第八章 Spring Boot 自定义 starters
自动配置类
@Configuration // 指定这个类是配置类 @Conditionalxxx // 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 @ConfigurationProperties // 结合相关Properties类来绑定相关的配置 @EnableConfigurationProperties // 让Properties生效加入到容器中
启动器 Starter
启动器模块是一个空的 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：
推荐使用一下命名规约
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-jdbc
自定义命名空间：
前缀：-spring-boot-starter
模式：模块名-spring-boot-starter
举例：mybatis-spring-boot-starter
自定义 starter
1、Idea 创建空工程 Empty Project
2、新建 spring 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>2.3.1.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.mouday</groupId> <artifactId>mouday-spring-boot-starter-autoconfigurer</artifactId> <version>0.0.1-SNAPSHOT</version> <name>mouday-spring-boot-starter-autoconfigurer</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> </properties> <!--所有starter的基本配置--> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> </dependency> </dependencies> </project>
属性文件 HelloProperties.java
package com.mouday.starter; import org.springframework.boot.context.properties.ConfigurationProperties; @ConfigurationProperties(prefix = "mouday.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.java
package com.mouday.starter; public class HelloService { HelloProperties properties; public String sayHello(String name){ return properties.getPrefix() + name + properties.getSuffix(); } public HelloProperties getProperties() { return properties; } public void setProperties(HelloProperties properties) { this.properties = properties; } }
配置类
package com.mouday.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 @ConditionalOnWebApplication // web应用才生效 @EnableConfigurationProperties(HelloProperties.class) public class HelloServiceAutoConfiguration { @Autowired HelloProperties helloProperties; @Bean public HelloService helloService(){ HelloService service = new HelloService(); service.setProperties(helloProperties); return service; } }
src/main/resources/META-INF/spring.factories
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\ com.mouday.starter.HelloServiceAutoConfiguration
3、新建 maven starter 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 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.mouday</groupId> <artifactId>mouday-spring-boot-starter</artifactId> <version>1.0-SNAPSHOT</version> <dependencies> <dependency> <groupId>com.mouday</groupId> <artifactId>mouday-spring-boot-starter-autoconfigurer</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> </dependencies> </project>
测试
引入依赖 pom.xml
<dependency> <groupId>com.mouday</groupId> <artifactId>mouday-spring-boot-starter</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency>
修改配置文件 application.properties
mouday.hello.prefix=hello mouday.hello.suffix=hi
新建测试 Controller
package com.example.demo.controller; import com.mouday.starter.HelloService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.ResponseBody; @Controller public class HelloController { @Autowired HelloService helloService; @GetMapping("/hello") @ResponseBody public String hello(String name){ return helloService.sayHello(name); } }
http://localhost:8080/hello?name=Tom
访问结果
helloTomhi
学习新技术：
一看文档，二看源码
