这篇文章主要介绍“nacos client中ServerHttpAgent的原理和使用方法”，在日常操作中，相信很多人在nacos client中ServerHttpAgent的原理和使用方法问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答”nacos client中ServerHttpAgent的原理和使用方法”的疑惑有所帮助！接下来，请跟着小编一起来学习吧！
本文主要研究一下nacos client的ServerHttpAgent
nacos-1.1.3/client/src/main/java/com/alibaba/nacos/client/config/http/HttpAgent.java
public interface HttpAgent { /** * start to get nacos ip list * @return Nothing. * @throws NacosException on get ip list error. */ void start() throws NacosException; /** * invoke http get method * @param path http path * @param headers http headers * @param paramValues http paramValues http * @param encoding http encode * @param readTimeoutMs http timeout * @return HttpResult http response * @throws IOException If an input or output exception occurred */ HttpResult httpGet(String path, List<String> headers, List<String> paramValues, String encoding, long readTimeoutMs) throws IOException; /** * invoke http post method * @param path http path * @param headers http headers * @param paramValues http paramValues http * @param encoding http encode * @param readTimeoutMs http timeout * @return HttpResult http response * @throws IOException If an input or output exception occurred */ HttpResult httpPost(String path, List<String> headers, List<String> paramValues, String encoding, long readTimeoutMs) throws IOException; /** * invoke http delete method * @param path http path * @param headers http headers * @param paramValues http paramValues http * @param encoding http encode * @param readTimeoutMs http timeout * @return HttpResult http response * @throws IOException If an input or output exception occurred */ HttpResult httpDelete(String path, List<String> headers, List<String> paramValues, String encoding, long readTimeoutMs) throws IOException; /** * get name * @return String */ String getName(); /** * get namespace * @return String */ String getNamespace(); /** * get tenant * @return String */ String getTenant(); /** * get encode * @return String */ String getEncode(); }HttpAgent定义了start、httpGet、httpPost、httpDelete、getName、getNamespace、getTenant、getEncode方法
nacos-1.1.3/client/src/main/java/com/alibaba/nacos/client/config/http/ServerHttpAgent.java
public class ServerHttpAgent implements HttpAgent { private static final Logger LOGGER = LogUtils.logger(ServerHttpAgent.class); /** * @param path 相对于web应用根，以/开头 * @param headers * @param paramValues * @param encoding * @param readTimeoutMs * @return * @throws IOException */ @Override public HttpResult httpGet(String path, List<String> headers, List<String> paramValues, String encoding, long readTimeoutMs) throws IOException { final long endTime = System.currentTimeMillis() + readTimeoutMs; final boolean isSSL = false; String currentServerAddr = serverListMgr.getCurrentServerAddr(); int maxRetry = this.maxRetry; do { try { List<String> newHeaders = getSpasHeaders(paramValues); if (headers != null) { newHeaders.addAll(headers); } HttpResult result = HttpSimpleClient.httpGet( getUrl(currentServerAddr, path), newHeaders, paramValues, encoding, readTimeoutMs, isSSL); if (result.code == HttpURLConnection.HTTP_INTERNAL_ERROR || result.code == HttpURLConnection.HTTP_BAD_GATEWAY || result.code == HttpURLConnection.HTTP_UNAVAILABLE) { LOGGER.error("[NACOS ConnectException] currentServerAddr: {}, httpCode: {}", serverListMgr.getCurrentServerAddr(), result.code); } else { // Update the currently available server addr serverListMgr.updateCurrentServerAddr(currentServerAddr); return result; } } catch (ConnectException ce) { LOGGER.error("[NACOS ConnectException httpGet] currentServerAddr:{}, err : {}", serverListMgr.getCurrentServerAddr(), ce.getMessage()); } catch (SocketTimeoutException stoe) { LOGGER.error("[NACOS SocketTimeoutException httpGet] currentServerAddr:{}， err : {}", serverListMgr.getCurrentServerAddr(), stoe.getMessage()); } catch (IOException ioe) { LOGGER.error("[NACOS IOException httpGet] currentServerAddr: " + serverListMgr.getCurrentServerAddr(), ioe); throw ioe; } if (serverListMgr.getIterator().hasNext()) { currentServerAddr = serverListMgr.getIterator().next(); } else { maxRetry --; if (maxRetry < 0) { throw new ConnectException("[NACOS HTTP-GET] The maximum number of tolerable server reconnection errors has been reached"); } serverListMgr.refreshCurrentServerAddr(); } } while (System.currentTimeMillis() <= endTime); LOGGER.error("no available server"); throw new ConnectException("no available server"); } @Override public HttpResult httpPost(String path, List<String> headers, List<String> paramValues, String encoding, long readTimeoutMs) throws IOException { final long endTime = System.currentTimeMillis() + readTimeoutMs; boolean isSSL = false; String currentServerAddr = serverListMgr.getCurrentServerAddr(); int maxRetry = this.maxRetry; do { try { List<String> newHeaders = getSpasHeaders(paramValues); if (headers != null) { newHeaders.addAll(headers); } HttpResult result = HttpSimpleClient.httpPost( getUrl(currentServerAddr, path), newHeaders, paramValues, encoding, readTimeoutMs, isSSL); if (result.code == HttpURLConnection.HTTP_INTERNAL_ERROR || result.code == HttpURLConnection.HTTP_BAD_GATEWAY || result.code == HttpURLConnection.HTTP_UNAVAILABLE) { LOGGER.error("[NACOS ConnectException] currentServerAddr: {}, httpCode: {}", currentServerAddr, result.code); } else { // Update the currently available server addr serverListMgr.updateCurrentServerAddr(currentServerAddr); return result; } } catch (ConnectException ce) { LOGGER.error("[NACOS ConnectException httpPost] currentServerAddr: {}, err : {}", currentServerAddr, ce.getMessage()); } catch (SocketTimeoutException stoe) { LOGGER.error("[NACOS SocketTimeoutException httpPost] currentServerAddr: {}， err : {}", currentServerAddr, stoe.getMessage()); } catch (IOException ioe) { LOGGER.error("[NACOS IOException httpPost] currentServerAddr: " + currentServerAddr, ioe); throw ioe; } if (serverListMgr.getIterator().hasNext()) { currentServerAddr = serverListMgr.getIterator().next(); } else { maxRetry --; if (maxRetry < 0) { throw new ConnectException("[NACOS HTTP-POST] The maximum number of tolerable server reconnection errors has been reached"); } serverListMgr.refreshCurrentServerAddr(); } } while (System.currentTimeMillis() <= endTime); LOGGER.error("no available server, currentServerAddr : {}", currentServerAddr); throw new ConnectException("no available server, currentServerAddr : " + currentServerAddr); } //...... }ServerHttpAgent实现了HttpAgent接口，其httpGet、httpPost、httpDelete方法的结构大体相同，都是以do while做循环，循环条件为距离开始执行时间不超过readTimeoutMs
循环开始之前会通过serverListMgr.getCurrentServerAddr()方法获取currentServerAddr，循环体内则通过HttpSimpleClient的相应方法执行请求，如果返回的HTTP Code为HTTP_INTERNAL_ERROR、HTTP_BAD_GATEWAY、HTTP_UNAVAILABLE则打印error日志，否则执行serverListMgr.updateCurrentServerAddr(currentServerAddr)，然后返回
如果出现异常或者没有提前返回，则判断serverListMgr.getIterator().hasNext()，如果为true则使用serverListMgr.getIterator().next()更新currentServerAddr，为false则递减maxRetry，然后执行serverListMgr.refreshCurrentServerAddr()
ServerHttpAgent实现了HttpAgent接口，其httpGet、httpPost、httpDelete方法的结构大体相同，都是以do while做循环，循环条件为距离开始执行时间不超过readTimeoutMs
到此，关于“nacos client中ServerHttpAgent的原理和使用方法”的学习就结束了，希望能够解决大家的疑惑。理论与实践的搭配能更好的帮助大家学习，快去试试吧！若想继续学习更多相关知识，请继续关注亿速云网站，小编会继续努力为大家带来更多实用的文章！
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