SpringBoot server.port配置原理详解

目录

• SpringBoot server.port配置原理
• 1. autoConfigure
• 2. embed tomcat如何使用
• 小结一下
• server.port不起作用

SpringBoot server.port配置原理

我们经常配置server.port=xxx，但其实这是一个比较复杂的过程才生效的，这次讲讲生效的过程。

1. autoConfigure

本质来源于自动配置

org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryConfiguration

• TomcatServletWebServerFactory

为什么是这个类，核心是beanPostProcess原理

@ConfigurationProperties(prefix = "server", ignoreUnknownFields = true)
public class ServerProperties {
	/**
	 * Server HTTP port.
	 */
	private Integer port;

• beanPostProcess

public class WebServerFactoryCustomizerBeanPostProcessor implements BeanPostProcessor, BeanFactoryAware {
 private ListableBeanFactory beanFactory;
 private List<WebServerFactoryCustomizer<?>> customizers; 

 @Override
 public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
  if (bean instanceof WebServerFactory) {
   postProcessBeforeInitialization((WebServerFactory) bean);
  }
  return bean;
 } 

 @SuppressWarnings("unchecked")
 private void postProcessBeforeInitialization(WebServerFactory webServerFactory) {
  LambdaSafe.callbacks(WebServerFactoryCustomizer.class, getCustomizers(), webServerFactory)
    .withLogger(WebServerFactoryCustomizerBeanPostProcessor.class)
    .invoke((customizer) -> customizer.customize(webServerFactory));
 }

    private Collection<WebServerFactoryCustomizer<?>> getCustomizers() {
  if (this.customizers == null) {
   // Look up does not include the parent context
   this.customizers = new ArrayList<>(getWebServerFactoryCustomizerBeans());
   this.customizers.sort(AnnotationAwareOrderComparator.INSTANCE);
   this.customizers = Collections.unmodifiableList(this.customizers);
  }
  return this.customizers;
 }

 @SuppressWarnings({ "unchecked", "rawtypes" })
 private Collection<WebServerFactoryCustomizer<?>> getWebServerFactoryCustomizerBeans() {
  return (Collection) this.beanFactory.getBeansOfType(WebServerFactoryCustomizer.class, false, false).values();
 }

最终

beanFactory.getBeansOfType(WebServerFactoryCustomizer.class, false, false).values()

WebServerFactoryCustomizer对象.customize(webServerFactory)

@Configuration
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE)
@ConditionalOnClass(ServletRequest.class)
@ConditionalOnWebApplication(type = Type.SERVLET)
@EnableConfigurationProperties(ServerProperties.class)
@Import({ ServletWebServerFactoryAutoConfiguration.BeanPostProcessorsRegistrar.class,
  ServletWebServerFactoryConfiguration.EmbeddedTomcat.class,
  ServletWebServerFactoryConfiguration.EmbeddedJetty.class,
  ServletWebServerFactoryConfiguration.EmbeddedUndertow.class })
public class ServletWebServerFactoryAutoConfiguration {

 @Bean
 public ServletWebServerFactoryCustomizer servletWebServerFactoryCustomizer(ServerProperties serverProperties) {
  return new ServletWebServerFactoryCustomizer(serverProperties);
 }

这里就将port设置好了。

这里使用函数式编程，lambda表达式，将port的值设置进了

ConfigurableServletWebServerFactory ，即TomcatServletWebServerFactory对象

2. embed tomcat如何使用

tomcat创建时，会通过getBean方式获取工厂

就是 TomcatServletWebServerFactory

然后设置connector，从TomcatServletWebServerFactory读取port，设置connector，设置结束

小结一下

Spring Boot在解耦的时候绕了很多弯，先@Bean factory对象，然后BeanPostProcess，然后启动embed tomcat 在factory 中new Tomcat 然后设置Connector，设置port。

server.port不起作用

启动项目报错：

org.apache.catalina.LifecycleException: Protocol handler start failed

怀疑可能端口号冲突，在 application.properties 添加 server.port=8080 未生效

立刻百度一圈没找到答案（感觉可能自己犯的错误太低级），突然想起可能是环境配置里面的配置给覆盖了

#读取环境配置dev(开发)/pro(生产)/test(测试)
spring.profiles.active=dev

找到 application-dev.properties、application-prod.properties 发现果然存在

按照配置的 dev 找到 application-dev.properties 修改 server.port=8080启动生效

以上为个人经验，希望能给大家一个参考，也希望大家多多支持我们。