@EnableAutoConfiguration和@SpringbootApplication注解

一、@EnableAutoConfiguration

The second class-level annotation is @EnableAutoConfiguration. This annotation tells Spring Boot to “guess” how you 
will want to configure Spring, based on the jar dependencies that you have added. Since spring-boot-starter-web added Tomcat and Spring MVC,
the auto-configuration will assume that you are developing a web application and setup Spring accordingly.

Starters and Auto-Configuration Auto-configuration is designed to work well with “Starters”, but the two concepts are not directly tied.
You are free to pick-and-choose jar dependencies outside of the starters and Spring Boot will still do
its best to auto-configure your application.

  这个注释告诉SpringBoot“猜”你将如何想配置Spring,基于你已经添加jar依赖项。如果spring-boot-starter-web已经添加Tomcat和Spring MVC,这个注释自动将假设您正在开发一个web应用程序并添加相应的spring设置。

  自动配置被设计用来和“Starters”一起更好的工作,但这两个概念并不直接相关。您可以自由挑选starter依赖项以外的jar包,springboot仍将尽力自动配置您的应用程序。

  spring通常建议我们将main方法所在的类放到一个root包下,@EnableAutoConfiguration(开启自动配置)注解通常都放到main所在类的上面,下面是一个典型的结构布局:

com
 +- example
     +- myproject
         +- Application.java
         |
         +- domain
         |   +- Customer.java
         |   +- CustomerRepository.java
         |
         +- service
         |   +- CustomerService.java
         |
         +- web
             +- CustomerController.java

  这样@EnableAutoConfiguration可以从逐层的往下搜索各个加注解的类,例如,你正在编写一个JPA程序(如果你的pom里进行了配置的话),spring会自动去搜索加了@Entity注解的类,并进行调用

二、@SpringbootApplication

   使用@SpringbootApplication注解  可以解决根类或者配置类(我自己的说法,就是main所在类)头上注解过多的问题,一个@SpringbootApplication相当于@Configuration,@EnableAutoConfiguration和 @ComponentScan 并具有他们的默认属性值

package com.example.myproject;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication //等同于 @Configuration @EnableAutoConfiguration @ComponentScanpublic
class Application {    
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

}

  

posted @ 2017-06-19 14:31 飞龙在天001 阅读(...) 评论(...) 编辑 收藏