springboot实现自定义自动装配
实现方法
- 激活自动装配 - @EnableAutoConfiguration
- 实现自动装配 - XXXAutoConfiguration
- 配置自动装配实现 - META-INF/spring.factories
1、Springboot服务引导类
@EnableAutoConfiguration
public class MyAutoConfigruationBootStrap {
public static void main(String[] args) {
ConfigurableApplicationContext context = new SpringApplicationBuilder(MyAutoConfigruationBootStrap.class)
.web(WebApplicationType.NONE) //不开启web模式
.run(args);
String helloWorld = context.getBean("HelloWorld", String.class);
System.err.println("获取到了bean对象====="+helloWorld);
//关闭容器
context.close();
}
}
2、HelloWorldAutoConfiguration 自动装配类
@Configuration //模式注解表示配置类
@EnableHelloWord //激活helloworld装配
@MyCondition(name = "userName",value = "xiao") //条件装配，满足条件才会激活HelloWord模块
public class HelloWorldAutoConfiguration {
}
3、 META-INF/spring.factories
# 实现自动装配 org.springframework.boot.autoconfigure.EnableAutoConfiguration= com.zixue.springboottest.configration.HelloWorldAutoConfiguration
4、定义条件装配，及具体规则
@Target({
ElementType.TYPE, ElementType.METHOD })
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Conditional(MyPropertiesCondition.class)
public @interface MyCondition {
/** 属性名称*/
String name();
/** 属性名称*/
String value();
}
public class MyPropertiesCondition implements Condition {
@Override
public boolean matches(ConditionContext conditionContext, AnnotatedTypeMetadata annotatedTypeMetadata) {
// annotatedTypeMetadata 源信息可以获取 MyCondition注解的属性数据
Map<String, Object> attributes = annotatedTypeMetadata.getAnnotationAttributes(MyCondition.class.getName());
if ("userName".equals(attributes.get("name")) && "xiao".equals(attributes.get("value"))){
return true;
}
return false;
}
}
5、激活helloworld模块装配，通过ImportSelector 注入bean
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@AutoConfigurationPackage
@Import(MyImportSelector.class)
public @interface EnableHelloWord {
}
public class MyImportSelector implements ImportSelector {
@Override
public String[] selectImports(AnnotationMetadata annotationMetadata) {
System.err.println("--------运行了自定义的MyImportSelector -----------");
return new String[]{
HelloWordConfiguration.class.getName()};
}
}
@Configuration
public class HelloWordConfiguration {
@Bean
public String HelloWorld(){
return "Hello world 2020.............";
}
}
6、运行结果
. ____ _ __ _ _
/\ / ____ __ _ _(_)_ __ __ _
( ( )\___ | _ | _| | _ / _` |
\/ ___)| |_)| | | | | || (_| | ) ) ) )
|____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.4.0)
2020-11-26 15:22:12.446 INFO 10600 --- [ main] c.z.s.b.MyAutoConfigruationBootStrap : Starting MyAutoConfigruationBootStrap using Java 1.8.0_144 on DESKTOP-JS1AHB8 with PID 10600 (D:springBootProjectspringbootTest argetclasses started by xiao in D:springBootProjectspringbootTest)
2020-11-26 15:22:12.452 INFO 10600 --- [ main] c.z.s.b.MyAutoConfigruationBootStrap : No active profile set, falling back to default profiles: default
--------运行了自定义的MyImportSelector -----------
2020-11-26 15:22:13.984 INFO 10600 --- [ main] c.z.s.b.MyAutoConfigruationBootStrap : Started MyAutoConfigruationBootStrap in 2.404 seconds (JVM running for 4.762)
获取到了bean对象=====Hello world 2020.............