Spring boot day1学习

1. 先安装Idea。。。

2. 配置Maven。。。仓库。:https://blog.csdn.net/github_37759996/article/details/90748461

3. 新建Project，创建HelloWorld。

Spring boot配置：(springboot与maven版本对应:https://www.cnblogs.com/oumi/p/9241424.html)(springboot与jdk版本对应关系：https://www.cnblogs.com/harrychinese/p/jdk_and_springboot_version.html  https://blog.csdn.net/wj197927/article/details/79563081）

    <parent>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-parent</artifactId>
      <version>2.3.1.RELEASE</version>
    </parent>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>

>>写Java接口，返回json格式的数据(REST)

>>发布服务

>>监控服务器运行状态，当前的CPU，和访问人数：java 服务器监控

开发成功了怎么部署呢？

>>SpringBoot2.3.1参考文档：https://docs.spring.io/spring-boot/docs/2.3.1.RELEASE/reference/htmlsingle/

>>Spring Boot Github:https://github.com/spring-projects/spring-boot/

>>官网：https://spring.io/projects/spring-boot/

Spring Boot的优点：

 添加以下配置代码可以将我们的应用打包成一个可独立运行的jar包。

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

然后在jar包所在目录执行

>>类似的服务：NodeJS server.js、Live Server也可以做后端吗？为什么不如Python、Java做后端好

打包之后的应用包含的jar包。。

可以看到里面有嵌入式的tomcat。。为什么没有jetty呢？

SpringBoot的依赖：

SpringBoot启动器Starters

Table 1. Spring Boot application starters

Name	Description
spring-boot-starter	Core starter, including auto-configuration support, logging and YAML
spring-boot-starter-activemq	Starter for JMS messaging using Apache ActiveMQ
spring-boot-starter-amqp	Starter for using Spring AMQP and Rabbit MQ
spring-boot-starter-aop	Starter for aspect-oriented programming with Spring AOP and AspectJ
spring-boot-starter-artemis	Starter for JMS messaging using Apache Artemis
spring-boot-starter-batch	Starter for using Spring Batch
spring-boot-starter-cache	Starter for using Spring Framework’s caching support
spring-boot-starter-data-cassandra	Starter for using Cassandra distributed database and Spring Data Cassandra
spring-boot-starter-data-cassandra-reactive	Starter for using Cassandra distributed database and Spring Data Cassandra Reactive
spring-boot-starter-data-couchbase	Starter for using Couchbase document-oriented database and Spring Data Couchbase
spring-boot-starter-data-couchbase-reactive	Starter for using Couchbase document-oriented database and Spring Data Couchbase Reactive
spring-boot-starter-data-elasticsearch	Starter for using Elasticsearch search and analytics engine and Spring Data Elasticsearch
spring-boot-starter-data-jdbc	Starter for using Spring Data JDBC
spring-boot-starter-data-jpa	Starter for using Spring Data JPA with Hibernate
spring-boot-starter-data-ldap	Starter for using Spring Data LDAP
spring-boot-starter-data-mongodb	Starter for using MongoDB document-oriented database and Spring Data MongoDB
spring-boot-starter-data-mongodb-reactive	Starter for using MongoDB document-oriented database and Spring Data MongoDB Reactive
spring-boot-starter-data-neo4j	Starter for using Neo4j graph database and Spring Data Neo4j
spring-boot-starter-data-r2dbc	Starter for using Spring Data R2DBC
spring-boot-starter-data-redis	Starter for using Redis key-value data store with Spring Data Redis and the Lettuce client
spring-boot-starter-data-redis-reactive	Starter for using Redis key-value data store with Spring Data Redis reactive and the Lettuce client
spring-boot-starter-data-rest	Starter for exposing Spring Data repositories over REST using Spring Data REST
spring-boot-starter-data-solr	Starter for using the Apache Solr search platform with Spring Data Solr
spring-boot-starter-freemarker	Starter for building MVC web applications using FreeMarker views
spring-boot-starter-groovy-templates	Starter for building MVC web applications using Groovy Templates views
spring-boot-starter-hateoas	Starter for building hypermedia-based RESTful web application with Spring MVC and Spring HATEOAS
spring-boot-starter-integration	Starter for using Spring Integration
spring-boot-starter-jdbc	Starter for using JDBC with the HikariCP connection pool
spring-boot-starter-jersey	Starter for building RESTful web applications using JAX-RS and Jersey. An alternative to spring-boot-starter-web
spring-boot-starter-jooq	Starter for using jOOQ to access SQL databases. An alternative to spring-boot-starter-data-jpa or spring-boot-starter-jdbc
spring-boot-starter-json	Starter for reading and writing json
spring-boot-starter-jta-atomikos	Starter for JTA transactions using Atomikos
spring-boot-starter-jta-bitronix	Starter for JTA transactions using Bitronix. Deprecated since 2.3.0
spring-boot-starter-mail	Starter for using Java Mail and Spring Framework’s email sending support
spring-boot-starter-mustache	Starter for building web applications using Mustache views
spring-boot-starter-oauth2-client	Starter for using Spring Security’s OAuth2/OpenID Connect client features
spring-boot-starter-oauth2-resource-server	Starter for using Spring Security’s OAuth2 resource server features
spring-boot-starter-quartz	Starter for using the Quartz scheduler
spring-boot-starter-rsocket	Starter for building RSocket clients and servers
spring-boot-starter-security	Starter for using Spring Security
spring-boot-starter-test	Starter for testing Spring Boot applications with libraries including JUnit, Hamcrest and Mockito
spring-boot-starter-thymeleaf	Starter for building MVC web applications using Thymeleaf views
spring-boot-starter-validation	Starter for using Java Bean Validation with Hibernate Validator
spring-boot-starter-web	Starter for building web, including RESTful, applications using Spring MVC. Uses Tomcat as the default embedded container
spring-boot-starter-web-services	Starter for using Spring Web Services
spring-boot-starter-webflux	Starter for building WebFlux applications using Spring Framework’s Reactive Web support
spring-boot-starter-websocket	Starter for building WebSocket applications using Spring Framework’s WebSocket support

https://docs.spring.io/spring-boot/docs/2.3.1.RELEASE/reference/htmlsingle/#using-boot-starter

In addition to the application starters, the following starters can be used to add production ready features:

Table 2. Spring Boot production starters

Name	Description
spring-boot-starter-actuator	Starter for using Spring Boot’s Actuator which provides production ready features to help you monitor and manage your application

Finally, Spring Boot also includes the following starters that can be used if you want to exclude or swap specific technical facets:

Table 3. Spring Boot technical starters

Name	Description
spring-boot-starter-jetty	Starter for using Jetty as the embedded servlet container. An alternative to spring-boot-starter-tomcat
spring-boot-starter-log4j2	Starter for using Log4j2 for logging. An alternative to spring-boot-starter-logging
spring-boot-starter-logging	Starter for logging using Logback. Default logging starter
spring-boot-starter-reactor-netty	Starter for using Reactor Netty as the embedded reactive HTTP server.
spring-boot-starter-tomcat	Starter for using Tomcat as the embedded servlet container. Default servlet container starter used by spring-boot-starter-web
spring-boot-starter-undertow	Starter for using Undertow as the embedded servlet container. An alternative to spring-boot-starter-tomcat

For a list of additional community contributed starters, see the README file in the spring-boot-starters module on GitHub.

Spring Boot将所有的功能场景都抽取出来，做成一个个的starters（启动器），只需要在项目里面引入这些starters，相关场景的所有依赖都会导入进来。要用什么功能就导入什么场景的启动器

ArcGIS Server REST：

标注SpringBootApplication在某个类之上说明这个类是SpringBoot的主配置类，SpringBoot就应该运行这个类的main方法来启动SpringBoot应用；

HelloWorld细节-自动配置：

以前我们需要配置的东西，Spring Boot帮我们自动配置；@EnableAutoConfiguration告诉SpringBoot开启自动配置功能；这样自动配置才能生效；它将SpringBootApplication类所在包及下面所有子包里面的所有组件扫描到Spring容器；