eureka客户端强制刷新可用服务列表-样例

服务端下线接口

@GetMapping(path = "/shutdown")
public String shutdown() {
    //主动将自身从eureka服务器注销
    DiscoveryManager.getInstance().shutdownComponent();
    return "ok";
}

客户端

获取可用服务信息

@Resource
private CachingSpringLoadBalancerFactory lbClientFactory;
@Value("${spring.application.name}")
private String applicationName;

@GetMapping(path = "/serverList")
public Map<String, List<MachineDTO>> getServerList() {
    DiscoveryClient discoveryClient = DiscoveryManager.getInstance().getDiscoveryClient();
    List<Application> applications = discoveryClient.getApplications().getRegisteredApplications();
    if (CollectionUtils.isEmpty(applications)) {
        return Collections.emptyMap();
    }

    List<MachineDTO> machineList;
    Map<String, List<MachineDTO>> result = Maps.newHashMap();
    for (Application application : applications) {
        // 过滤掉自身服务信息
        if (application.getName().equalsIgnoreCase(applicationName)) {
            continue;
        }

        machineList = application.getInstances().stream()
                .map(item -> new MachineDTO(item.getIPAddr(), String.valueOf(item.getPort())))
                .collect(Collectors.toList());
        result.put(application.getName(), machineList);
    }
    return result;
}

/**
 * 机器信息
 * @author liuyong
 */
@Data
@NoArgsConstructor
@AllArgsConstructor
public class MachineDTO {
    private String ip;
    private String port;
}

触发下线与刷新本地缓存

@GetMapping(path = "/offline")
@SuppressWarnings({"rawtypes"})
public String offlineFormService(@RequestParam String ip, String port) throws IOException, NoSuchMethodException, IllegalAccessException, InvocationTargetException,
        InterruptedException {
   // 给服务端发送请求，要求下线
    URL url = new URL("http://" + ip + ":" + port + "/quickform/shutdown");
    URLConnection connection = url.openConnection();
    connection.connect();
    String responseStr = new BufferedReader(new InputStreamReader(connection.getInputStream())).lines()
            .collect(Collectors.joining());
    String success = "ok";
    if (!success.equals(responseStr)) {
        return "下线远程服务失败";
    }

    FeignLoadBalancer feignLoadBalancer = lbClientFactory.create(InterfaceService.SERVICE_NAME);
    DynamicServerListLoadBalancer loadBalancer = (DynamicServerListLoadBalancer) feignLoadBalancer.getLoadBalancer();
    // ribbion负载均衡操作时，从balancer中获取可用的服务地址,因此可以用来判断是否更新成功
    int curAvailableCount = loadBalancer.getReachableServers().size();
    do {
        //触发下线后，不能eureka服务端信息更新也有延迟，因此需要重试
        TimeUnit.SECONDS.sleep(1);
        //更新eureka
        updateEurekaInfo();
        //调用更新ribbon环境的机器信息
        loadBalancer.updateListOfServers();
    } while (curAvailableCount == loadBalancer.getReachableServers().size());
    return "下线成功!";
}

// eureka缓存的机器信息
private void updateEurekaInfo() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
    DiscoveryClient discoveryClient = DiscoveryManager.getInstance().getDiscoveryClient();
    Method fetchRegistry = DiscoveryClient.class.getDeclaredMethod("fetchRegistry", boolean.class);
    fetchRegistry.setAccessible(true);

    fetchRegistry.invoke(discoveryClient, true);
}

总结

本文为单机测试代码，对于线上的实际情况，需要在触发服务器下线后，给所有客户端机器广播下线消息，从而让所有的客户端进行都刷新操作!!!