SpringBoot2.X项目使用微服务V0.0
在学习《史上最简单的Spring Cloud教程》时突发奇想，把原来的项目转为微服务
记录学习历程。
1.首先创建一个Maven主工程，在pom文件中添加模块
本机Eclipse中安装了STS即（Spring Tool Suite），在Eclipse中Help->Eclipse MarketPlace->搜索Spring
可以快速创建SpringBoot应用
先创建一个SpringBoot项目，pom.xml添加SpringCloud版本Finchley,如下
4.0.0
com.damionew
Damionew
0.0.1-SNAPSHOT
pom
Damionew
SpringCloud主Maven项目
org.springframework.boot
spring-boot-starter-parent
2.0.5.RELEASE
damionew-eureka
service-hi
UTF-8
UTF-8
1.8
Finchley.RELEASE
org.springframework.boot
spring-boot-starter
org.springframework.boot
spring-boot-starter-test
test
org.springframework.boot
spring-boot-maven-plugin
2.创建两个模块，Eureka服务注册中心和Eureka客户端进行测试
右键主项目，选择new->other->收入Maven Module搜索添加
如果出现
The parent project must have a packaging type of POM
则是因为在主项目中packing属性不是pom，修改即可
next->next->next
生成pom，整理并添加eureka-server依赖
发现会报'dependencies.dependency.version' is missing for xxx的错误，检查后找到原因是：在主项目的pom.xml中没有添加
org.springframework.cloud
spring-cloud-dependencies
${spring-cloud.version}
pom
import
进行依赖版本控制，添加后解决
在服务注册中心的启动类中添加@EnableEurekaServer以开启SpringCloud Eureka Server
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
@SpringBootApplication
@EnableEurekaServer
public class DamionewEurekaApplication {
public static void main(String[] args) {
SpringApplication.run(DamionewEurekaApplication.class, args);
}
}
包名不能有-，稍作调整，调整为SpringBoot项目结构即可
此时项目结构如图
配置application.properties
# 应用程序名称
#spring.application.name=eureka-server
# 应用端口
server.port=8001
spring.freemarker.prefer-file-system-access=false
# 服务注册中心配置
# 服务注册中心实例的主机名
eureka.instance.hostname=localhost
# 是否向服务注册中心注册自己
eureka.client.register-with-eureka=false
# 是否检索服务
eureka.client.fetch-registry=false
# 服务中心的配置内容，指定服务注册中心的位置
eureka.client.service-url.defaultZone:http://${eureka.instance.hostname}:${server.port}/eureka/
但是当启动项目后，访问localhost:8001时报404
搞了很久不得其解
先试着做了一下Eureka Client，发现可以找到服务注册中心，只是服务注册中心无法进入管理页面
如下
pom.xml，因为加了一个Controller测试所以加了-web的依赖，另外此处引用Eureka的客户端依赖
4.0.0
com.damionew
Damionew-Hi
0.0.1-SNAPSHOT
Damionew-Hi
http://maven.apache.org
com.damionew
Damionew
0.0.1-SNAPSHOT
UTF-8
org.springframework.cloud
spring-cloud-starter-netflix-eureka-client
org.springframework.boot
spring-boot-starter-web
启动类
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@EnableEurekaClient
@SpringBootApplication
@RestController
public class HiApplication {
public static void main(String[] args) {
SpringApplication.run(HiApplication.class, args);
}
@Value("${server.port}")
String port;
@RequestMapping("/hi")
public String hi() {
return "hi";
}
}
配置文件，注意端口要和服务注册中心端口不同，并且eureka.client.service-url.defaultZone使用服务注册中心地址
# 应用程序名称
spring.application.name=eureka-server
# 应用端口
server.port=8002
eureka.client.service-url.defaultZone:http://localhost:8001/eureka/
启动Eureka和Hi项目后可以通过控制台查看
Hi项目打印
2018-09-13 17:18:39.698 INFO 20064 --- [nfoReplicator-0] com.netflix.discovery.DiscoveryClient : DiscoveryClient_EUREKA-SERVER/localhost:eureka-server:8002: registering service...
2018-09-13 17:18:39.835 INFO 20064 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8002 (http) with context path ''
2018-09-13 17:18:39.839 INFO 20064 --- [ main] .s.c.n.e.s.EurekaAutoServiceRegistration : Updating port to 8002
2018-09-13 17:18:39.846 INFO 20064 --- [ main] com.hi.HiApplication : Started HiApplication in 12.78 seconds (JVM running for 14.074)
2018-09-13 17:18:39.924 INFO 20064 --- [nfoReplicator-0] com.netflix.discovery.DiscoveryClient : DiscoveryClient_EUREKA-SERVER/localhost:eureka-server:8002 - registration status: 204如果没有连接到服务注册中心，会连续报错，而服务注册中心有心跳检测功能，每隔几秒就会检测一次
com.netflix.discovery.shared.transport.TransportException: Cannot execute request on any known server
at com.netflix.discovery.shared.transport.decorator.RetryableEurekaHttpClient.execute(RetryableEurekaHttpClient.java:112) ~[eureka-client-1.9.2.jar:1.9.2]
at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator.getDelta(EurekaHttpClientDecorator.java:149) ~[eureka-client-1.9.2.jar:1.9.2]
at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator$7.execute(EurekaHttpClientDecorator.java:152) ~[eureka-client-1.9.2.jar:1.9.2]
at com.netflix.discovery.shared.transport.decorator.SessionedEurekaHttpClient.execute(SessionedEurekaHttpClient.java:77) ~[eureka-client-1.9.2.jar:1.9.2]
at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator.getDelta(EurekaHttpClientDecorator.java:149) ~[eureka-client-1.9.2.jar:1.9.2]
at com.netflix.discovery.DiscoveryClient.getAndUpdateDelta(DiscoveryClient.java:1085) [eureka-client-1.9.2.jar:1.9.2]
at com.netflix.discovery.DiscoveryClient.fetchRegistry(DiscoveryClient.java:967) [eureka-client-1.9.2.jar:1.9.2]
at com.netflix.discovery.DiscoveryClient.refreshRegistry(DiscoveryClient.java:1471) [eureka-client-1.9.2.jar:1.9.2]
at com.netflix.discovery.DiscoveryClient$CacheRefreshThread.run(DiscoveryClient.java:1438) [eureka-client-1.9.2.jar:1.9.2]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [na:1.8.0_144]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) [na:1.8.0_144]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_144]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_144]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_144]但是没有Eureka管理页面真的很难受
修改了一下pom文件，将spring改为1.X且Cloud改为Brixton.SR5后管理页面就出来了。
到家以后换了个电脑发现，用原来的版本就可以显示
猜测是有些jar包还是使用的以前仓库中的，没有更新，导致不匹配