SpringBoot运行原理
1、查看当前项目已启用和未启用自动配置
在application.properties中设置属性
debug=true
2、自动配置满足两个条件 ①配置参数
②配置Bean
3、自己写一个自动配置 ①新建一个Maven项目
文章图片
image
②pom.xml
4.0.0 com.example.springboot
09-springboot-autoconfig
0.0.1-SNAPSHOT 09-springboot-autoconfig http://www.example.com 【SpringBoot运行原理】UTF-8
1.7
1.7
org.springframework.boot
spring-boot-autoconfigure
2.1.3.RELEASE
junit
junit
4.12
test
maven-clean-plugin
3.1.0
maven-resources-plugin
3.0.2
maven-compiler-plugin
3.8.0
maven-surefire-plugin
2.22.1
maven-jar-plugin
3.0.2
maven-install-plugin
2.5.2
maven-deploy-plugin
2.8.2
maven-site-plugin
3.7.1
maven-project-info-reports-plugin
3.0.0
③属性配置
package com.example.springboot;
import org.springframework.boot.context.properties.ConfigurationProperties;
@ConfigurationProperties(prefix = "hello")
public class HelloServiceProperties1 {
private static final String MSG = "world";
private String msg = MSG;
public String getMsg() {
return msg;
}public void setMsg(String msg) {
this.msg = msg;
}
}④判断依据类
package com.example.springboot;
public class HelloService {
private String msg;
public String sayHello() {
return "Hello" + msg;
}
public String getMsg() {
return msg;
}public void setMsg(String msg) {
this.msg = msg;
}
}
⑤自动配置类
package com.example.springboot;
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(HelloServiceProperties1.class)
@ConditionalOnClass(HelloService.class)
@ConditionalOnProperty(prefix = "hello",value = "https://www.it610.com/article/enabled",matchIfMissing = true)
public class HelloServiceAutoConfiguration {@Autowired
private HelloServiceProperties1 helloServiceProperties;
@Bean
@ConditionalOnMissingBean(HelloService.class)
public HelloService helloService() {
HelloService helloService = new HelloService() ;
helloService.setMsg(helloServiceProperties.getMsg());
return helloService;
}
}⑥自动配置
在src/main/resources新建META-INF/spring.factories
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
com.example.springboot.HelloServiceAutoConfiguration
若有多个配置，用“，”隔开
⑦新建springboot项目，在pom.xml添加依赖
com.example.springboot
09-springboot-autoconfig
0.0.1-SNAPSHOT
运行代码
@Autowired
HelloService helloService;
@RequestMapping("/index1")
publicString index1() {
return helloService.sayHello();
}
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