Eureka源码分析

Eureka源码分析

Eureka server

入口:

Spring.factories

PS:

意味着如果加载EurekaServerAutoConfiguration成功,需要

@ConditionalOnBean(EurekaServerMarkerConfiguration.Marker.class)需加载成功.

通过@Bean注入了很多类

本质上, eureka-server包含很多事件:

EurekaInstanceCanceledEvent	服务下线事件
EurekaInstanceRegisteredEvent	服务注册事件
EurekaInstanceRenewedEvent	服务续约事件
EurekaRegistryAvailableEvent	Eureka注册中心启动事件
EurekaServerStartedEvent	Eureka server启动事件

Java扩展: EventObject->EventListener

包含注册\下线\续约等

事件注册之前, 需要有监听器, eureka所用的监听器是EurekaEventListener

针对上面五个事件, 我们可以自定义监听器

package com.macro.cloud;

import com.netflix.appinfo.InstanceInfo;
import org.springframework.cloud.netflix.eureka.server.event.*;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;

@Component
public class EurekaStateChangeListener {
    @EventListener
    public void listen(EurekaInstanceCanceledEvent eurekaInstanceCanceledEvent) {
        //服务断线事件
        String appName = eurekaInstanceCanceledEvent.getAppName();
        String serverId = eurekaInstanceCanceledEvent.getServerId();
        System.out.println(appName);
        System.out.println(serverId);
        System.out.println("EurekaInstanceCanceledEvent");
    }
    @EventListener
    public void listen(EurekaInstanceRegisteredEvent event) {
        InstanceInfo instanceInfo = event.getInstanceInfo();
        System.out.println(instanceInfo);
        System.out.println("EurekaInstanceRegisteredEvent");
    }
    @EventListener
    public void listen(EurekaInstanceRenewedEvent event) {
        event.getAppName();
        event.getServerId();
        System.out.println("EurekaInstanceRenewedEvent");
    }
    @EventListener
    public void listen(EurekaRegistryAvailableEvent event) {
        System.out.println("EurekaRegistryAvailableEvent");
    }
    @EventListener
    public void listen(EurekaServerStartedEvent event) {
        System.out.println("EurekaServerStartedEvent");
        //Server启动
    }
}

其中eureka-server启动时候, 会出发最后两个事件, 即:

EurekaRegistryAvailableEvent 和 EurekaServerStartedEvent.

当eureka-client启动后, 会出发EurekaInstanceRegisteredEvent事件.

Eurekaserver总结如下:

Eureka client

ApplicationListenerMethodAdapter.java

Eureka-client 底层是要了jerseyClient

Builder resourceBuilder = jerseyClient.resource(serviceUrl).path(urlPath).getRequestBuilder();
addExtraHeaders(resourceBuilder);
response = resourceBuilder
        .header("Accept-Encoding", "gzip")
        .type(MediaType.APPLICATION_JSON_TYPE)
        .accept(MediaType.APPLICATION_JSON)
        .post(ClientResponse.class, info);