首页 > 其他分享 >Spring Boot 自动配置原理

Spring Boot 自动配置原理

时间:2024-07-23 22:32:47浏览次数:14  
标签:Spring boot Boot springframework autoconfigure import org 原理 class

Author: ACatSmiling

Since: 2024-07-23

核心场景启动器

Spring Boot 的每个场景启动器都引入了一个spring-boot-starter,这是 Spring Boot 的核心场景启动器。

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter</artifactId>
</dependency>

本文代码基于 Spring Boot 3.2.4 版本。

在 spring-boot-starter 中,又引入了spring-boot-autoconfigure包,spring-boot-autoconfigure 里面事先定义了所有场景的所有配置,只要这个包下的所有类都能生效,那么相当于 Spring Boot 官方写好的整合功能就生效了。

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-autoconfigure</artifactId>
</dependency>

但是 Spring Boot 默认只扫描主程序所在的包,因此扫描不到 spring-boot-autoconfigure 下定义好的所有配置类,这部分的工作,是由@EnableAutoConfiguration注解完成的。

引导加载自动配置类

主程序:

@SpringBootApplication
public class MainApplication {
    public static void main(String[] args) {
        SpringApplication.run(MainApplication.class, args);
    }
}

@SpringBootApplication

@SpringBootApplication

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@SpringBootConfiguration
@EnableAutoConfiguration
@ComponentScan(excludeFilters = { @Filter(type = FilterType.CUSTOM, classes = TypeExcludeFilter.class),
		@Filter(type = FilterType.CUSTOM, classes = AutoConfigurationExcludeFilter.class) })
public @interface SpringBootApplication {
}

@SpringBootConfiguration

@SpringBootConfiguration:是@Configuration的派生注解,表明当前主类实际上也是一个配置类。

@ComponentScan

@ComponentScan:指定扫描的包,默认为当前主类所在包及其子包。

@EnableAutoConfiguration

@EnableAutoConfiguration

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@AutoConfigurationPackage
@Import(AutoConfigurationImportSelector.class)
public @interface EnableAutoConfiguration {
}
@AutoConfigurationPackage

@AutoConfigurationPackage

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@Import(AutoConfigurationPackages.Registrar.class)
public @interface AutoConfigurationPackage {
}
@Import(AutoConfigurationPackages.Registrar.class)

向容器中注册了一个 AutoConfigurationPackages.Registrar.class 组件:

/**
 * {@link ImportBeanDefinitionRegistrar} to store the base package from the importing
 * configuration.
 */
static class Registrar implements ImportBeanDefinitionRegistrar, DeterminableImports {

    @Override
    public void registerBeanDefinitions(AnnotationMetadata metadata, BeanDefinitionRegistry registry) {
       register(registry, new PackageImports(metadata).getPackageNames().toArray(new String[0]));
    }

    @Override
    public Set<Object> determineImports(AnnotationMetadata metadata) {
       return Collections.singleton(new PackageImports(metadata));
    }

}
  • new PackageImports(metadata).getPackageNames():拿到元注解所包含的包信息,实际上就是主类所在的包,如 cn.zero.cloud.business。
  • register()的功能,也就是将主类所在包下的所有组件,批量注册到容器中,这也就是默认包路径为主类所在包的原因。
@Import(AutoConfigurationImportSelector.class)

向容器中注册了一个 AutoConfigurationImportSelector.class 组件,执行如下方法:

@Override
public String[] selectImports(AnnotationMetadata annotationMetadata) {
    if (!isEnabled(annotationMetadata)) {
       return NO_IMPORTS;
    }
    AutoConfigurationEntry autoConfigurationEntry = getAutoConfigurationEntry(annotationMetadata);
    return StringUtils.toStringArray(autoConfigurationEntry.getConfigurations());
}

执行getAutoConfigurationEntry(annotationMetadata)方法,向容器中批量注册一些组件:

/**
 * Return the {@link AutoConfigurationEntry} based on the {@link AnnotationMetadata}
 * of the importing {@link Configuration @Configuration} class.
 * @param annotationMetadata the annotation metadata of the configuration class
 * @return the auto-configurations that should be imported
 */
protected AutoConfigurationEntry getAutoConfigurationEntry(AnnotationMetadata annotationMetadata) {
    if (!isEnabled(annotationMetadata)) {
       return EMPTY_ENTRY;
    }
    AnnotationAttributes attributes = getAttributes(annotationMetadata);
    List<String> configurations = getCandidateConfigurations(annotationMetadata, attributes);
    configurations = removeDuplicates(configurations);
    Set<String> exclusions = getExclusions(annotationMetadata, attributes);
    checkExcludedClasses(configurations, exclusions);
    configurations.removeAll(exclusions);
    configurations = getConfigurationClassFilter().filter(configurations);
    fireAutoConfigurationImportEvents(configurations, exclusions);
    return new AutoConfigurationEntry(configurations, exclusions);
}

执行getCandidateConfigurations(annotationMetadata, attributes)方法:

/**
 * Return the auto-configuration class names that should be considered. By default,
 * this method will load candidates using {@link ImportCandidates}.
 * @param metadata the source metadata
 * @param attributes the {@link #getAttributes(AnnotationMetadata) annotation
 * attributes}
 * @return a list of candidate configurations
 */
protected List<String> getCandidateConfigurations(AnnotationMetadata metadata, AnnotationAttributes attributes) {
    List<String> configurations = ImportCandidates.load(AutoConfiguration.class, getBeanClassLoader())
       .getCandidates();
    // 从类路径下获取预先定义的组件,Spring Boot 2 中此文件名为 spring.factories
    Assert.notEmpty(configurations,
          "No auto configuration classes found in "
                + "META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports. If you "
                + "are using a custom packaging, make sure that file is correct.");
    return configurations;
}

Spring Boot 3 中,事先定义的组件位于 spring-boot-autoconfigure 包类路径下的META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports文件,在 Spring Boot 2 中,对应的文件名是 spring.factories。

protected List<String> getCandidateConfigurations(AnnotationMetadata metadata, AnnotationAttributes attributes) {
  List<String> configurations = SpringFactoriesLoader.loadFactoryNames(getSpringFactoriesLoaderFactoryClass(),
        getBeanClassLoader());
  Assert.notEmpty(configurations, "No auto configuration classes found in META-INF/spring.factories. If you "
        + "are using a custom packaging, make sure that file is correct.");
  return configurations;
}

执行ImportCandidates.load(AutoConfiguration.class, getBeanClassLoader())方法,获取类路径下配置文件中事先定义的,所有待批量注册的组件(配置类):

/**
 * Loads the names of import candidates from the classpath.
 *
 * The names of the import candidates are stored in files named
 * {@code META-INF/spring/full-qualified-annotation-name.imports} on the classpath.
 * Every line contains the full qualified name of the candidate class. Comments are
 * supported using the # character.
 * @param annotation annotation to load
 * @param classLoader class loader to use for loading
 * @return list of names of annotated classes
 */
public static ImportCandidates load(Class<?> annotation, ClassLoader classLoader) {
    Assert.notNull(annotation, "'annotation' must not be null");
    ClassLoader classLoaderToUse = decideClassloader(classLoader);
    String location = String.format(LOCATION, annotation.getName());
    Enumeration<URL> urls = findUrlsInClasspath(classLoaderToUse, location);
    List<String> importCandidates = new ArrayList<>();
    while (urls.hasMoreElements()) {
       URL url = urls.nextElement();
       // 获取配置文件中的预定义组件的全路径
       importCandidates.addAll(readCandidateConfigurations(url));
    }
    return new ImportCandidates(importCandidates);
}
image-20240723221554851

按需开启自动配置项

在上面的分析中,Spring Boot 在启动时,默认会加载 152 个自动配置的组件。但在实际启动时,各 xxxxAutoConfiguration 组件,会根据@Conditional注解,即按照条件装配规则,实现按需配置。我们选取如下几个组件进行分析。

AopAutoConfiguration

org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,其装配规则如下:

package org.springframework.boot.autoconfigure.aop;

import org.aspectj.weaver.Advice;

import org.springframework.aop.config.AopConfigUtils;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.boot.autoconfigure.AutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.EnableAspectJAutoProxy;

/**
 * {@link org.springframework.boot.autoconfigure.EnableAutoConfiguration
 * Auto-configuration} for Spring's AOP support. Equivalent to enabling
 * {@link EnableAspectJAutoProxy @EnableAspectJAutoProxy} in your configuration.
 * <p>
 * The configuration will not be activated if {@literal spring.aop.auto=false}. The
 * {@literal proxyTargetClass} attribute will be {@literal true}, by default, but can be
 * overridden by specifying {@literal spring.aop.proxy-target-class=false}.
 *
 * @author Dave Syer
 * @author Josh Long
 * @since 1.0.0
 * @see EnableAspectJAutoProxy
 */
@AutoConfiguration
// 当配置文件中配置了 spring.aop.auto 属性,且值为 true 时,AopAutoConfiguration 生效,默认为 true
@ConditionalOnProperty(prefix = "spring.aop", name = "auto", havingValue = "true", matchIfMissing = true)
public class AopAutoConfiguration {

    // 当 org.aspectj.weaver.Advice.class 文件存在时,AspectJAutoProxyingConfiguration 才生效
    @Configuration(proxyBeanMethods = false)
    @ConditionalOnClass(Advice.class)
    static class AspectJAutoProxyingConfiguration {

       @Configuration(proxyBeanMethods = false)
       @EnableAspectJAutoProxy(proxyTargetClass = false)
       @ConditionalOnProperty(prefix = "spring.aop", name = "proxy-target-class", havingValue = "false")
       static class JdkDynamicAutoProxyConfiguration {

       }

       @Configuration(proxyBeanMethods = false)
       @EnableAspectJAutoProxy(proxyTargetClass = true)
       @ConditionalOnProperty(prefix = "spring.aop", name = "proxy-target-class", havingValue = "true",
             matchIfMissing = true)
       static class CglibAutoProxyConfiguration {

       }

    }

    // 当 org.aspectj.weaver.Advice.class 文件不存在,且配置文件中 spring.aop.proxy-target-class 属性值为 true (默认为 true)时,ClassProxyingConfiguration 生效
    @Configuration(proxyBeanMethods = false)
    @ConditionalOnMissingClass("org.aspectj.weaver.Advice")
    @ConditionalOnProperty(prefix = "spring.aop", name = "proxy-target-class", havingValue = "true",
          matchIfMissing = true)
    static class ClassProxyingConfiguration {

       @Bean
       static BeanFactoryPostProcessor forceAutoProxyCreatorToUseClassProxying() {
          return (beanFactory) -> {
             if (beanFactory instanceof BeanDefinitionRegistry registry) {
                AopConfigUtils.registerAutoProxyCreatorIfNecessary(registry);
                AopConfigUtils.forceAutoProxyCreatorToUseClassProxying(registry);
             }
          };
       }

    }

}

可以看出,当导入 spring-boot-starter-aop 依赖时,会注册 AspectJAutoProxyingConfiguration 配置类,否则,注册 ClassProxyingConfiguration 配置类,后者是 Spring Boot 默认的的 AOP 功能。

DispatcherServletAutoConfiguration

org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration,其装配规则如下:

package org.springframework.boot.autoconfigure.web.servlet;

import java.util.Arrays;
import java.util.List;

import jakarta.servlet.MultipartConfigElement;
import jakarta.servlet.ServletRegistration;

import org.springframework.beans.factory.ObjectProvider;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.boot.autoconfigure.AutoConfiguration;
import org.springframework.boot.autoconfigure.AutoConfigureOrder;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionMessage;
import org.springframework.boot.autoconfigure.condition.ConditionMessage.Style;
import org.springframework.boot.autoconfigure.condition.ConditionOutcome;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication.Type;
import org.springframework.boot.autoconfigure.condition.SpringBootCondition;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.core.type.AnnotatedTypeMetadata;
import org.springframework.web.multipart.MultipartResolver;
import org.springframework.web.servlet.DispatcherServlet;

/**
 * {@link EnableAutoConfiguration Auto-configuration} for the Spring
 * {@link DispatcherServlet}. Should work for a standalone application where an embedded
 * web server is already present and also for a deployable application using
 * {@link SpringBootServletInitializer}.
 *
 * @author Phillip Webb
 * @author Dave Syer
 * @author Stephane Nicoll
 * @author Brian Clozel
 * @since 2.0.0
 */
// 当前配置类的配置顺序
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE)
// 在 ServletWebServerFactoryAutoConfiguration 后配置
@AutoConfiguration(after = ServletWebServerFactoryAutoConfiguration.class)
// 当项目是一个原生的 Web Servlet 应用时
@ConditionalOnWebApplication(type = Type.SERVLET)
// 当容器中存在 DispatcherServlet 时
@ConditionalOnClass(DispatcherServlet.class)
public class DispatcherServletAutoConfiguration {

    /**
     * The bean name for a DispatcherServlet that will be mapped to the root URL "/".
     */
    public static final String DEFAULT_DISPATCHER_SERVLET_BEAN_NAME = "dispatcherServlet";

    /**
     * The bean name for a ServletRegistrationBean for the DispatcherServlet "/".
     */
    public static final String DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME = "dispatcherServletRegistration";

    @Configuration(proxyBeanMethods = false)
    @Conditional(DefaultDispatcherServletCondition.class)
    // 当容器中存在 ServletRegistration 时
    @ConditionalOnClass(ServletRegistration.class)
    // 开启 WebMvcProperties 类的配置绑定功能,并注册到容器中
    @EnableConfigurationProperties(WebMvcProperties.class)
    protected static class DispatcherServletConfiguration {

       // 注册 DispatcherServlet 组件到容器中,名字为 dispatcherServlet
       @Bean(name = DEFAULT_DISPATCHER_SERVLET_BEAN_NAME)
       public DispatcherServlet dispatcherServlet(WebMvcProperties webMvcProperties) {
          // 新建了一个 DispatcherServlet 对象
          DispatcherServlet dispatcherServlet = new DispatcherServlet();
          dispatcherServlet.setDispatchOptionsRequest(webMvcProperties.isDispatchOptionsRequest());
          dispatcherServlet.setDispatchTraceRequest(webMvcProperties.isDispatchTraceRequest());
          configureThrowExceptionIfNoHandlerFound(webMvcProperties, dispatcherServlet);
          dispatcherServlet.setPublishEvents(webMvcProperties.isPublishRequestHandledEvents());
          dispatcherServlet.setEnableLoggingRequestDetails(webMvcProperties.isLogRequestDetails());
          return dispatcherServlet;
       }

       @SuppressWarnings({ "deprecation", "removal" })
       private void configureThrowExceptionIfNoHandlerFound(WebMvcProperties webMvcProperties,
             DispatcherServlet dispatcherServlet) {
          dispatcherServlet.setThrowExceptionIfNoHandlerFound(webMvcProperties.isThrowExceptionIfNoHandlerFound());
       }

       // 注册 MultipartResolver 组件到容器中,即文件上传解析器
       @Bean
       // 当容器中存在 MultipartResolver 时
       @ConditionalOnBean(MultipartResolver.class)
       // 当容器中没有 name 为 multipartResolver 的 MultipartResolver 对象时
       @ConditionalOnMissingBean(name = DispatcherServlet.MULTIPART_RESOLVER_BEAN_NAME)
       public MultipartResolver multipartResolver(MultipartResolver resolver) {
          // 当容器中有 MultipartResolver 的对象,resolver 参数会自动绑定该对象
          // 此方法的作用是,防止有些用户配置的文件上传解析器不符合规范:
          // 将用户自己配置的文件上传解析器重新注册给容器,并重命名为 multipartResolver (方法名)
          // (Spring Boot 中的文件上传解析器的名字,就叫 multipartResolver)
          // Detect if the user has created a MultipartResolver but named it incorrectly
          return resolver;
       }

    }
    
    ...
}
  • @ConditionalOnWebApplication(type = Type.SERVLET):Spring Boot 支持两种类型的 Web 应用开发,一种是响应式,一种是原生 Servlet。响应式 Web 开发需要导入spring-boot-starter-webflux依赖,原生 Servlet Web 开发需要导入spring-boot-starter-web依赖。

  • @ConditionalOnClass(DispatcherServlet.class):在主类中可以验证项目中存在 DispatcherServlet 类。

    @SpringBootApplication
    public class MainApplication {
        public static void main(String[] args) {
            ConfigurableApplicationContext run = SpringApplication.run(MainApplication.class, args);
    
            String[] beanNamesForType = run.getBeanNamesForType(DispatcherServlet.class);
            System.out.println(beanNamesForType.length);// 1
        }
    }
    

HttpEncodingAutoConfiguration

org.springframework.boot.autoconfigure.web.servlet.HttpEncodingAutoConfiguration,其装配规则如下:

package org.springframework.boot.autoconfigure.web.servlet;

import org.springframework.boot.autoconfigure.AutoConfiguration;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
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.autoconfigure.condition.ConditionalOnWebApplication;
import org.springframework.boot.autoconfigure.web.ServerProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.boot.web.server.WebServerFactoryCustomizer;
import org.springframework.boot.web.servlet.filter.OrderedCharacterEncodingFilter;
import org.springframework.boot.web.servlet.server.ConfigurableServletWebServerFactory;
import org.springframework.boot.web.servlet.server.Encoding;
import org.springframework.context.annotation.Bean;
import org.springframework.core.Ordered;
import org.springframework.web.filter.CharacterEncodingFilter;

/**
 * {@link EnableAutoConfiguration Auto-configuration} for configuring the encoding to use
 * in web applications.
 *
 * @author Stephane Nicoll
 * @author Brian Clozel
 * @since 2.0.0
 */
@AutoConfiguration
// 开启 ServerProperties 类的配置绑定功能,并注册到容器中
@EnableConfigurationProperties(ServerProperties.class)
// 当项目是一个原生的 Web Servlet 应用时
@ConditionalOnWebApplication(type = ConditionalOnWebApplication.Type.SERVLET)
// 当容器中存在 CharacterEncodingFilter 时
@ConditionalOnClass(CharacterEncodingFilter.class)
// 当配置文件中 server.servlet.encoding 属性值为 enabled (默认为 true) 时
@ConditionalOnProperty(prefix = "server.servlet.encoding", value = "enabled", matchIfMissing = true)
public class HttpEncodingAutoConfiguration {

    private final Encoding properties;

    public HttpEncodingAutoConfiguration(ServerProperties properties) {
       this.properties = properties.getServlet().getEncoding();
    }

    // 向容器中注册一个 CharacterEncodingFilter 组件,此组件就是解决 Spring Boot 收到的请求出现乱码的问题
    @Bean
    // 当容器中没有这个 Bean 时才配置,即用户未配置时,Spring Boot 才主动配置一个
    @ConditionalOnMissingBean
    public CharacterEncodingFilter characterEncodingFilter() {
       CharacterEncodingFilter filter = new OrderedCharacterEncodingFilter();
       filter.setEncoding(this.properties.getCharset().name());
       filter.setForceRequestEncoding(this.properties.shouldForce(Encoding.Type.REQUEST));
       filter.setForceResponseEncoding(this.properties.shouldForce(Encoding.Type.RESPONSE));
       return filter;
    }

    @Bean
    public LocaleCharsetMappingsCustomizer localeCharsetMappingsCustomizer() {
       return new LocaleCharsetMappingsCustomizer(this.properties);
    }

    static class LocaleCharsetMappingsCustomizer
          implements WebServerFactoryCustomizer<ConfigurableServletWebServerFactory>, Ordered {

       private final Encoding properties;

       LocaleCharsetMappingsCustomizer(Encoding properties) {
          this.properties = properties;
       }

       @Override
       public void customize(ConfigurableServletWebServerFactory factory) {
          if (this.properties.getMapping() != null) {
             factory.setLocaleCharsetMappings(this.properties.getMapping());
          }
       }

       @Override
       public int getOrder() {
          return 0;
       }

    }

}

HttpEncodingAutoConfiguration 配置类,可以防止 Spring Boot 乱码。

修改默认配置

一般来说,Spring Boot 默认会在底层配好所有需要的组件,但是如果用户自己配置了,就会以用户配置的优先。

以 CharacterEncodingFilter 为例,如果用户希望按自己的需求进行配置,可以在配置类中自行添加:

@Configuration
public class MyConfig {
    @Bean
    public CharacterEncodingFilter characterEncodingFilter() {
        // filter的实现代码
    }
}

从前面对 HttpEncodingAutoConfiguration 的分析可以看出,当用户自己配置了 CharacterEncodingFilter 的实例时,Spring Boot 就不会再配置。

当然,也可以根据组件 @ConfigurationProperties 注解绑定的属性,按需做相应的修改。

总结

Spring Boot 先加载所有默认的自动配置类,即 xxxxxAutoConfiguration.class,每个自动配置类按照条件进行生效。xxxxxAutoConfiguration.class 在配置时,会从对应的 xxxxxProperties.class 中取值,而 xxxxxProperties.class 会和配置文件中对应的值进行绑定(@EnableConfigurationProperties 注解)。

  • 生效的配置类,会给容器中装配很多不同功能的组件。
  • 这些组件装配到容器中后,项目就具有了该组件所具有的功能。
  • 如果用户自行配置了某一个组件,则以用户配置的优先。

若想实现定制化配置,有两种方法:

  • 方法一:用户自行配置组件,添加@Bean注解,用以替换 Spring Boot 底层的默认组件。
  • 方法二:用户查看该组件从配置文件种获取的是什么属性的值,然后按需求自行修改对应的属性值。比如 HttpEncodingAutoConfiguration 对应的就是配置文件中的server.servlet.encoding属性。

更多配置项取值,参考:https://docs.spring.io/spring-boot/docs/current/reference/html/application-properties.html#application-properties

自动配置过程:xxxxxAutoConfiguration.class ---> 注册组件 ---> 从 xxxxxProperties.class 里面拿值 ----> 绑定 application.properties 文件。可以看出,一般通过修改 application.properties 文件中相应的配置,就可完成 Spring Boot 功能的修改。

原文链接

https://github.com/ACatSmiling/zero-to-zero/blob/main/SpringEcosystem/spring-boot.md

标签:Spring,boot,Boot,springframework,autoconfigure,import,org,原理,class
From: https://www.cnblogs.com/acatsmiling/p/18319771

相关文章

  • 人工智能与机器学习原理精解【3】
    文章目录泰勒级数逼近基础海森矩阵一、定义与性质一、定义二、性质三、应用四、结论一阶导数和二阶导数的几何意义一阶导数的几何意义二阶导数的几何意义应用示例导数与微分的区别1.定义与本质2.几何意义3.表达式与关系4.应用场景可微函数定义几何意义性质例子导......
  • 概率论原理精解【4】
    文章目录度量空间概述理论基础定义特点高级概念广泛应用性质例子应用柯西数列柯西数列的定义柯西数列的例子参考文献度量空间概述设f:......
  • springboot学习笔记 1 - Spring Boot 简介
    SpringBoot学习笔记什么是SpringBootSpringBoot的特点SpringBoot与Spring的区别开发环境要求使用SpringInitializr创建项目构建并运行第一个SpringBoot应用代码示例总结什么是SpringBoot大家好,欢迎来到“SpringBoot学习笔记”系列。首先,让我们从一个简单......
  • springboot 使用 rocketMQ
    POM依赖<dependency><groupId>org.apache.rocketmq</groupId><artifactId>rocketmq-spring-boot-starter</artifactId><version>2.2.2</version></dependency>配置文件rocketmq:name-server:192.168.20......
  • 使用Spring Boot构建高性能企业级应用
    使用SpringBoot构建高性能企业级应用大家好,我是微赚淘客系统3.0的小编,是个冬天不穿秋裤,天冷也要风度的程序猿!今天我们将探讨如何使用SpringBoot构建高性能企业级应用,从框架配置到性能优化,全方位提升你的应用性能。一、SpringBoot概述SpringBoot是基于Spring框架的一个快速......
  • 计算机编程—IT实战课堂 Springboot 电竞兴趣论坛系统
    计算机编程—IT实战课堂:Springboot电竞兴趣论坛系统随着电子竞技行业的迅猛发展,电竞爱好者对于交流平台的需求日益增长。结合IT实战课堂的教学实践,我们利用SpringBoot框架开发了一款集讨论、资源共享、赛事追踪于一体的电竞兴趣论坛系统。本文将深入探讨该项目的构思背景、......
  • 创建SpringBoot项目时出现Cannot resolve plugin org.springframework的解决方法 原
    创建SpringBoot项目时出现Cannotresolvepluginorg.springframework的解决方法原因是添加依赖时未添加版本号原因是添加依赖时未添加版本号解决方法:在pom.xml文件中的依赖添加版本号原来:<plugin><groupId>org.springframework.boot</groupId><a......
  • Aquila优化算法(基本原理+matlab源代码)—— 基于Aquila Optimizer原始论文分析
    Matlab源代码位于:AquilaOptimizer:Ameta-heuristicoptimizationalgorithm-FileExchange-MATLABCentral(mathworks.cn)1Aquila优化算法AO是一种基于种群优化方法,受启发于Aquila捕获猎物的方式。Aquila捕获猎物的方式主要有四种:(1)有垂直弯曲的高空翱翔(2)用短......
  • Spring Boot 如何引入redis并实际运用
    1.增加依赖<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId></dependency>2.程序入口初始化Beanimportorg.springframework.w......
  • Spring | BeanFactory与ApplicationContext的关系
    BeanFactory是Spring的早期接口,称为Spring的Bean工厂,ApplicationContext是后期更高级接口,称之为Spring容器ApplicationContext在BeanFactory基础上对功能进行了扩展,例如:监听功能、国际化功能等。BeanFactory的API更偏向底层,ApplicationContext的API大多数是对这些底层API的封装......