08_springboot2.x自定义starter

谁践踏了优雅 2023-06-04 08:55 2阅读 0赞

### 概述 ###

**starter：启动器  
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**

**规则：**

@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**

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
    org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration,\
    org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,\

**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）  
mybatis-spring-boot-starter；自定义启动器名-spring-boot-starter**

**启动器（starter）  
–启动器模块是一个空JAR 文件，仅提供辅助性依赖管理，这些依赖可能用于自动装配或者其他类库**

**命名规约：  
•推荐使用以下命名规约**

**官方命名空间  
–前缀：“spring-boot-starter-”  
–模式：spring-boot-starter-模块名  
–举例：spring-boot-starter-web、spring-boot-starter-actuator、spring-boot-starter-jdbc**

**自定义命名空间  
–后缀：“-spring-boot-starter”  
–模式：模块-spring-boot-starter  
–举例：mybatis-spring-boot-starter**

**图解**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2phdHBlbg_size_16_color_FFFFFF_t_70][]

**1、编写启动器XXX-starter**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2phdHBlbg_size_16_color_FFFFFF_t_70 1][]

**2、自动配置模块**

**pom.xml**

<?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>2.1.9.RELEASE</version>
            <relativePath/> 
        </parent>
        <groupId>com.spboot</groupId>
        <artifactId>jatpeo-spring-boot-starter-autoconfigurer</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>jatpeo-spring-boot-starter-autoconfigurer</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>

应用举例:

HelloProperties 配置文件

package com.spboot.starter;
    
    import org.springframework.boot.context.properties.ConfigurationProperties;
    
    @ConfigurationProperties(prefix = "jatpeo.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;
        }
    }

HelloService

package com.spboot.starter;
    
    public class HelloService {
    
        HelloProperties helloProperties;
    
    
        public String sayHello(String name){
    
        return helloProperties.getPrefix()+ name + helloProperties.getSuffix();
        }
    
        public HelloProperties getHelloProperties() {
            return helloProperties;
        }
    
        public void setHelloProperties(HelloProperties helloProperties) {
            this.helloProperties = helloProperties;
        }
    }

自动配置类：

HelloServiceAutoConfiguration

package com.spboot.starter;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
    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应用起效果
    @EnableConfigurationProperties(HelloProperties.class)
    public class HelloServiceAutoConfiguration {
    
        @Autowired
        HelloProperties helloProperties;
    
        @Bean
        public HelloService helloService(){
            HelloService helloService = new HelloService();
            helloService.setHelloProperties(helloProperties);
            return helloService;
        }
    }

**注意：这里让自动配置类生效得在META-INF/新建spring.factories**

![20191007204102740.png][]

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
    com.spboot.starter.HelloServiceAutoConfiguration

**分别安装到maven仓库**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2phdHBlbg_size_16_color_FFFFFF_t_70 2][]

注意安装顺序

### 测试： ###

**新建项目**

pom.xml

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2phdHBlbg_size_16_color_FFFFFF_t_70 3][]

注意：引用的是我们配置的启动器的

**application.properties**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2phdHBlbg_size_16_color_FFFFFF_t_70 4][]

**controller:**

package com.spboot.springboot.controller;
    
    import com.spboot.starter.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 say(){
            return helloService.sayHello("dyn");
        }
    
    }

**浏览器测试：**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2phdHBlbg_size_16_color_FFFFFF_t_70 5][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2phdHBlbg_size_16_color_FFFFFF_t_70]: /images/20230601/ba96e854bb1a498196b387b35c5e577a.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2phdHBlbg_size_16_color_FFFFFF_t_70 1]: /images/20230601/4e9006d90d054c97ad1b7d381e9b6828.png
[20191007204102740.png]: /images/20230601/f2cc0d484df348f3b7d9b249c0a1f51b.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2phdHBlbg_size_16_color_FFFFFF_t_70 2]: /images/20230601/7954ba5903b84f8ea996b804bce081ba.png
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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2phdHBlbg_size_16_color_FFFFFF_t_70 5]: /images/20230601/7282165980f44e888a18eea93f6bead3.png