一、流程:
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
@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,
3、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
二、开发步骤:
1.先创建一个空项目,在这个空项目创建两个模块
2.创建starter模块和autoconfig模块
在starter模块中引入autoconfig模块,下面是starter模块的pom文件
<?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.atguigu.starter</groupId> <artifactId>atguigu-springboot-starter</artifactId> <version>1.0-SNAPSHOT</version> <!--启动器--> <dependencies> <!--引入自动配置模块--> <dependency> <groupId>com.atguigu.starter</groupId> <artifactId>atguigu-springboot-starter-autoconfigurer</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> </dependencies> </project>
下面是starter模块的完整目录
3.修改autoconfig模块
(1)pom文件
<?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>2.2.5.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.atguigu.starter</groupId> <artifactId>atguigu-springboot-starter-autoconfigurer</artifactId> <version>0.0.1-SNAPSHOT</version> <name>atguigu-springboot-starter-autoconfigurer</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> </properties> <dependencies> <!--引入spring-boot-starter,这是所有starter必须引入的基本配置--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> </dependency> </dependencies> </project>
(2)编写HellServer类
package com.atguigu.starter; public class HelloService { HelloProperties helloProperties; public HelloProperties getHelloProperties() { return helloProperties; } public void setHelloProperties(HelloProperties helloProperties) { this.helloProperties = helloProperties; } public String sayHelloAtGuigu(String name){ return helloProperties.getPrefix()+"-"+name+"-"+helloProperties.getSuffix(); } }
(3)编写HelloProperties类
package com.atguigu.starter; import org.springframework.boot.context.properties.ConfigurationProperties; @ConfigurationProperties(prefix = "atguigu.hello")//表示读取配置文件 public class HelloProperties { private String prefix;//atguigu.hello.prefix private String suffix;//atguigu.hello.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; } }
(4)编写HelloServiceAutoConfiguration类
package com.atguigu.starter; 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//表示这是一个配置类 @ConditionalOnWebApplication//表示web应用才生效 @EnableConfigurationProperties(HelloProperties.class)//使@ConfigruationProperties注解的类生效,只有配加上这个注解,HelloProperties才会生效 public class HelloServiceAutoConfiguration { @Autowired HelloProperties helloProperties; @Bean public HelloService helloService(){ HelloService helloService = new HelloService(); helloService.setHelloProperties(helloProperties); return helloService; } }
(5)在resources文件夹下创建META-INF文件夹,在META-INF文件夹下创建spring.factories文件
下面是spring.factories文件的内容
org.springframework.boot.autoconfigure.EnableAutoConfiguration= com.atguigu.starter.HelloServiceAutoConfiguration #这里配置的是自动配置类的全路径
(6)下面是autoconfig模块的完整目录图:
4.先将autoconfig模块执行install命令,再将starter模块执行install命令
5.在需要引用此starter的项目中引用此starter
<!--引入自定义的starter--> <dependency> <groupId>com.atguigu.starter</groupId> <artifactId>atguigu-springboot-starter</artifactId> <version>1.0-SNAPSHOT</version> </dependency>
6.写Controller
package com.atguigu.controller; import com.atguigu.starter.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; @RestController public class HelloController { @Autowired HelloService helloService; @GetMapping("/hello/{name}") public String hello(@PathVariable("name") String name){ String s = helloService.sayHelloAtGuigu(name); System.err.println(s); return s; } }
7.在application.properties文件中进行配置属性
atguigu.hello.prefix=Are you atguigu.hello.suffix=?
8.启动项目进行测试即可