一、简介
SpringBoot 最强大的功能就是把我们常用的场景抽取成了一个个starter（场景启动器），我们通过引入SpringBoot 为我提供的这些场景启动器，我们再进行少量的配置就能使用相应的功能。即使是这样，SpringBoot也不能囊括我们所有的使用场景，往往我们需要自定义starter，来简化我们对SpringBoot的使用。
下面话不多说了，来一起看看详细的介绍吧
二、如何自定义starter
1.实例
如何编写自动配置 ？
我们参照@WebMvcAutoConfiguration为例，我们看看需要准备哪些东西，下面是WebMvcAutoConfiguration的部分代码：
@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; } }} 我们可以抽取到我们自定义starter时,同样需要的一些配置。
@Configuration //指定这个类是一个配置类@ConditionalOnXXX //指定条件成立的情况下自动配置类生效@AutoConfigureOrder //指定自动配置类的顺序@Bean //向容器中添加组件@ConfigurationProperties //结合相关xxxProperties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需要将自动配置类，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
我们参照 spring-boot-starter 我们发现其中没有代码：
我们在看它的pom中的依赖中有个 springboot-starter
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId></dependency>
我们再看看 spring-boot-starter 有个 spring-boot-autoconfigure
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-autoconfigure</artifactId></dependency>
关于web的一些自动配置都写在了这里 ，所以我们有以下总结：
启动器starter只是用来做依赖管理
需要专门写一个类似spring-boot-autoconfigure的配置模块
用的时候只需要引入启动器starter，就可以使用自动配置了
命名规范
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-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
三、自定义starter实例
我们需要先创建两个工程 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> <!-- 启动器 --> <dependencies> <!-- 引入自动配置模块 --> <dependency> <groupId>com.gf</groupId> <artifactId>hello-spring-boot-starter-autoconfigurer</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> </dependencies></project>
同时删除 启动类、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应该生效@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 下创建文件夹 META-INF 并在 META-INF 下创建文件 spring.factories ，内容如下：
# Auto Configureorg.springframework.boot.autoconfigure.EnableAutoConfiguration=/com.gf.service.HelloServiceAutoConfiguration
到这儿，我们的配置自定义的starter就写完了 ，我们把 hello-spring-boot-starter-autoconfigurer、hello-spring-boot-starter 安装成本地jar包。
三、测试自定义starter
我们创建个项目 hello-spring-boot-starter-test，来测试系我们写的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> <!-- 引入自定义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 ?
我运行项目访问 http://127.0.0.1:8080/hello/zhangsan，结果如下：
hi-zhangsan , what's up man ?
源码下载: https://github.com/gf-huanchupk/SpringBootLearning
总结
以上就是这篇文章的全部内容了，希望本文的内容对大家的学习或者工作具有一定的参考学习价值，谢谢大家对VeVb武林网的支持。
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