10. Springboot的核心配置

Springboot不推荐使用xml配置，推荐使用JavaConfig的形式配置，@Configuration,@Bean

10.1 常用注解

注解@Configuration 通过该注解来表明该类是一个Spring的配置，相当于一个xml文件
注解@Bean 作用于方法上，相当于xml配置中的<bean>

java

package com.neuedu.config.configuration;


import com.neuedu.config.service.UserService;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class AppConfig {


    @Bean("userService")  //<Bean >
    public UserService getUserService(){

        return new UserService();
    }
    
}

注解@ComponentScan 配置扫描包通过该注解自动收集所有的Spring组件，包括 @Configuration 类 basePackages,指定扫描的基准包，其中包含基包和它的子包

java

package com.neuedu.config;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;

@SpringBootApplication(scanBasePackages={
        "com.neuedu",
        "com.neuedu.config"
})
//@ComponentScan
public class App02 {
    public static void main(String[] args) {
        SpringApplication.run(App02.class, args);
    }
}

10.2 读取默认的配置文件

读取application.yml/properties默认配置文件，在Bean中声明属性，在属性上编写@Value注解

java

package com.neuedu.config.configuration;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Configuration;

import java.util.ResourceBundle;

/**
 * server:
 *   port: 80
 * #  servlet:
 * #    context-path: /
 * spring:
 *   application:
 *     name: MyConfig
 *
 * neuedu:
 *   datasource:
 *     user: root
 *     password: 123456
 */
@Configuration
public class YmlConfig {

    @Value("${spring.application.name}")
    private String appName;

    @Value("${server.port}")
    private Integer  serverPort;

    @Value("${neuedu.datasource.user}")
    private String dataUserName;

    @Value("${neuedu.datasource.password}")
    private String dataPassword;


    public String getAppName() {
        return appName;
    }

    public void setAppName(String appName) {
        this.appName = appName;
    }

    public Integer getServerPort() {
        return serverPort;
    }

    public void setServerPort(Integer serverPort) {
        this.serverPort = serverPort;
    }

    public String getDataUserName() {
        return dataUserName;
    }

    public void setDataUserName(String dataUserName) {
        this.dataUserName = dataUserName;
    }

    public String getDataPassword() {
        return dataPassword;
    }

    public void setDataPassword(String dataPassword) {
        this.dataPassword = dataPassword;
    }
}

10.3. 读取外部的属性配置文件

创建jdbc.properties

properties

jdbc.url=jdbc:mysql://localhost:3306/mybatis jdbc.name=root jdbc.password=root

创建配置类 @Configuration
在配置类上声明 @PropertySource(value="classpath:jdbc.properties")注解
- value属性表明，读取的
- 如果配置文件不存在，则默认报错，可以添加ignoreResourceNotFound属性（true）,忽略掉找不到的资源
在配置类中声明属性，使用@Value注解读取配置文件中的内容

java

package com.neuedu.config.configuration;


import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;

@Configuration
@PropertySource(value="classpath:jdbc.properties")
public class OtherConfigFile {

    @Value("${jdbc.url}")
    private String url;

    @Bean("url")
    String getUrl(){
        System.out.println("url = " + url);
        return url;
    }
   
}

10.4. 导入其他配置

@Import 注解，导入其他配置类

@Import(SysConfig.class)

@ImportResources 注解，导入其他配置文件xml类型的

@ImportResource("classpath:springmvc.xml")

@ComponentScan 扫描组件的（Controller、servce、Configuration）

10.5. 自动配置

执行main为什么就能启动Tomcat?

10.5.1. 代码跟踪

main
SpringApplication.run(App03.class,args);
在SpringApplication 的 1301 public static ConfigurableApplicationContext run(Class<?> primarySource, String... args) {
在SpringApplication 的 1312 行 public static ConfigurableApplicationContext run(Class<?>[] primarySources, String[] args) {`
在SpringApplication 的 263 public SpringApplication(Class<?>... primarySources) {
在SpringApplication 的 278行 public SpringApplication(ResourceLoader resourceLoader, Class<?>... primarySources) {
- 283行 this.bootstrappers = new ArrayList<>(getSpringFactoriesInstances(Bootstrapper.class));
- 在SpringApplication 的 445行 private <T> Collection<T> getSpringFactoriesInstances(Class<T> type, Class<?>[] parameterTypes, Object... args) {
- 448行： Set<String> names = new LinkedHashSet<>(SpringFactoriesLoader.loadFactoryNames(type, classLoader));
SpringFactoriesLoader 132行 ·return loadSpringFactories(classLoaderToUse).getOrDefault(factoryTypeName, Collections.emptyList());·
classLoader.getResources(FACTORIES_RESOURCE_LOCATION); 读取所有的 META-INF/spring.factories 所有jar、包下的

java

private static Map<String, List<String>> loadSpringFactories(ClassLoader classLoader) {
   Map<String, List<String>> result = cache.get(classLoader);
   if (result != null) {
      return result;
   }

   result = new HashMap<>();
   try {
      Enumeration<URL> urls = classLoader.getResources(FACTORIES_RESOURCE_LOCATION);
      while (urls.hasMoreElements()) {
         URL url = urls.nextElement();
         UrlResource resource = new UrlResource(url);
         Properties properties = PropertiesLoaderUtils.loadProperties(resource);
         for (Map.Entry<?, ?> entry : properties.entrySet()) {
            String factoryTypeName = ((String) entry.getKey()).trim();
            String[] factoryImplementationNames =
                  StringUtils.commaDelimitedListToStringArray((String) entry.getValue());
            for (String factoryImplementationName : factoryImplementationNames) {
               result.computeIfAbsent(factoryTypeName, key -> new ArrayList<>())
                     .add(factoryImplementationName.trim());
            }
         }
      }

      // Replace all lists with unmodifiable lists containing unique elements
      result.replaceAll((factoryType, implementations) -> implementations.stream().distinct()
            .collect(Collectors.collectingAndThen(Collectors.toList(), Collections::unmodifiableList)));
      cache.put(classLoader, result);
   }
   catch (IOException ex) {
      throw new IllegalArgumentException("Unable to load factories from location [" +
            FACTORIES_RESOURCE_LOCATION + "]", ex);
   }
   return result;
}

在Spring-boot-autoconfiger 的jar中加载自动配置类 EnableAutoConfiguration

properties

# Initializers
org.springframework.context.ApplicationContextInitializer=\
org.springframework.boot.autoconfigure.SharedMetadataReaderFactoryContextInitializer,\
org.springframework.boot.autoconfigure.logging.ConditionEvaluationReportLoggingListener

# Application Listeners
org.springframework.context.ApplicationListener=\
org.springframework.boot.autoconfigure.BackgroundPreinitializer

# Auto Configuration Import Listeners
org.springframework.boot.autoconfigure.AutoConfigurationImportListener=\
org.springframework.boot.autoconfigure.condition.ConditionEvaluationReportAutoConfigurationImportListener

# Auto Configuration Import Filters
org.springframework.boot.autoconfigure.AutoConfigurationImportFilter=\
org.springframework.boot.autoconfigure.condition.OnBeanCondition,\
org.springframework.boot.autoconfigure.condition.OnClassCondition,\
org.springframework.boot.autoconfigure.condition.OnWebApplicationCondition

# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration,\
org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,\
org.springframework.boot.autoconfigure.amqp.RabbitAutoConfiguration,\
org.springframework.boot.autoconfigure.batch.BatchAutoConfiguration,\
org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration,\
org.springframework.boot.autoconfigure.cassandra.CassandraAutoConfiguration,\
org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration,\
org.springframework.boot.autoconfigure.context.LifecycleAutoConfiguration,\
org.springframework.boot.autoconfigure.context.MessageSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration,\
org.springframework.boot.autoconfigure.couchbase.CouchbaseAutoConfiguration,\
org.springframework.boot.autoconfigure.dao.PersistenceExceptionTranslationAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraReactiveDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraReactiveRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseReactiveDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseReactiveRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ReactiveElasticsearchRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ReactiveElasticsearchRestClientAutoConfiguration,\
org.springframework.boot.autoconfigure.data.jdbc.JdbcRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.jpa.JpaRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.ldap.LdapRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoReactiveDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoReactiveRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.neo4j.Neo4jDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.neo4j.Neo4jReactiveDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.neo4j.Neo4jReactiveRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.neo4j.Neo4jRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.solr.SolrRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.r2dbc.R2dbcDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.r2dbc.R2dbcRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration,\
org.springframework.boot.autoconfigure.data.redis.RedisReactiveAutoConfiguration,\
org.springframework.boot.autoconfigure.data.redis.RedisRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.rest.RepositoryRestMvcAutoConfiguration,\
org.springframework.boot.autoconfigure.data.web.SpringDataWebAutoConfiguration,\
org.springframework.boot.autoconfigure.elasticsearch.ElasticsearchRestClientAutoConfiguration,\
org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration,\
org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfiguration,\
org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAutoConfiguration,\
org.springframework.boot.autoconfigure.gson.GsonAutoConfiguration,\
org.springframework.boot.autoconfigure.h2.H2ConsoleAutoConfiguration,\
org.springframework.boot.autoconfigure.hateoas.HypermediaAutoConfiguration,\
org.springframework.boot.autoconfigure.hazelcast.HazelcastAutoConfiguration,\
org.springframework.boot.autoconfigure.hazelcast.HazelcastJpaDependencyAutoConfiguration,\
org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration,\
org.springframework.boot.autoconfigure.http.codec.CodecsAutoConfiguration,\
org.springframework.boot.autoconfigure.influx.InfluxDbAutoConfiguration,\
org.springframework.boot.autoconfigure.info.ProjectInfoAutoConfiguration,\
org.springframework.boot.autoconfigure.integration.IntegrationAutoConfiguration,\
org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.JdbcTemplateAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.JndiDataSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.XADataSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.JmsAutoConfiguration,\
org.springframework.boot.autoconfigure.jmx.JmxAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.JndiConnectionFactoryAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.activemq.ActiveMQAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.artemis.ArtemisAutoConfiguration,\
org.springframework.boot.autoconfigure.jersey.JerseyAutoConfiguration,\
org.springframework.boot.autoconfigure.jooq.JooqAutoConfiguration,\
org.springframework.boot.autoconfigure.jsonb.JsonbAutoConfiguration,\
org.springframework.boot.autoconfigure.kafka.KafkaAutoConfiguration,\
org.springframework.boot.autoconfigure.availability.ApplicationAvailabilityAutoConfiguration,\
org.springframework.boot.autoconfigure.ldap.embedded.EmbeddedLdapAutoConfiguration,\
org.springframework.boot.autoconfigure.ldap.LdapAutoConfiguration,\
org.springframework.boot.autoconfigure.liquibase.LiquibaseAutoConfiguration,\
org.springframework.boot.autoconfigure.mail.MailSenderAutoConfiguration,\
org.springframework.boot.autoconfigure.mail.MailSenderValidatorAutoConfiguration,\
org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongoAutoConfiguration,\
org.springframework.boot.autoconfigure.mongo.MongoAutoConfiguration,\
org.springframework.boot.autoconfigure.mongo.MongoReactiveAutoConfiguration,\
org.springframework.boot.autoconfigure.mustache.MustacheAutoConfiguration,\
org.springframework.boot.autoconfigure.neo4j.Neo4jAutoConfiguration,\
org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration,\
org.springframework.boot.autoconfigure.quartz.QuartzAutoConfiguration,\
org.springframework.boot.autoconfigure.r2dbc.R2dbcAutoConfiguration,\
org.springframework.boot.autoconfigure.r2dbc.R2dbcTransactionManagerAutoConfiguration,\
org.springframework.boot.autoconfigure.rsocket.RSocketMessagingAutoConfiguration,\
org.springframework.boot.autoconfigure.rsocket.RSocketRequesterAutoConfiguration,\
org.springframework.boot.autoconfigure.rsocket.RSocketServerAutoConfiguration,\
org.springframework.boot.autoconfigure.rsocket.RSocketStrategiesAutoConfiguration,\
org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.servlet.UserDetailsServiceAutoConfiguration,\
org.springframework.boot.autoconfigure.security.servlet.SecurityFilterAutoConfiguration,\
org.springframework.boot.autoconfigure.security.reactive.ReactiveSecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.reactive.ReactiveUserDetailsServiceAutoConfiguration,\
org.springframework.boot.autoconfigure.security.rsocket.RSocketSecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.saml2.Saml2RelyingPartyAutoConfiguration,\
org.springframework.boot.autoconfigure.sendgrid.SendGridAutoConfiguration,\
org.springframework.boot.autoconfigure.session.SessionAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.client.servlet.OAuth2ClientAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.client.reactive.ReactiveOAuth2ClientAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.resource.servlet.OAuth2ResourceServerAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.resource.reactive.ReactiveOAuth2ResourceServerAutoConfiguration,\
org.springframework.boot.autoconfigure.solr.SolrAutoConfiguration,\
org.springframework.boot.autoconfigure.task.TaskExecutionAutoConfiguration,\
org.springframework.boot.autoconfigure.task.TaskSchedulingAutoConfiguration,\
org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration,\
org.springframework.boot.autoconfigure.transaction.TransactionAutoConfiguration,\
org.springframework.boot.autoconfigure.transaction.jta.JtaAutoConfiguration,\
org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration,\
org.springframework.boot.autoconfigure.web.client.RestTemplateAutoConfiguration,\
org.springframework.boot.autoconfigure.web.embedded.EmbeddedWebServerFactoryCustomizerAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.HttpHandlerAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.ReactiveWebServerFactoryAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.WebFluxAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.error.ErrorWebFluxAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.function.client.ClientHttpConnectorAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.function.client.WebClientAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.HttpEncodingAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.MultipartAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration,\
org.springframework.boot.autoconfigure.websocket.reactive.WebSocketReactiveAutoConfiguration,\
org.springframework.boot.autoconfigure.websocket.servlet.WebSocketServletAutoConfiguration,\
org.springframework.boot.autoconfigure.websocket.servlet.WebSocketMessagingAutoConfiguration,\
org.springframework.boot.autoconfigure.webservices.WebServicesAutoConfiguration,\
org.springframework.boot.autoconfigure.webservices.client.WebServiceTemplateAutoConfiguration

# Failure analyzers
org.springframework.boot.diagnostics.FailureAnalyzer=\
org.springframework.boot.autoconfigure.data.redis.RedisUrlSyntaxFailureAnalyzer,\
org.springframework.boot.autoconfigure.diagnostics.analyzer.NoSuchBeanDefinitionFailureAnalyzer,\
org.springframework.boot.autoconfigure.flyway.FlywayMigrationScriptMissingFailureAnalyzer,\
org.springframework.boot.autoconfigure.jdbc.DataSourceBeanCreationFailureAnalyzer,\
org.springframework.boot.autoconfigure.jdbc.HikariDriverConfigurationFailureAnalyzer,\
org.springframework.boot.autoconfigure.r2dbc.ConnectionFactoryBeanCreationFailureAnalyzer,\
org.springframework.boot.autoconfigure.session.NonUniqueSessionRepositoryFailureAnalyzer

# Template availability providers
org.springframework.boot.autoconfigure.template.TemplateAvailabilityProvider=\
org.springframework.boot.autoconfigure.freemarker.FreeMarkerTemplateAvailabilityProvider,\
org.springframework.boot.autoconfigure.mustache.MustacheTemplateAvailabilityProvider,\
org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAvailabilityProvider,\
org.springframework.boot.autoconfigure.thymeleaf.ThymeleafTemplateAvailabilityProvider,\
org.springframework.boot.autoconfigure.web.servlet.JspTemplateAvailabilityProvider

期中包含 DispatcherServletAutoConfiguration,可以自动配置 DispatcherServlet

java

/*
 * Copyright 2012-2020 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

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

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

import javax.servlet.MultipartConfigElement;
import javax.servlet.ServletRegistration;

import org.springframework.beans.factory.ObjectProvider;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
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
 */
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE)
@Configuration(proxyBeanMethods = false)
@ConditionalOnWebApplication(type = Type.SERVLET)
@ConditionalOnClass(DispatcherServlet.class)
@AutoConfigureAfter(ServletWebServerFactoryAutoConfiguration.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)
	@ConditionalOnClass(ServletRegistration.class)
	@EnableConfigurationProperties(WebMvcProperties.class)
	protected static class DispatcherServletConfiguration {

		@Bean(name = DEFAULT_DISPATCHER_SERVLET_BEAN_NAME)
		public DispatcherServlet dispatcherServlet(WebMvcProperties webMvcProperties) {
			DispatcherServlet dispatcherServlet = new DispatcherServlet();
			dispatcherServlet.setDispatchOptionsRequest(webMvcProperties.isDispatchOptionsRequest());
			dispatcherServlet.setDispatchTraceRequest(webMvcProperties.isDispatchTraceRequest());
			dispatcherServlet.setThrowExceptionIfNoHandlerFound(webMvcProperties.isThrowExceptionIfNoHandlerFound());
			dispatcherServlet.setPublishEvents(webMvcProperties.isPublishRequestHandledEvents());
			dispatcherServlet.setEnableLoggingRequestDetails(webMvcProperties.isLogRequestDetails());
			return dispatcherServlet;
		}

		@Bean
		@ConditionalOnBean(MultipartResolver.class)
		@ConditionalOnMissingBean(name = DispatcherServlet.MULTIPART_RESOLVER_BEAN_NAME)
		public MultipartResolver multipartResolver(MultipartResolver resolver) {
			// Detect if the user has created a MultipartResolver but named it incorrectly
			return resolver;
		}

	}

	@Configuration(proxyBeanMethods = false)
	@Conditional(DispatcherServletRegistrationCondition.class)
	@ConditionalOnClass(ServletRegistration.class)
	@EnableConfigurationProperties(WebMvcProperties.class)
	@Import(DispatcherServletConfiguration.class)
	protected static class DispatcherServletRegistrationConfiguration {

		@Bean(name = DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME)
		@ConditionalOnBean(value = DispatcherServlet.class, name = DEFAULT_DISPATCHER_SERVLET_BEAN_NAME)
		public DispatcherServletRegistrationBean dispatcherServletRegistration(DispatcherServlet dispatcherServlet,
				WebMvcProperties webMvcProperties, ObjectProvider<MultipartConfigElement> multipartConfig) {
			DispatcherServletRegistrationBean registration = new DispatcherServletRegistrationBean(dispatcherServlet,
					webMvcProperties.getServlet().getPath());
			registration.setName(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME);
			registration.setLoadOnStartup(webMvcProperties.getServlet().getLoadOnStartup());
			multipartConfig.ifAvailable(registration::setMultipartConfig);
			return registration;
		}

	}

	@Order(Ordered.LOWEST_PRECEDENCE - 10)
	private static class DefaultDispatcherServletCondition extends SpringBootCondition {

		@Override
		public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata metadata) {
			ConditionMessage.Builder message = ConditionMessage.forCondition("Default DispatcherServlet");
			ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
			List<String> dispatchServletBeans = Arrays
					.asList(beanFactory.getBeanNamesForType(DispatcherServlet.class, false, false));
			if (dispatchServletBeans.contains(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME)) {
				return ConditionOutcome
						.noMatch(message.found("dispatcher servlet bean").items(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME));
			}
			if (beanFactory.containsBean(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME)) {
				return ConditionOutcome.noMatch(
						message.found("non dispatcher servlet bean").items(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME));
			}
			if (dispatchServletBeans.isEmpty()) {
				return ConditionOutcome.match(message.didNotFind("dispatcher servlet beans").atAll());
			}
			return ConditionOutcome.match(message.found("dispatcher servlet bean", "dispatcher servlet beans")
					.items(Style.QUOTE, dispatchServletBeans)
					.append("and none is named " + DEFAULT_DISPATCHER_SERVLET_BEAN_NAME));
		}

	}

	@Order(Ordered.LOWEST_PRECEDENCE - 10)
	private static class DispatcherServletRegistrationCondition extends SpringBootCondition {

		@Override
		public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata metadata) {
			ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
			ConditionOutcome outcome = checkDefaultDispatcherName(beanFactory);
			if (!outcome.isMatch()) {
				return outcome;
			}
			return checkServletRegistration(beanFactory);
		}

		private ConditionOutcome checkDefaultDispatcherName(ConfigurableListableBeanFactory beanFactory) {
			boolean containsDispatcherBean = beanFactory.containsBean(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME);
			if (!containsDispatcherBean) {
				return ConditionOutcome.match();
			}
			List<String> servlets = Arrays
					.asList(beanFactory.getBeanNamesForType(DispatcherServlet.class, false, false));
			if (!servlets.contains(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME)) {
				return ConditionOutcome.noMatch(
						startMessage().found("non dispatcher servlet").items(DEFAULT_DISPATCHER_SERVLET_BEAN_NAME));
			}
			return ConditionOutcome.match();
		}

		private ConditionOutcome checkServletRegistration(ConfigurableListableBeanFactory beanFactory) {
			ConditionMessage.Builder message = startMessage();
			List<String> registrations = Arrays
					.asList(beanFactory.getBeanNamesForType(ServletRegistrationBean.class, false, false));
			boolean containsDispatcherRegistrationBean = beanFactory
					.containsBean(DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME);
			if (registrations.isEmpty()) {
				if (containsDispatcherRegistrationBean) {
					return ConditionOutcome.noMatch(message.found("non servlet registration bean")
							.items(DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME));
				}
				return ConditionOutcome.match(message.didNotFind("servlet registration bean").atAll());
			}
			if (registrations.contains(DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME)) {
				return ConditionOutcome.noMatch(message.found("servlet registration bean")
						.items(DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME));
			}
			if (containsDispatcherRegistrationBean) {
				return ConditionOutcome.noMatch(message.found("non servlet registration bean")
						.items(DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME));
			}
			return ConditionOutcome.match(message.found("servlet registration beans").items(Style.QUOTE, registrations)
					.append("and none is named " + DEFAULT_DISPATCHER_SERVLET_REGISTRATION_BEAN_NAME));
		}

		private ConditionMessage.Builder startMessage() {
			return ConditionMessage.forCondition("DispatcherServlet Registration");
		}

	}

}

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12.5.2 自动配置排除

当pom文档中添加了数据库相关的依赖如

xml

   <!--数据库的相关支持 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <!--mysql驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

那么自动配置类DataSourceAutoConfiguration就会生效,但是此处加载数据库配置属性 driverClass等配置值的时候会出错

properties

***************************
APPLICATION FAILED TO START
***************************

Description:

Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.

Reason: Failed to determine a suitable driver class


Action:

Consider the following:
	If you want an embedded database (H2, HSQL or Derby), please put it on the classpath.
	If you have database settings to be loaded from a particular profile you may need to activate it (no profiles are currently active).

此时可以在yml文件或者Properties文件中定义数据库连接池的信息

yml

spring:
  datasource:
    username: root
    password: root
    url: jdbc:mysql://localhost:3306/his?useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=UTC
    driver-class-name: com.mysql.cj.jdbc.Driver

如果此时不确定链接数据库的信息（即不配置上面的数据源），并还需要jdbc相关的类库，可以在主类的SpringBootApplication注解上提那家exclude属性，排除某一个自动配置类（这里排除数据源配置类DataSourceAutoConfiguration）

@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)

10.5.3. 条件注解

关闭自动配置

在SpirngbootApplication注解中添加exclude属性指定哪些自动配置类，忽略（关闭）

10.6. SpringBootApplication注解

@SpringBootConfiguration 相当于Configuration @EnableAutoConfiguration 自动配置 @ComponentScan 包扫描

10.7. 配置文件

默认的配置文件

application.properties

application.yml 底层会转换成properties文件

默认的属性文件

https://docs.spring.io/spring-boot/docs/2.2.6.RELEASE/reference/html/appendix-application-properties.html#common-application-properties

10.6. SpringBoot日志

常见的日志框架 common-logging、 slf4j、logback 、log4j、log4j2

TRACE、DEBUG、INFO、ERROR、FALT

Springboot默认使用slf4j和logback

默认级别是INFO

通过logger.

slf4j ：面向日志的接口

具体的日志实现:logback

10.6.1. 测试Controller

java

@RestController
public class HelloConfigController {
    Logger logger = LoggerFactory.getLogger(HelloConfigController.class);


    /**
     * http://127.0.0.1/index
     * @return
     */
    @RequestMapping("/index")
    String hello(){
        logger.info("访问RestController");


        return "index";
    }

}

10.6.2. 默认级别

10.6.3. 调整后的级别

12.6.4 使用lombok

使用lombok省略在类中申明log对象

  <!--引入lombok 省略 SLF4j  setter-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

在类上面声明@Slf4j注解

package com.neuedu.boot.controller;

import lombok.extern.slf4j.Slf4j;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * 项目：      springboot
 * 类名:       LogController
 * 创建时间：  2024/3/26 15：33
 * 描述 :
 * 作者 :     张金山
 * QQ :     314649444
 * Site:      https://jshand.gitee.io
 */
@RestController
@Slf4j
public class LogController {
    // Logger log = LoggerFactory.getLogger(LogController.class);   //不在需要

    @RequestMapping("/log")
    public String testLog(){
        log.trace("trace log");
        log.debug("debug log");
        log.info("info log");
        log.warn("warn log");
        log.error("error log");


        return "success";
    }


}

10.7. Profiles

通过profiles切换不同环境的配置文件

Profile是Spring用来针对不同的环境对不同的配置提供支持的，全局Profile配置使用application-{profile}.properties。

通过在application.properties中设置spring.profiles.active=prod来指定活动的Profile。

示例：有两个环境分别为生产(prod)和开发(dev)环境，生产环境下端口号为80，开发环境下端口为8088

JavaSE扩展

10. Springboot的核心配置

10.1 常用注解

10.2 读取默认的配置文件

10.3. 读取外部的属性配置文件

10.4. 导入其他配置

10.5. 自动配置

10.5.1. 代码跟踪

12.5.2 自动配置排除

10.5.3. 条件注解

10.6. SpringBootApplication注解

10.7. 配置文件

10.6. SpringBoot日志

10.6.1. 测试Controller

10.6.2. 默认级别

10.6.3. 调整后的级别

12.6.4 使用lombok

10.7. Profiles

8.7.1. 也可以在虚拟机上配置执行参数

10. Springboot的核心配置 ​

10.1 常用注解 ​

10.2 读取默认的配置文件 ​

10.3. 读取外部的属性配置文件 ​

10.4. 导入其他配置 ​

10.5. 自动配置 ​

10.5.1. 代码跟踪 ​

12.5.2 自动配置排除 ​

10.5.3. 条件注解 ​

10.6. SpringBootApplication注解 ​

10.7. 配置文件 ​

10.6. SpringBoot日志 ​

10.6.1. 测试Controller ​

10.6.2. 默认级别 ​

10.6.3. 调整后的级别 ​

12.6.4 使用lombok ​

10.7. Profiles ​

8.7.1. 也可以在虚拟机上配置执行参数 ​

10. Springboot的核心配置

10.1 常用注解

10.2 读取默认的配置文件

10.3. 读取外部的属性配置文件

10.4. 导入其他配置

10.5. 自动配置

10.5.1. 代码跟踪

12.5.2 自动配置排除

10.5.3. 条件注解

10.6. SpringBootApplication注解

10.7. 配置文件

10.6. SpringBoot日志

10.6.1. 测试Controller

10.6.2. 默认级别

10.6.3. 调整后的级别

12.6.4 使用lombok

10.7. Profiles

8.7.1. 也可以在虚拟机上配置执行参数