遗留非springboot传统项目接入eureka注册与服务发现

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最近规划自动化运维以及统一监控需求，鉴于目前公司内部大部分项目采用spring cloud体系架构、另外还有一些老的传统spring web的项目，于是就考虑把老的项目通过低成本改造的方式接入spring cloud体系，也就是可以通过eureka注册和服务发现、通过zuul服务路由。

说干就干，通过eureka官方实例和研究spring boot注册eureka源码发现这个也很容易实现，所以废话不多说，直接贴代码了 。

首先加入项目依赖（maven为例）

<dependency>
    <groupId>com.netflix.eurekagroupId>
    <artifactId>eureka-clientartifactId>
    <version>1.4.12version>
    <exclusions>
        <exclusion>
          <groupId>javax.servletgroupId>
          <artifactId>servlet-apiartifactId>
        exclusion>
        <exclusion>
          <groupId>com.google.guavagroupId>
          <artifactId>guavaartifactId>
        exclusion>
        <exclusion>
          <groupId>com.fasterxml.jackson.coregroupId>
          <artifactId>jackson-annotationsartifactId>
        exclusion>
        <exclusion>
          <groupId>javax.ws.rsgroupId>
          <artifactId>jsr311-apiartifactId>
        exclusion>
    exclusions>
dependency>

    <dependency>
      <groupId>com.netflix.archaiusgroupId>
      <artifactId>archaius-coreartifactId>
      <version>0.7.4version>
      <exclusions>
        <exclusion>
          <groupId>com.fasterxml.jackson.coregroupId>
          <artifactId>jackson-annotationsartifactId>
        exclusion>
      exclusions>
    dependency>

    <dependency>
      <groupId>org.springframework.cloudgroupId>
      <artifactId>spring-cloud-netflix-coreartifactId>
      <version>1.2.6.RELEASEversion>
      <exclusions>
        <exclusion>
          <groupId>org.springframework.bootgroupId>
          <artifactId>spring-boot-autoconfigureartifactId>
        exclusion>
      exclusions>
    dependency>

加入配置文件

eureka.region=default
eureka.registration.enabled=true
eureka.preferSameZone=true
eureka.shouldUseDns=false
eureka.serviceUrl.default=http://192.168.1.100:7861/eureka
eureka.decoderName=JacksonJson

eureka.name=demo
eureka.vipAddress=${eureka.name}-service
eureka.port=8081
eureka.homePageUrl=http://192.168.1.101:${eureka.port}
eureka.healthCheckUrl=http://192.168.1.101:${eureka.port}/service/health
eureka.statusPageUrl=http://192.168.1.101:${eureka.port}/service/info

• spring.cloud.client.ipAddress :为自定义变量
• healthCheckUrl，statusPageUrl接口可以不要，但是为了监控可以自己实现一个简单的接口即可

初始化eureka客户端

private void initEurekaClient() throws Exception{

        Properties properties = new Properties();

        InputStream inputStream = Thread.currentThread().getContextClassLoader().getResourceAsStream("eureka.properties");
        properties.load(inputStream);

        //
        properties.setProperty("eureka.ipAddr", IpUtils.getLocalIpAddr());
        instanceId = properties.getProperty("eureka.ipAddr") + ":" + properties.getProperty("eureka.ipAddr") + "/" + properties.getProperty("eureka.name");
        properties.setProperty("eureka.instanceId", instanceId);

        ConfigurationManager.loadProperties(properties);

        MyDataCenterInstanceConfig instanceConfig = new MyDataCenterInstanceConfig();
        InstanceInfo instanceInfo = new EurekaConfigBasedInstanceInfoProvider(instanceConfig).get();
        applicationInfoManager = new ApplicationInfoManager(instanceConfig, instanceInfo);

        DefaultEurekaClientConfig clientConfig = new DefaultEurekaClientConfig();

        eurekaClient = new DiscoveryClient(applicationInfoManager, clientConfig);

}

注册服务

private void waitForRegistrationWithEureka() {

        applicationInfoManager.setInstanceStatus(InstanceInfo.InstanceStatus.STARTING);
        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {
        }
        applicationInfoManager.setInstanceStatus(InstanceInfo.InstanceStatus.UP);

        long startTime = System.currentTimeMillis();
        //开启一个线程验证注册结果
        new Thread(new Runnable() {
            @Override
            public void run() {
                while (true) {
                    if (System.currentTimeMillis() - startTime > VERIFY_WAIT_MILLIS) {
                        log.warn(" >>>> service registration status not verify,please check it!!!!");
                        return;
                    }
                    try {
                        List serverInfos = eurekaClient.getInstancesByVipAddress(vipAddress, false);
                        for (InstanceInfo nextServerInfo : serverInfos) {
                            if (nextServerInfo.getIPAddr().equals(IpUtils.LOCAL_BACK_IP)
                                    || nextServerInfo.getIPAddr().equals(IpUtils.getLocalIpAddr())) {
                                String instanceInfoJson = JsonUtils.getMapper().writerWithDefaultPrettyPrinter()
                                        .writeValueAsString(nextServerInfo);
                                log.info("verifying service registration with eureka finished,instance:\n{}",
                                        instanceInfoJson);
                                return;
                            }
                        }
                    } catch (Throwable e) {
                    }
                    try {
                        Thread.sleep(5000);
                    } catch (Exception e1) {
                    }
                    log.info("Waiting 5s... verifying service registration with eureka ...");
                }
            }
        }).start();
    }

通过这几步就完成了eureka的注册，登录eureka控制台你将能看到对应注册信息。但是在zuul转发调用过程发现一个问题：无法识别hostname，如果你们的服务器之间没有做hostname同步就需要继续改造，于是就看了下springboot注册eureka有一个配置项eureka.instance.preferIpAddress，所以我们也可以模仿他的实现。于是在初始化客户端的时候我们需要这样改造：

MyDataCenterInstanceConfig instanceConfig = new MyDataCenterInstanceConfig(){
            @Override
            public String getHostName(boolean refresh) {
                String hostName = super.getHostName(refresh);
                if(ResourceUtils.getBoolean("eureka.preferIpAddress")){
                    hostName = IpUtils.getLocalIpAddr();
                }
                return hostName;
            }

            @Override
            public String getIpAddress() {
                return IpUtils.getLocalIpAddr();
            }

};

这样，注册的真实服务地址就是ip了。服务注册就搞定收工了。

接下来就是服务发现，及与其他springboot项目一样通过注册中心vipAddress互相调用。实际过程就是调用前去eureka拿一个真实地址替换vipAddress变量。

获取真实服务地址

public String getRealServerHost(String serviceId){
    InstanceInfo serverInfo = eurekaClient.getNextServerFromEureka(serviceId, false);
    String realServerName = serverInfo.getIPAddr() + ":" + serverInfo.getPort();
    return realServerName;
}

下面是我实现的几个resttemplate

public class EurekaRestTemplateBuilder {

    private static Map restTemplates = new HashMap<>();

    public static synchronized RestTemplate build(ClientHttpRequestInterceptor ...interceptors ){
        return build("default", interceptors);
    }

    public static synchronized RestTemplate build(String name,ClientHttpRequestInterceptor ...interceptors ){

        if(restTemplates.containsKey(name))return restTemplates.get(name);

        SimpleClientHttpRequestFactory factory = new EurekaClientHttpRequestFactory();  
        factory.setReadTimeout(15000);//ms  
        factory.setConnectTimeout(5000);//ms 

        RestTemplate restTemplate = new RestTemplate(factory);
        List interceptorList = new ArrayList<>();
        interceptorList.add(new RestTemplateAutoHeaderInterceptor());
        if(interceptors != null && interceptors.length > 0){
            for (ClientHttpRequestInterceptor interceptor : interceptors) {
                interceptorList.add(interceptor);
            }
        }
        restTemplate.setInterceptors(interceptorList);
        //
        restTemplate.setErrorHandler(new CustomResponseErrorHandler());
        //
        restTemplates.put(name, restTemplate);

        return restTemplate;
    }

    private static class EurekaClientHttpRequestFactory extends SimpleClientHttpRequestFactory{

        @Override
        public ClientHttpRequest createRequest(URI uri, HttpMethod httpMethod) throws IOException {
            uri = convertToRealUri(uri);
            return super.createRequest(uri, httpMethod);
        }

        @Override
        public AsyncClientHttpRequest createAsyncRequest(URI uri, HttpMethod httpMethod) throws IOException {
            uri = convertToRealUri(uri);
            return super.createAsyncRequest(uri, httpMethod);
        }

        private URI convertToRealUri(URI uri){
            String serviceId = uri.getHost();
            try {               
                String realHost = EurekaRegistry.getInstance().getRealServerHost(serviceId);
                uri = new URI(uri.toString().replace(serviceId, realHost));
                return uri;
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }

    }
}

接下来就可以调用其他eureka注册服务了。

private RestTemplate restTemplate = EurekaRestTemplateBuilder.build();

  public List getProvinces() {
    ParameterizedTypeReference<List> arearesponseType = new ParameterizedTypeReference<List>() {
    };
    List lists = restTemplate
        .exchange("http://DEMO-SERVICE/region/provinces", HttpMethod.GET, null, arearesponseType)
        .getBody();
    return lists;
  }

ZUUL转发配置

zuul.routes.demo.path=/demo/**
zuul.routes.demo.serviceId=demo-service

到此，服务注册和服务发现都完成了。
这里是一个demo

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