自己实现一个简单的例子,当某个类存在的时候,自动配置这个Bean,并且可以讲这个属性在application.properties中配置
新建一个maven项目(需要引入 spring-boot-autoconfigure)
Pom.xml
<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.ibigsea</groupId> <artifactId>spring-boot-starter-hello</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>spring-boot-starter-hello</name> <url>http://maven.apache.org</url> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-autoconfigure</artifactId> <version>1.3.3.RELEASE</version> </dependency> </dependencies> </project>
package com.ibigsea.spring_boot_starter_hello; /** * 通过application.properties的hello.msg来配置,默认为world * @author bigsea * */ public class Hello { private String msg; public String sayHello() { return "hello " + msg; } public String getMsg() { return msg; } public void setMsg(String msg) { this.msg = msg; } }
HelloProperties.java
package com.ibigsea.spring_boot_starter_hello; import org.springframework.boot.context.properties.ConfigurationProperties; /** * 属性配置,Spring boot 自身的自动配置 * @author bigsea * */ @ConfigurationProperties(prefix="hello") public class HelloProperties { private static final String MSG = "world"; private String msg = MSG ; public String getMsg() { return msg; } public void setMsg(String msg) { this.msg = msg; } }
HelloAutoConfiguration.java
package com.ibigsea.spring_boot_starter_hello; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.autoconfigure.condition.ConditionalOnClass; import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean; import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty; import org.springframework.boot.context.properties.EnableConfigurationProperties; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; @Configuration @EnableConfigurationProperties(HelloProperties.class)//开启属性注入,通过@autowired注入 @ConditionalOnClass(Hello.class)//这个类在classpath中存在 才会实例化一个对象 //当设置hello=enabled的情况下,如果没有设置则默认为true,即条件符合 @ConditionalOnProperty(prefix="hello", value="enabled", matchIfMissing = true) public class HelloAutoConfiguration { @Autowired private HelloProperties helloProperties; @Bean//使用java配置方式配置这个类 @ConditionalOnMissingBean(Hello.class)//容器中如果没有Hello这个类实例,那么自动配置这个Hello public Hello hello() { Hello hello = new Hello(); hello.setMsg(helloProperties.getMsg()); return hello; } }
并且要添加spring.factories
# Auto Configure org.springframework.boot.autoconfigure.EnableAutoConfiguration=\ com.ibigsea.spring_boot_starter_hello.HelloAutoConfiguration
整个项目结构
好了,到这里我们就完成了一个starter项目了,下面自己测试下
Pom.xml
<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.ibigsea</groupId> <artifactId>test-starter</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>test-starter</name> <url>http://maven.apache.org</url> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <boot.version>1.3.3.RELEASE</boot.version> </properties> <dependencies> <dependency> <groupId>com.ibigsea</groupId> <artifactId>spring-boot-starter-hello</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> <version>${boot.version}</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <version>${boot.version}</version> <scope>test</scope> </dependency> </dependencies> </project>
App.java
package com.ibigsea.test_starter; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import com.ibigsea.spring_boot_starter_hello.Hello; @SpringBootApplication @RestController public class App { @Autowired private Hello hello; @RequestMapping("/") public String index() { return hello.sayHello(); } public static void main(String[] args) { SpringApplication.run(App.class, args); } }
转自: https://blog.csdn.net/a67474506/article/details/52013634