Spring Boot详解

Spring Boot

启动类注解

@SpringBootApplication

放在某个类上 说明该类是spring boot的主配置类 点开后

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@SpringBootConfiguration
@EnableAutoConfiguration
@ComponentScan(excludeFilters = { @Filter(type = FilterType.CUSTOM, classes = TypeExcludeFilter.class),
      @Filter(type = FilterType.CUSTOM, classes = AutoConfigurationExcludeFilter.class) })
public @interface SpringBootApplication {}

@SpringBootConfiguration( ->spring boot)：

标注在某一个类上表示 spring boot配置类

点开 其实是一个配置类注解

@Configuration  --->spring

@EnableAutoConfiguration:开启自动配置

​ 以前需要配置的 spring boot 自动配置 点进来

@AutoConfigurationPackage
@Import(AutoConfigurationImportSelector.class)
public @interface EnableAutoConfiguration {}

@AutoConfigurationPackage：自动配置包

@Import(AutoConfigurationImportSelector.class)

将主配置类所在包及下面所有子包下所有组件扫描到spring容器

spring底层注解@Import 给容器中导入一个组件

---

@Import(EnableAutoConfigurationSelector.class)

此注解可以配合@Configuration完成配置 示例代码

package com.coding.config;

import com.corundumstudio.socketio.SocketConfig;
import com.corundumstudio.socketio.SocketIOServer;
import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;

@Slf4j
@Configuration
@EnableConfigurationProperties({
        AppProperties.class,
})
public class AppConfiguration {

    @Scope("prototype")
    @Bean
    public SocketIOServer socketIoServer(AppProperties appProperties) {
        SocketConfig socketConfig = new SocketConfig();
        socketConfig.setTcpNoDelay(true);
        socketConfig.setSoLinger(0);
        com.corundumstudio.socketio.Configuration config = new com.corundumstudio.socketio.Configuration();
        config.setSocketConfig(socketConfig);
        config.setHostname(appProperties.getHost());
        config.setPort(appProperties.getPort());
        config.setBossThreads(appProperties.getBossCount());
        config.setWorkerThreads(appProperties.getWorkCount());
        config.setAllowCustomRequests(appProperties.isAllowCustomRequests());
        config.setUpgradeTimeout(appProperties.getUpgradeTimeout());
        config.setPingTimeout(appProperties.getPingTimeout());
        config.setPingInterval(appProperties.getPingInterval());
        return new SocketIOServer(config);
    }

}

//AppProperties.class
package com.coding.config;

import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;

@Data
@Component
@ConfigurationProperties(prefix = "ws")
/*
* @ConfigurationProperties告诉spring boot 将本类中所有属性和配置文件性格配置进行绑定 需要在
* prefix = "??" (可以省略)
*需导入配置文件处理器
* <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
           
        </dependency>
*/
public class AppProperties {
    /**
     * title
     */
    private String title;

    /**
     * host
     */
    private String host;

    /**
     * port
     */
    private Integer port;

    /**
     * bossCount
     */
    private int bossCount;

    /**
     * workCount
     */
    private int workCount;

    /**
     * allowCustomRequests
     */
    private boolean allowCustomRequests;

    /**
     * upgradeTimeout
     */
    private int upgradeTimeout;

    /**
     * pingTimeout
     */
    private int pingTimeout;

    /**
     * pingInterval
     */
    private int pingInterval;
}
//yml
ws:
  port: 8888
  title: arduino服务器
  host: 0.0.0.0
  boss-count: 1
  work-count: 100
  allow-custom-requests: true
  upgrade-timeout: 10000
  ping-timeout: 60000
  ping-interval: 25000

二、配置文件

Spring boot 使用一个全局配置文件

1、application.yml

2、application.properties

(配置文件的作用是对spring boot默认配置进行修改)

yam - properties - xml 示例

#yaml
server:
	port:8081

#properties
server.port=8081

<!--xml-->
<server>
    <port>8081</port>
</server>

yml 缩进控制 大小写敏感

支持字面量，数组、map

Profile切换环境

多配置文件 application-{name}.properties/yml

properties切换环境

spring.profiles.active=?? 

yml切换

server:
  port: 8080
spring:
  profiles:
    active: dev/prod
---
server:
  port: 8081
spring:
  profiles:prod
---
server:
  port: 8081
spring:
  profiles:dev
---

有加载优先级顺序（可做互补配置）也可以把配置文件写在外部

Spring boot 自动装配原理

1、启动时加载主配置类 开启自动配置@EnableConfiguration

2、@EnableConfiguration作用：

​ 利用EnableConfigurationImportSelector 给容器中导入组件

​ 从properties中获取EnableConfiguration.class(类名对应的值)

类路径下 META-INF/spring.factories里面所有EnableConfiguration的值加入到容器中

重点

• spring boot 启动会加载大量自动配置类
• 自动配置类配置了哪些组件，组件有 无需配置
• 给容器自动装配组件时候 会从properties类中获取某些属性 就可以制定这些属性值

xxxAutoConfigurartion:自动配置类

给容器中添加组件

xxxProperties：封装配置文件中相关的属性

嵌入式Servlet容器

后续...