一、簡(jiǎn)介
SpringBoot 最強(qiáng)大的功能就是把我們常用的場(chǎng)景抽取成了一個(gè)個(gè)starter（場(chǎng)景啟動(dòng)器），我們通過(guò)引入SpringBoot 為我提供的這些場(chǎng)景啟動(dòng)器，我們?cè)龠M(jìn)行少量的配置就能使用相應(yīng)的功能。即使是這樣，SpringBoot也不能囊括我們所有的使用場(chǎng)景，往往我們需要自定義starter，來(lái)簡(jiǎn)化我們對(duì)SpringBoot的使用。
下面話不多說(shuō)了，來(lái)一起看看詳細(xì)的介紹吧
二、如何自定義starter
1.實(shí)例
如何編寫(xiě)自動(dòng)配置 ？
我們參照@WebMvcAutoConfiguration為例，我們看看需要準(zhǔn)備哪些東西，下面是WebMvcAutoConfiguration的部分代碼：
@Configuration@ConditionalOnWebApplication@ConditionalOnClass({Servlet.class, DispatcherServlet.class, WebMvcConfigurerAdapter.class})@ConditionalOnMissingBean({WebMvcConfigurationSupport.class})@AutoConfigureOrder(-2147483638)@AutoConfigureAfter({DispatcherServletAutoConfiguration.class, ValidationAutoConfiguration.class})public class WebMvcAutoConfiguration { @Import({WebMvcAutoConfiguration.EnableWebMvcConfiguration.class}) @EnableConfigurationProperties({WebMvcProperties.class, ResourceProperties.class}) public static class WebMvcAutoConfigurationAdapter extends WebMvcConfigurerAdapter { @Bean @ConditionalOnBean({View.class}) @ConditionalOnMissingBean public BeanNameViewResolver beanNameViewResolver() { BeanNameViewResolver resolver = new BeanNameViewResolver(); resolver.setOrder(2147483637); return resolver; } }}我們可以抽取到我們自定義starter時(shí),同樣需要的一些配置。
@Configuration //指定這個(gè)類是一個(gè)配置類@ConditionalOnXXX //指定條件成立的情況下自動(dòng)配置類生效@AutoConfigureOrder //指定自動(dòng)配置類的順序@Bean //向容器中添加組件@ConfigurationProperties //結(jié)合相關(guān)xxxProperties來(lái)綁定相關(guān)的配置@EnableConfigurationProperties //讓xxxProperties生效加入到容器中自動(dòng)配置類要能加載需要將自動(dòng)配置類，配置在META-INF/spring.factories中org.springframework.boot.autoconfigure.EnableAutoConfiguration=/org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration,/org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,/
模式
我們參照 spring-boot-starter 我們發(fā)現(xiàn)其中沒(méi)有代碼：
我們?cè)诳此膒om中的依賴中有個(gè) springboot-starter
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId></dependency>
我們?cè)倏纯?spring-boot-starter 有個(gè) spring-boot-autoconfigure
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-autoconfigure</artifactId></dependency>
關(guān)于web的一些自動(dòng)配置都寫(xiě)在了這里 ，所以我們有以下總結(jié)：
啟動(dòng)器starter只是用來(lái)做依賴管理
需要專門寫(xiě)一個(gè)類似spring-boot-autoconfigure的配置模塊
用的時(shí)候只需要引入啟動(dòng)器starter，就可以使用自動(dòng)配置了
命名規(guī)范
官方命名空間
自定義命名空間
三、自定義starter實(shí)例
我們需要先創(chuàng)建兩個(gè)工程 hello-spring-boot-starter 和 hello-spring-boot-starter-autoconfigurer
1. hello-spring-boot-starter
1.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 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.gf</groupId> <artifactId>hello-spring-boot-starter</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>hello-spring-boot-starter</name> <!-- 啟動(dòng)器 --> <dependencies> <!-- 引入自動(dòng)配置模塊 --> <dependency> <groupId>com.gf</groupId> <artifactId>hello-spring-boot-starter-autoconfigurer</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> </dependencies></project>
同時(shí)刪除 啟動(dòng)類、resources下的文件，test文件。
2. hello-spring-boot-starter-autoconfigurer
1. 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 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.gf</groupId> <artifactId>hello-spring-boot-starter-autoconfigurer</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>hello-spring-boot-starter-autoconfigurer</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.9.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <!-- 引入spring-boot-starter，所有starter的基本配合 --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> </dependency> </dependencies></project>
2. HelloProperties
package com.gf.service;import org.springframework.boot.context.properties.ConfigurationProperties;@ConfigurationProperties(prefix = "gf.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; }}3. HelloService
package com.gf.service;public class HelloService { HelloProperties helloProperties; public HelloProperties getHelloProperties() { return helloProperties; } public void setHelloProperties(HelloProperties helloProperties) { this.helloProperties = helloProperties; } public String sayHello(String name ) { return helloProperties.getPrefix()+ "-" + name + helloProperties.getSuffix(); }}4. HelloServiceAutoConfiguration
package com.gf.service;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應(yīng)該生效@EnableConfigurationProperties(HelloProperties.class)public class HelloServiceAutoConfiguration { @Autowired HelloProperties helloProperties; @Bean public HelloService helloService() { HelloService service = new HelloService(); service.setHelloProperties( helloProperties ); return service; }}5. spring.factories
在 resources 下創(chuàng)建文件夾 META-INF 并在 META-INF 下創(chuàng)建文件 spring.factories ，內(nèi)容如下：
# Auto Configureorg.springframework.boot.autoconfigure.EnableAutoConfiguration=/com.gf.service.HelloServiceAutoConfiguration
到這兒，我們的配置自定義的starter就寫(xiě)完了 ，我們把 hello-spring-boot-starter-autoconfigurer、hello-spring-boot-starter 安裝成本地jar包。
三、測(cè)試自定義starter
我們創(chuàng)建個(gè)項(xiàng)目 hello-spring-boot-starter-test，來(lái)測(cè)試系我們寫(xiě)的stater。
1. 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 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.gf</groupId> <artifactId>hello-spring-boot-starter-test</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>hello-spring-boot-starter-test</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.9.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <!-- 引入自定義starter --> <dependency> <groupId>com.gf</groupId> <artifactId>hello-spring-boot-starter</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build></project>
2. HelloController
package com.gf.controller;import com.gf.service.HelloService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.RestController;@RestControllerpublic class HelloController { @Autowired HelloService helloService; @GetMapping("/hello/{name}") public String hello(@PathVariable(value = "name") String name) { return helloService.sayHello( name + " , " ); }}3. application.properties
gf.hello.prefix = higf.hello.suffix = what's up man ?
我運(yùn)行項(xiàng)目訪問(wèn) http://127.0.0.1:8080/hello/zhangsan，結(jié)果如下：
hi-zhangsan , what's up man ?
源碼下載: https://github.com/gf-huanchupk/SpringBootLearning
總結(jié)
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