畢竟第一篇，客氣一下，隨便說一句。之後會直接上源碼，並加註釋。
關於EurekaClientConfigBean爲什麼要解析這個類，因爲跟註冊服務的配置項息息相關。
好吧 我承認我挺懶的。這些配置項其實都是可以通過配置文件覆寫缺省值，下面貼代碼，英文懶得翻譯了。太多，當字典用吧
/**
* @author Dave Syer
* @author Gregor Zurowski
*/
@ConfigurationProperties(EurekaClientConfigBean.PREFIX)
public class EurekaClientConfigBean implements EurekaClientConfig {
//客戶端配置前綴
public static final String PREFIX = "eureka.client";
//有時候總是會報錯並且展示localhost:8761啓動失敗，在這，默認url，DEFAULT_PREFIX默認值是：/eureka。
public static final String DEFAULT_URL = "http://localhost:8761" + DEFAULT_PREFIX
+ "/";
//默認域
public static final String DEFAULT_ZONE = "defaultZone";
private static final int MINUTES = 60;
@Autowired(required = false)
PropertyResolver propertyResolver;
/**
* eureka客戶端聲明開啓，默認開啓
*/
private boolean enabled = true;
@NestedConfigurationProperty
private EurekaTransportConfig transport = new CloudEurekaTransportConfig();
/**
* 用來聲明，多長時間從註冊中心服務端拉取一次服務信息，單位秒；這個就是主動拉取註冊中心上所有服務的實例信息。
*/
private int registryFetchIntervalSeconds = 30;
/**
* 用來聲明，多長時間複製實例變化到eureka服務端，單位秒；這個配置是複製實例信息到註冊中心
*/
private int instanceInfoReplicationIntervalSeconds = 30;
/**
* 用來聲明實例初始化複製信息到eureka服務端的間隔時間，所以可以看到，其實實例的初始化階段不是立即複製實例信息到註冊中心的，單位秒；
*/
private int initialInstanceInfoReplicationIntervalSeconds = 40;
/**
* 用來聲明eureka服務端的變化，多長時間，客戶端會獲取一次eureka服務的信息
*/
private int eurekaServiceUrlPollIntervalSeconds = 5 * MINUTES;
/**
* Gets the proxy port to eureka server if any.
*/
private String proxyPort;
/**
* Gets the proxy host to eureka server if any.
*/
private String proxyHost;
/**
* Gets the proxy user name if any.
*/
private String proxyUserName;
/**
* Gets the proxy password if any.
*/
private String proxyPassword;
/**
* Indicates how long to wait (in seconds) before a read from eureka server needs to
* timeout.
*/
private int eurekaServerReadTimeoutSeconds = 8;
/**
* Indicates how long to wait (in seconds) before a connection to eureka server needs
* to timeout. Note that the connections in the client are pooled by
* org.apache.http.client.HttpClient and this setting affects the actual connection
* creation and also the wait time to get the connection from the pool.
*/
private int eurekaServerConnectTimeoutSeconds = 5;
/**
* Gets the name of the implementation which implements BackupRegistry to fetch the
* registry information as a fall back option for only the first time when the eureka
* client starts.
*
* This may be needed for applications which needs additional resiliency for registry
* information without which it cannot operate.
*/
private String backupRegistryImpl;
/**
* Gets the total number of connections that is allowed from eureka client to all
* eureka servers.
*/
private int eurekaServerTotalConnections = 200;
/**
* Gets the total number of connections that is allowed from eureka client to a eureka
* server host.
*/
private int eurekaServerTotalConnectionsPerHost = 50;
/**
* Gets the URL context to be used to construct the service url to contact eureka
* server when the list of eureka servers come from the DNS. This information is not
* required if the contract returns the service urls from eurekaServerServiceUrls.
*
* The DNS mechanism is used when useDnsForFetchingServiceUrls is set to true and the
* eureka client expects the DNS to configured a certain way so that it can fetch
* changing eureka servers dynamically. The changes are effective at runtime.
*/
private String eurekaServerURLContext;
/**
* Gets the port to be used to construct the service url to contact eureka server when
* the list of eureka servers come from the DNS.This information is not required if
* the contract returns the service urls eurekaServerServiceUrls(String).
*
* The DNS mechanism is used when useDnsForFetchingServiceUrls is set to true and the
* eureka client expects the DNS to configured a certain way so that it can fetch
* changing eureka servers dynamically.
*
* The changes are effective at runtime.
*/
private String eurekaServerPort;
/**
* Gets the DNS name to be queried to get the list of eureka servers.This information
* is not required if the contract returns the service urls by implementing
* serviceUrls.
*
* The DNS mechanism is used when useDnsForFetchingServiceUrls is set to true and the
* eureka client expects the DNS to configured a certain way so that it can fetch
* changing eureka servers dynamically.
*
* The changes are effective at runtime.
*/
private String eurekaServerDNSName;
/**
* Gets the region (used in AWS datacenters) where this instance resides.
*/
private String region = "us-east-1";
/**
* Indicates how much time (in seconds) that the HTTP connections to eureka server can
* stay idle before it can be closed.
*
* In the AWS environment, it is recommended that the values is 30 seconds or less,
* since the firewall cleans up the connection information after a few mins leaving
* the connection hanging in limbo
*/
private int eurekaConnectionIdleTimeoutSeconds = 30;
/**
* Indicates whether the client is only interested in the registry information for a
* single VIP.
*/
private String registryRefreshSingleVipAddress;
/**
* The thread pool size for the heartbeatExecutor to initialise with
*/
private int heartbeatExecutorThreadPoolSize = 2;
/**
* Heartbeat executor exponential back off related property. It is a maximum
* multiplier value for retry delay, in case where a sequence of timeouts occurred.
*/
private int heartbeatExecutorExponentialBackOffBound = 10;
/**
* The thread pool size for the cacheRefreshExecutor to initialise with
*/
private int cacheRefreshExecutorThreadPoolSize = 2;
/**
* Cache refresh executor exponential back off related property. It is a maximum
* multiplier value for retry delay, in case where a sequence of timeouts occurred.
*/
private int cacheRefreshExecutorExponentialBackOffBound = 10;
/**
* Map of availability zone to list of fully qualified URLs to communicate with eureka
* server. Each value can be a single URL or a comma separated list of alternative
* locations.
*
* Typically the eureka server URLs carry protocol,host,port,context and version
* information if any. Example:
* http://ec2-256-156-243-129.compute-1.amazonaws.com:7001/eureka/
*
* The changes are effective at runtime at the next service url refresh cycle as
* specified by eurekaServiceUrlPollIntervalSeconds.
*/
private Map<String, String> serviceUrl = new HashMap<>();
{
this.serviceUrl.put(DEFAULT_ZONE, DEFAULT_URL);
}
/**
* Indicates whether the content fetched from eureka server has to be compressed
* whenever it is supported by the server. The registry information from the eureka
* server is compressed for optimum network traffic.
*/
private boolean gZipContent = true;
/**
* Indicates whether the eureka client should use the DNS mechanism to fetch a list of
* eureka servers to talk to. When the DNS name is updated to have additional servers,
* that information is used immediately after the eureka client polls for that
* information as specified in eurekaServiceUrlPollIntervalSeconds.
*
* Alternatively, the service urls can be returned serviceUrls, but the users should
* implement their own mechanism to return the updated list in case of changes.
*
* The changes are effective at runtime.
*/
private boolean useDnsForFetchingServiceUrls = false;
/**
* Indicates whether or not this instance should register its information with eureka
* server for discovery by others.
*
* In some cases, you do not want your instances to be discovered whereas you just
* want do discover other instances.
*/
private boolean registerWithEureka = true;
/**
* Indicates whether or not this instance should try to use the eureka server in the
* same zone for latency and/or other reason.
*
* Ideally eureka clients are configured to talk to servers in the same zone
*
* The changes are effective at runtime at the next registry fetch cycle as specified
* by registryFetchIntervalSeconds
*/
private boolean preferSameZoneEureka = true;
/**
* Indicates whether to log differences between the eureka server and the eureka
* client in terms of registry information.
*
* Eureka client tries to retrieve only delta changes from eureka server to minimize
* network traffic. After receiving the deltas, eureka client reconciles the
* information from the server to verify it has not missed out some information.
* Reconciliation failures could happen when the client has had network issues
* communicating to server.If the reconciliation fails, eureka client gets the full
* registry information.
*
* While getting the full registry information, the eureka client can log the
* differences between the client and the server and this setting controls that.
*
* The changes are effective at runtime at the next registry fetch cycle as specified
* by registryFetchIntervalSecondsr
*/
private boolean logDeltaDiff;
/**
* Indicates whether the eureka client should disable fetching of delta and should
* rather resort to getting the full registry information.
*
* Note that the delta fetches can reduce the traffic tremendously, because the rate
* of change with the eureka server is normally much lower than the rate of fetches.
*
* The changes are effective at runtime at the next registry fetch cycle as specified
* by registryFetchIntervalSeconds
*/
private boolean disableDelta;
/**
* Comma separated list of regions for which the eureka registry information will be
* fetched. It is mandatory to define the availability zones for each of these regions
* as returned by availabilityZones. Failing to do so, will result in failure of
* discovery client startup.
*
*/
private String fetchRemoteRegionsRegistry;
/**
* Gets the list of availability zones (used in AWS data centers) for the region in
* which this instance resides.
*
* The changes are effective at runtime at the next registry fetch cycle as specified
* by registryFetchIntervalSeconds.
*/
private Map<String, String> availabilityZones = new HashMap<>();
/**
* Indicates whether to get the applications after filtering the applications for
* instances with only InstanceStatus UP states.
*/
private boolean filterOnlyUpInstances = true;
/**
* Indicates whether this client should fetch eureka registry information from eureka
* server.
*/
private boolean fetchRegistry = true;
/**
* Get a replacement string for Dollar sign <code>$</code> during
* serializing/deserializing information in eureka server.
*/
private String dollarReplacement = "_-";
/**
* Get a replacement string for underscore sign <code>_</code> during
* serializing/deserializing information in eureka server.
*/
private String escapeCharReplacement = "__";
/**
* Indicates whether server can redirect a client request to a backup server/cluster.
* If set to false, the server will handle the request directly, If set to true, it
* may send HTTP redirect to the client, with a new server location.
*/
private boolean allowRedirects = false;
/**
* If set to true, local status updates via ApplicationInfoManager will trigger
* on-demand (but rate limited) register/updates to remote eureka servers
*/
private boolean onDemandUpdateStatusChange = true;
/**
* This is a transient config and once the latest codecs are stable, can be removed
* (as there will only be one)
*/
private String encoderName;
/**
* This is a transient config and once the latest codecs are stable, can be removed
* (as there will only be one)
*/
private String decoderName;
/**
* EurekaAccept name for client data accept
*/
private String clientDataAccept = EurekaAccept.full.name();
/**
* Indicates whether the client should explicitly unregister itself from the remote server
* on client shutdown.
*/
private boolean shouldUnregisterOnShutdown = true;
/**
* 客戶端初始化階段強制註冊，默認關閉
*/
private boolean shouldEnforceRegistrationAtInit = false;
}