SpringBoot监听机制-以及使用

11-SpringBoot事件监听

Java中的事件监听机制定义了以下几个角色：

①事件：Event，继承 java.util.EventObject 类的对象

②事件源：Source ，任意对象Object

③监听器：Listener，实现 java.util.EventListener 接口 的对象

SpringBoot 在项目启动时，会对几个监听器进行回调，我们可以实现这些监听器接口，在项目启动时完成一些操作。

• ApplicationContextInitializer、

• SpringApplicationRunListener、

• CommandLineRunner、

• ApplicationRunner

  自定义监听器的启动时机：MyApplicationRunner和MyCommandLineRunner都是当项目启动后执行，使用@Component放入容器即可使用
  yApplicationRunner

/*** 当项目启动后执行run方法。* 缓存数据*/
@Component
public class MyApplicationRunner implements ApplicationRunner {@Overridepublic void run(ApplicationArguments args) throws Exception {System.out.println("ApplicationRunner...run");System.out.println(Arrays.asList(args.getSourceArgs()));}
} 

MyCommandLineRunner

@Component
public class MyCommandLineRunner implements CommandLineRunner {@Overridepublic void run(String... args) throws Exception {System.out.println("CommandLineRunner...run");System.out.println(Arrays.asList(args));}
}

MyApplicationContextInitializer的使用要在resource文件夹下添加META-INF/spring.factories

org.springframework.context.ApplicationContextInitializer=com.itheima.springbootlistener.listener.MyApplicationContextInitializer

@Component
public class MyApplicationContextInitializer implements ApplicationContextInitializer {@Overridepublic void initialize(ConfigurableApplicationContext applicationContext) {System.out.println("ApplicationContextInitializer....initialize");}
}

MySpringApplicationRunListener的使用要添加构造器

public class MySpringApplicationRunListener implements SpringApplicationRunListener {public MySpringApplicationRunListener(SpringApplication application, String[] args) {}@Overridepublic void starting() {System.out.println("starting...项目启动中");}@Overridepublic void environmentPrepared(ConfigurableEnvironment environment) {System.out.println("environmentPrepared...环境对象开始准备");}@Overridepublic void contextPrepared(ConfigurableApplicationContext context) {System.out.println("contextPrepared...上下文对象开始准备");}@Overridepublic void contextLoaded(ConfigurableApplicationContext context) {System.out.println("contextLoaded...上下文对象开始加载");}@Overridepublic void started(ConfigurableApplicationContext context) {System.out.println("started...上下文对象加载完成");}@Overridepublic void running(ConfigurableApplicationContext context) {System.out.println("running...项目启动完成，开始运行");}@Overridepublic void failed(ConfigurableApplicationContext context, Throwable exception) {System.out.println("failed...项目启动失败");}
}

12-SpringBoot流程分析-初始化

1. 配置启动引导类（判断是否有启动主类）

2. 判断是否是Web环境

3. 获取初始化类、监听器类

13-SpringBoot流程分析-run

1. 启动计时器

2. 执行监听器

3. 准备环境

4. 打印banner：可以resource下粘贴自定义的banner

5. 创建context

   refreshContext(context);
   

   执行refreshContext方法后才真正创建Bean

   

14-SpringBoot监控-actuator基本使用

①导入依赖坐标

<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-actuator</artifactId></dependency>

②访问http://localhost:8080/acruator

{"_links":{"self":{"href":"http://localhost:8080/actuator","templated":false},"health":{"href":"http://localhost:8080/actuator/health","templated":false},"health-component-instance":{"href":"http://localhost:8080/actuator/health/{component}/{instance}","templated":true},"health-component":{"href":"http://localhost:8080/actuator/health/{component}","templated":true},"info":{"href":"http://localhost:8080/actuator/info","templated":false}}
}

http://localhost:8080/actuator/info

在application.properties中配置

info.name=lucy
info.age=99

http://localhost:8080/actuator/health

开启健康检查详细信息

management.endpoint.health.show-details=always

{"status":"UP","details":{"diskSpace":{"status":"UP","details":{"total":159579508736,"free":13558104064,"threshold":10485760}},"redis":{"status":"UP","details":{"version":"2.4.5"}}}
}

15-SpringBoot监控-actuator开启所有endpoint

开启所有endpoint

在application.properties中配置：

management.endpoints.web.exposure.include=*

开启所有endpoint的返回结果：

{"_links":{"self":{"href":"http://localhost:8080/actuator","templated":false},"auditevents":{"href":"http://localhost:8080/actuator/auditevents","templated":false},"beans":{"href":"http://localhost:8080/actuator/beans","templated":false},"caches-cache":{"href":"http://localhost:8080/actuator/caches/{cache}","templated":true},"caches":{"href":"http://localhost:8080/actuator/caches","templated":false},"health-component-instance":{"href":"http://localhost:8080/actuator/health/{component}/{instance}","templated":true},"health":{"href":"http://localhost:8080/actuator/health","templated":false},"health-component":{"href":"http://localhost:8080/actuator/health/{component}","templated":true},"conditions":{"href":"http://localhost:8080/actuator/conditions","templated":false},"configprops":{"href":"http://localhost:8080/actuator/configprops","templated":false},"env":{"href":"http://localhost:8080/actuator/env","templated":false},"env-toMatch":{"href":"http://localhost:8080/actuator/env/{toMatch}","templated":true},"info":{"href":"http://localhost:8080/actuator/info","templated":false},"loggers":{"href":"http://localhost:8080/actuator/loggers","templated":false},"loggers-name":{"href":"http://localhost:8080/actuator/loggers/{name}","templated":true},"heapdump":{"href":"http://localhost:8080/actuator/heapdump","templated":false},"threaddump":{"href":"http://localhost:8080/actuator/threaddump","templated":false},"metrics-requiredMetricName":{"href":"http://localhost:8080/actuator/metrics/{requiredMetricName}","templated":true},"metrics":{"href":"http://localhost:8080/actuator/metrics","templated":false},"scheduledtasks":{"href":"http://localhost:8080/actuator/scheduledtasks","templated":false},"httptrace":{"href":"http://localhost:8080/actuator/httptrace","templated":false},"mappings":{"href":"http://localhost:8080/actuator/mappings","templated":false}}
}

16-SpringBoot监控-springboot admin图形化界面使用

SpringBoot Admin 有两个角色，客户端(Client)和服务端(Server)。

以下为创建服务端和客户端工程步骤：

admin-server：

①创建 admin-server 模块

②导入依赖坐标 admin-starter-server

      <dependency><groupId>de.codecentric</groupId><artifactId>spring-boot-admin-starter-server</artifactId></dependency>

③在引导类上启用监控功能@EnableAdminServer

@EnableAdminServer
@SpringBootApplication
public class SpringbootAdminServerApplication {public static void main(String[] args) {SpringApplication.run(SpringbootAdminServerApplication.class, args);}}

admin-client：

①创建 admin-client 模块

②导入依赖坐标 admin-starter-client

  		<dependency><groupId>de.codecentric</groupId><artifactId>spring-boot-admin-starter-client</artifactId></dependency>

③配置相关信息：server地址等

# 执行admin.server地址
spring.boot.admin.client.url=http://localhost:9000management.endpoint.health.show-details=always
management.endpoints.web.exposure.include=*

④启动server和client服务，访问server

17-SpringBoot部署

SpringBoot 项目开发完毕后，支持两种方式部署到服务器：

①jar包(官方推荐)

②war包

更改pom文件中的打包方式为war

修改启动类

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;@SpringBootApplication
public class SpringbootDeployApplication extends SpringBootServletInitializer {public static void main(String[] args) {SpringApplication.run(SpringbootDeployApplication.class, args);}@Overrideprotected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {return builder.sources(SpringbootDeployApplication.class);}
}

指定打包的名称

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