Spring Boot自動配置
阿新 • • 發佈：2018-12-13
簡而言之， Spring Boot的自動配置是一個執行時（更準確地說，是應用程式啟動時）的過程，考慮了眾多因素，才決定Spring配置應該用哪個，不該用哪個。舉幾個例子，下面這些情況都是Spring Boot的自動配置要考慮的。
①Spring的JdbcTemplate是不是在Classpath裡？如果是，並且有DataSource的Bean，則自動配置一個JdbcTemplate的Bean。
②Thymeleaf是不是在Classpath裡？如果是，則配置Thymeleaf的模板解析器、檢視解析器以及模板引擎。
③Spring Security是不是在Classpath裡？如果是，則進行一個非常基本的Web安全設定。每當應用程式啟動的時候， Spring Boot的自動配置都要做將近200個這樣的決定，涵蓋安全、整合、持久化、 Web開發等諸多方面。所有這些自動配置就是為了儘量不讓你自己寫配置。有意思的是，自動配置的東西很難寫在書本里。如果不能寫出配置，那又該怎麼描述並討論它們呢？
在嚮應用程式加入Spring Boot時，有個名為spring-boot-autoconfigure的JAR檔案，其中包含了很多配置類。每個配置類都在應用程式的Classpath裡，都有機會為應用程式的配置添磚加瓦。這些配置類裡有用於Thymeleaf的配置，有用於Spring Data JPA的配置，有用於Spiring MVC的配置，還有很多其他東西的配置，你可以自己選擇是否在Spring應用程式裡使用它們。所有這些配置如此與眾不同，原因在於它們利用了Spring的條件化配置，這是Spring 4.0引入的新特性。條件化配置允許配置存在於應用程式中，但在滿足某些特定條件之前都忽略這個配置。在Spring裡可以很方便地編寫你自己的條件，你所要做的就是實現Condition介面，覆蓋它的matches()方法。舉例來說，下面這個簡單的條件類只有在Classpath裡存在JdbcTemplate時才會生效
雖然本例中的條件相當簡單，但Spring Boot定義了很多更有趣的條件，並把它們運用到了配置類上，這些配置類構成了Spring Boot的自動配置。 Spring Boot運用條件化配置的方法是，定義多個特殊的條件化註解，並將它們用到配置類上。表2-1列出了Spring Boot提供的條件化註解。
Spring Boot提供多少自動配置模組(org.springframework.boot.autoconfigure META-INF/spring.factories)
# 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.OnClassCondition # 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.cloud.CloudAutoConfiguration,\ org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration,\ 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.ElasticsearchAutoConfiguration,\ org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchDataAutoConfiguration,\ org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchRepositoriesAutoConfiguration,\ org.springframework.boot.autoconfigure.data.jpa.JpaRepositoriesAutoConfiguration,\ org.springframework.boot.autoconfigure.data.ldap.LdapDataAutoConfiguration,\ 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.Neo4jRepositoriesAutoConfiguration,\ org.springframework.boot.autoconfigure.data.solr.SolrRepositoriesAutoConfiguration,\ 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.jest.JestAutoConfiguration,\ org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration,\ org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfiguration,\ 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.groovy.template.GroovyTemplateAutoConfiguration,\ 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.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.orm.jpa.HibernateJpaAutoConfiguration,\ org.springframework.boot.autoconfigure.quartz.QuartzAutoConfiguration,\ org.springframework.boot.autoconfigure.reactor.core.ReactorCoreAutoConfiguration,\ org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration,\ org.springframework.boot.autoconfigure.security.servlet.SecurityRequestMatcherProviderAutoConfiguration,\ 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.sendgrid.SendGridAutoConfiguration,\ org.springframework.boot.autoconfigure.session.SessionAutoConfiguration,\ org.springframework.boot.autoconfigure.security.oauth2.client.OAuth2ClientAutoConfiguration,\ org.springframework.boot.autoconfigure.solr.SolrAutoConfiguration,\ 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.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 # Failure analyzers org.springframework.boot.diagnostics.FailureAnalyzer=\ org.springframework.boot.autoconfigure.diagnostics.analyzer.NoSuchBeanDefinitionFailureAnalyzer,\ org.springframework.boot.autoconfigure.jdbc.DataSourceBeanCreationFailureAnalyzer,\ org.springframework.boot.autoconfigure.jdbc.HikariDriverConfigurationFailureAnalyzer,\ 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
Spring Boot封裝好的Condition在這裡(org.springframework.boot.autoconfigure.condition)
下面舉個簡單例子來說明
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>vip.fkandy</groupId>
<artifactId>springboot</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>springboot</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.5.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
package vip.fkandy.condition;
import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.core.type.AnnotatedTypeMetadata;
public class GBKCondition implements Condition {
@Override
public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
String encoding = System.getProperty("file.encoding");
if (null != encoding) {
return "gbk".equals(encoding.toLowerCase());
}
return false;
}
}
package vip.fkandy.condition;
import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.core.type.AnnotatedTypeMetadata;
public class UTF8Condition implements Condition {
@Override
public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
String encoding = System.getProperty("file.encoding");
if (null != encoding) {
return "utf-8".equals(encoding.toLowerCase());
}
return false;
}
}
package vip.fkandy.config;
import org.springframework.boot.SpringBootConfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Conditional;
import vip.fkandy.condition.GBKCondition;
import vip.fkandy.condition.UTF8Condition;
import vip.fkandy.convert.EncodingConvert;
import vip.fkandy.convert.GBKEncodingConvert;
import vip.fkandy.convert.UTF8EncodingConvert;
/**
* @Condition 基於條件的配置，一般配合Condition介面一起使用，
* 只有介面的實現類返回true才裝配，否則不裝配
* @author chenjianfei
*/
@SpringBootConfiguration
public class EncodingConvertConfig {
@Bean
@Conditional(GBKCondition.class)
public EncodingConvert createGBKEncodingConvert() {
return new GBKEncodingConvert();
}
@Bean
@Conditional(UTF8Condition.class)
public EncodingConvert createUTF8EncodingConvert() {
return new UTF8EncodingConvert();
}
}
package vip.fkandy.convert;
public interface EncodingConvert {
}
package vip.fkandy.convert;
public class GBKEncodingConvert implements EncodingConvert {
}
package vip.fkandy.convert;
public class UTF8EncodingConvert implements EncodingConvert{
}
package vip.fkandy;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;
import vip.fkandy.convert.EncodingConvert;
/**
* Condition實現介面boolean matches(ConditionContext context, AnnotatedTypeMetadata
* metadata);方法
*
* @Condition 基於條件的配置，一般配合Condition介面一起使用，
* 只有介面的實現類返回true才裝配，否則不裝配；這個註解可以使用在方法上也可以使用在類是哪個
*
*
*
* @author chenjianfei
*
*/
@SpringBootApplication
public class Application {
public static void main(String[] args) {
ConfigurableApplicationContext context = SpringApplication.run(Application.class, args);
System.out.println(context.getBeansOfType(EncodingConvert.class));
}
}
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.0.5.RELEASE)
2018-10-02 09:00:54.686 INFO 12696 --- [ main] vip.fkandy.Application : Starting Application on DESKTOP-6FVEB35 with PID 12696 (C:\eclipse-workspace\00\springboot-1\target\classes started by chenjianfei in C:\eclipse-workspace\00\springboot-1)
2018-10-02 09:00:54.689 INFO 12696 --- [ main] vip.fkandy.Application : No active profile set, falling back to default profiles: default
2018-10-02 09:00:54.730 INFO 12696 --- [ main] ConfigServletWebServerApplicationContext : Refreshing org.springframework.boot.web.ser[email protected]5a955565: startup date [Tue Oct 02 09:00:54 CST 2018]; root of context hierarchy
2018-10-02 09:00:56.078 INFO 12696 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8181 (http)
2018-10-02 09:00:56.093 INFO 12696 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2018-10-02 09:00:56.094 INFO 12696 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/8.5.34
2018-10-02 09:00:56.097 INFO 12696 --- [ost-startStop-1] o.a.catalina.core.AprLifecycleListener : The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: [D:\jdk1.8.0_161\bin;C:\WINDOWS\Sun\Java\bin;C:\WINDOWS\system32;C:\WINDOWS;D:/jdk1.8.0_161/bin/../jre/bin/server;D:/jdk1.8.0_161/bin/../jre/bin;D:/jdk1.8.0_161/bin/../jre/lib/amd64;D:\app\chenjianfei\product\11.2.0\client_1\bin;C:\Program Files (x86)\Intel\iCLS Client\;C:\Program Files\Intel\iCLS Client\;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files\Intel\Intel(R) Management Engine Components\IPT;D:\jdk1.8.0_161\bin;D:\apache-maven-3.5.2\bin;D:\Git\cmd;D:\gradle-4.5\bin;D:\scala-2.12.6\bin;D:\zookeeper-3.4.12\bin;D:\Program Files\TortoiseSVN\bin;C:\Program Files\Intel\WiFi\bin\;C:\Program Files\Common Files\Intel\WirelessCommon\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\Intel\WiFi\bin\;C:\Program Files\Common Files\Intel\WirelessCommon\;C:\Users\chenjianfei\AppData\Local\Microsoft\WindowsApps;C:\Users\chenjianfei\AppData\Local\GitHubDesktop\bin;D:\STS_4.0;;.]
2018-10-02 09:00:56.173 INFO 12696 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2018-10-02 09:00:56.173 INFO 12696 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 1445 ms
2018-10-02 09:00:56.223 INFO 12696 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean : Servlet dispatcherServlet mapped to [/]
2018-10-02 09:00:56.227 INFO 12696 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/*]
2018-10-02 09:00:56.228 INFO 12696 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2018-10-02 09:00:56.228 INFO 12696 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2018-10-02 09:00:56.228 INFO 12696 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'requestContextFilter' to: [/*]
2018-10-02 09:00:56.355 INFO 12696 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-10-02 09:00:56.571 INFO 12696 --- [ main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.web.ser[email protected]5a955565: startup date [Tue Oct 02 09:00:54 CST 2018]; root of context hierarchy
2018-10-02 09:00:56.629 INFO 12696 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2018-10-02 09:00:56.631 INFO 12696 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2018-10-02 09:00:56.653 INFO 12696 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-10-02 09:00:56.653 INFO 12696 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-10-02 09:00:56.803 INFO 12696 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup
2018-10-02 09:00:56.850 INFO 12696 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8181 (http) with context path ''
2018-10-02 09:00:56.853 INFO 12696 --- [ main] vip.fkandy.Application : Started Application in 2.406 seconds (JVM running for 3.121)
{c[email protected]69adf72c}
再舉個例子：使用Spring Boot提供的@ConditionalOnJava
package vip.fkandy.config;
import org.springframework.boot.SpringBootConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnJava;
import org.springframework.boot.autoconfigure.condition.ConditionalOnJava.Range;
import org.springframework.boot.system.JavaVersion;
import org.springframework.context.annotation.Bean;
@SpringBootConfiguration
public class JDKVersionConfig {
@Bean
@ConditionalOnJava(range = Range.EQUAL_OR_NEWER, value = JavaVersion.EIGHT)
public Runnable createJDKVersion1() {
System.out.println("testJDKVersion1");
return () -> {
};
}
@ConditionalOnJava(range = Range.OLDER_THAN, value = JavaVersion.EIGHT)
public Runnable createJDKVersion2() {
System.out.println("testJDKVersion2");
return () -> {
};
}
}
以上這個例子會輸出testJDKVersion1，因為當前編譯環境的jdk版本為1.8
再舉個例子：
①屬性檔案中server.port=8181的時候載入
②類路徑下包含指定類才載入
③根據容器中是否存在某個Bean才載入
package vip.fkandy.config;
import org.springframework.boot.SpringBootConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.context.annotation.Bean;
/**
* 兩個小例子
*
* @author chenjianfei
*
*/
@SpringBootConfiguration
public class ConfigurationConfig {
/**
* 屬性檔案包含server.port=8181的時候載入bean
*
* @return
*/
@Bean
@ConditionalOnProperty(name = "server.port", havingValue = "8181")
public Runnable createRunnable() {
return () -> {
};
}
/**
* 類路徑下(是否在pom中包含依賴)包含指定的類才載入
*
* @return
*/
@Bean
@ConditionalOnClass(name = "com.google.gson.Gson")
public Runnable createGsonRunnable() {
return () -> {
};
}
/**
* Spring容器中包含指定的Bean才載入(只有建立了User類，並使其加入到容器中)
*
* @return
*/
@Bean
@ConditionalOnBean(name = "user")
public Runnable createBeannRunnable() {
return () -> {
};
}
}
更多資料：