依赖管理 <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.3.4.RELEASE</version> </parent> 他的父项目 <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-dependencies</artifactId> <version>2.3.4.RELEASE</version> </parent> 几乎声明了所有开发中常用的依赖的版本号,自动版本仲裁机制
1、见到很多 spring-boot-starter-* : *就某种场景 2、只要引入starter,这个场景的所有常规需要的依赖我们都自动引入 3、SpringBoot所有支持的场景 https://docs.spring.io/spring-boot/docs/current/reference/html/using-spring-boot.html#using-boot-starter 4、见到的 *-spring-boot-starter: 第三方为我们提供的简化开发的场景启动器。 5、所有场景启动器最底层的依赖 <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> <version>2.3.4.RELEASE</version> <scope>compile</scope> </dependency>
1、引入依赖默认都可以不写版本 2、引入非版本仲裁的jar,要写版本号。
1、查看spring-boot-dependencies里面规定当前依赖的版本 用的 key。 2、在当前项目里面重写配置 <properties> <mysql.version>5.1.43</mysql.version> </properties>
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-tomcat</artifactId> <version>2.3.4.RELEASE</version> <scope>compile</scope> </dependency>
@SpringBootApplication 等同于 @SpringBootConfiguration @EnableAutoConfiguration @ComponentScan("com.atguigu.boot")
#############################Configuration使用示例###################################################### /** * 1、配置类里面使用@Bean标注在方法上给容器注册组件,默认也是单实例的 * 2、配置类本身也是组件 * 3、proxyBeanMethods:代理bean的方法 * Full(proxyBeanMethods = true)、【保证每个@Bean方法被调用多少次返回的组件都是单实例的】 * Lite(proxyBeanMethods = false)【每个@Bean方法被调用多少次返回的组件都是新创建的】 * 组件依赖必须使用Full模式默认。其他默认是否Lite模式 * * * */ @Configuration(proxyBeanMethods = false) //告诉SpringBoot这是一个配置类 == 配置文件 public class MyConfig { /** * Full:外部无论对配置类中的这个组件注册方法调用多少次获取的都是之前注册容器中的单实例对象 * @return */ @Bean //给容器中添加组件。以方法名作为组件的id。返回类型就是组件类型。返回的值,就是组件在容器中的实例 public User user01(){ User zhangsan = new User("zhangsan", 18); //user组件依赖了Pet组件 zhangsan.setPet(tomcatPet()); return zhangsan; } @Bean("tom") public Pet tomcatPet(){ return new Pet("tomcat"); } } ################################@Configuration测试代码如下######################################## @SpringBootConfiguration @EnableAutoConfiguration @ComponentScan("com.atguigu.boot") public class MainApplication { public static void main(String[] args) { //1、返回我们IOC容器 ConfigurableApplicationContext run = SpringApplication.run(MainApplication.class, args); //2、查看容器里面的组件 String[] names = run.getBeanDefinitionNames(); for (String name : names) { System.out.println(name); } //3、从容器中获取组件 Pet tom01 = run.getBean("tom", Pet.class); Pet tom02 = run.getBean("tom", Pet.class); System.out.println("组件:"+(tom01 == tom02)); //4、com.atguigu.boot.config.MyConfig$$EnhancerBySpringCGLIB$$51f1e1ca@1654a892 MyConfig bean = run.getBean(MyConfig.class); System.out.println(bean); //如果@Configuration(proxyBeanMethods = true)代理对象调用方法。SpringBoot总会检查这个组件是否在容器中有。 //保持组件单实例 User user = bean.user01(); User user1 = bean.user01(); System.out.println(user == user1); User user01 = run.getBean("user01", User.class); Pet tom = run.getBean("tom", Pet.class); System.out.println("用户的宠物:"+(user01.getPet() == tom)); } }
* 4、@Import({User.class, DBHelper.class}) * 给容器中自动创建出这两个类型的组件、默认组件的名字就是全类名 * * * */ @Import({User.class, DBHelper.class}) @Configuration(proxyBeanMethods = false) //告诉SpringBoot这是一个配置类 == 配置文件 public class MyConfig { }
@Import 高级用法: https://www.bilibili.com/video/BV1gW411W7wy?p=8
条件装配:满足Conditional指定的条件,则进行组件注入
=====================测试条件装配========================== @Configuration(proxyBeanMethods = false) //告诉SpringBoot这是一个配置类 == 配置文件 //@ConditionalOnBean(name = "tom") @ConditionalOnMissingBean(name = "tom") public class MyConfig { /** * Full:外部无论对配置类中的这个组件注册方法调用多少次获取的都是之前注册容器中的单实例对象 * @return */ @Bean //给容器中添加组件。以方法名作为组件的id。返回类型就是组件类型。返回的值,就是组件在容器中的实例 public User user01(){ User zhangsan = new User("zhangsan", 18); //user组件依赖了Pet组件 zhangsan.setPet(tomcatPet()); return zhangsan; } @Bean("tom22") public Pet tomcatPet(){ return new Pet("tomcat"); } } public static void main(String[] args) { //1、返回我们IOC容器 ConfigurableApplicationContext run = SpringApplication.run(MainApplication.class, args); //2、查看容器里面的组件 String[] names = run.getBeanDefinitionNames(); for (String name : names) { System.out.println(name); } boolean tom = run.containsBean("tom"); System.out.println("容器中Tom组件:"+tom); boolean user01 = run.containsBean("user01"); System.out.println("容器中user01组件:"+user01); boolean tom22 = run.containsBean("tom22"); System.out.println("容器中tom22组件:"+tom22); }
======================beans.xml========================= <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd"> <bean id="haha" class="com.atguigu.boot.bean.User"> <property name="name" value="zhangsan"></property> <property name="age" value="18"></property> </bean> <bean id="hehe" class="com.atguigu.boot.bean.Pet"> <property name="name" value="tomcat"></property> </bean> </beans>
@ImportResource("classpath:beans.xml") public class MyConfig {} ======================测试================= boolean haha = run.containsBean("haha"); boolean hehe = run.containsBean("hehe"); System.out.println("haha:"+haha);//true System.out.println("hehe:"+hehe);//true
如何使用Java读取到properties文件中的内容,并且把它封装到JavaBean中,以供随时使用;
public class getProperties { public static void main(String[] args) throws FileNotFoundException, IOException { Properties pps = new Properties(); pps.load(new FileInputStream("a.properties")); Enumeration enum1 = pps.propertyNames();//得到配置文件的名字 while(enum1.hasMoreElements()) { String strKey = (String) enum1.nextElement(); String strValue = pps.getProperty(strKey); System.out.println(strKey + "=" + strValue); //封装到JavaBean。 } } }
/** * 只有在容器中的组件,才会拥有SpringBoot提供的强大功能 */ @Component @ConfigurationProperties(prefix = "mycar") public class Car { private String brand; private Integer price; public String getBrand() { return brand; } public void setBrand(String brand) { this.brand = brand; } public Integer getPrice() { return price; } public void setPrice(Integer price) { this.price = price; } @Override public String toString() { return "Car{" + "brand=‘" + brand + ‘\‘‘ + ", price=" + price + ‘}‘; } }
@EnableConfigurationProperties(Car.class) //1、开启Car配置绑定功能 //2、把这个Car这个组件自动注册到容器中 public class MyConfig { }
@SpringBootConfiguration @EnableAutoConfiguration @ComponentScan(excludeFilters = { @Filter(type = FilterType.CUSTOM, classes = TypeExcludeFilter.class), @Filter(type = FilterType.CUSTOM, classes = AutoConfigurationExcludeFilter.class) }) public @interface SpringBootApplication{} ======================
@Configuration。代表当前是一个配置类
指定扫描哪些,Spring注解;
@AutoConfigurationPackage @Import(AutoConfigurationImportSelector.class) public @interface EnableAutoConfiguration {}
自动配置包?指定了默认的包规则
@Import(AutoConfigurationPackages.Registrar.class) //给容器中导入一个组件 public @interface AutoConfigurationPackage {} //利用Registrar给容器中导入一系列组件 //将指定的一个包下的所有组件导入进来?MainApplication 所在包下。
1、利用getAutoConfigurationEntry(annotationMetadata);给容器中批量导入一些组件 2、调用List<String> configurations = getCandidateConfigurations(annotationMetadata, attributes)获取到所有需要导入到容器中的配置类 3、利用工厂加载 Map<String, List<String>> loadSpringFactories(@Nullable ClassLoader classLoader);得到所有的组件 4、从META-INF/spring.factories位置来加载一个文件。 默认扫描我们当前系统里面所有META-INF/spring.factories位置的文件 spring-boot-autoconfigure-2.3.4.RELEASE.jar包里面也有META-INF/spring.factories
文件里面写死了spring-boot一启动就要给容器中加载的所有配置类 spring-boot-autoconfigure-2.3.4.RELEASE.jar/META-INF/spring.factories # 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.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.r2dbc.R2dbcTransactionManagerAutoConfiguration,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.orm.jpa.HibernateJpaAutoConfiguration,org.springframework.boot.autoconfigure.quartz.QuartzAutoConfiguration,org.springframework.boot.autoconfigure.r2dbc.R2dbcAutoConfiguration,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
虽然我们127个场景的所有自动配置启动的时候默认全部加载。xxxxAutoConfiguration 按照条件装配规则(@Conditional),最终会按需配置。
@Bean @ConditionalOnBean(MultipartResolver.class) //容器中有这个类型组件 @ConditionalOnMissingBean(name = DispatcherServlet.MULTIPART_RESOLVER_BEAN_NAME) //容器中没有这个名字 multipartResolver 的组件 public MultipartResolver multipartResolver(MultipartResolver resolver) { //给@Bean标注的方法传入了对象参数,这个参数的值就会从容器中找。 //SpringMVC multipartResolver。防止有些用户配置的文件上传解析器不符合规范 // Detect if the user has created a MultipartResolver but named it incorrectly return resolver; } 给容器中加入了文件上传解析器;
SpringBoot默认会在底层配好所有的组件。但是如果用户自己配置了以用户的优先
@Bean @ConditionalOnMissingBean public CharacterEncodingFilter characterEncodingFilter() { }
xxxxxAutoConfiguration ---> 组件 ---> xxxxProperties里面拿值 ----> application.properties
简化JavaBean开发
<dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> </dependency> idea中搜索安装lombok插件
===============================简化JavaBean开发=================================== @NoArgsConstructor //@AllArgsConstructor @Data @ToString @EqualsAndHashCode public class User { private String name; private Integer age; private Pet pet; public User(String name,Integer age){ this.name = name; this.age = age; } } ================================简化日志开发=================================== @Slf4j @RestController public class HelloController { @RequestMapping("/hello") public String handle01(@RequestParam("name") String name){ log.info("请求进来了...."); return "Hello, Spring Boot 2!"+"你好:"+name; } }
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> <optional>true</optional> </dependency>
项目或者页面修改以后:Ctrl+F9;
原文:https://www.cnblogs.com/taozhiyaoyao99/p/15247103.html