

cmc.hello.prefix=chengdu
cmc.hello.suffix=028

step4，启动springboot项目，并访问

localhost:8080/hello ;