这篇文章主要讲解了“SpringCloud Feign中怎么使用ApacheHttpClient代替默认client方式”，文中的讲解内容简单清晰，易于学习与理解，下面请大家跟着小编的思路慢慢深入，一起来研究和学习“SpringCloud Feign中怎么使用ApacheHttpClient代替默认client方式”吧！
使用ApacheHttpClient代替默认client
ApacheHttpClient和默认实现的比较
Feign在默认情况下使用的是JDK原生的URLConnection发送HTTP请求，没有连接池，但是对每个地址会保持一个长连接，即利用HTTP的persistence connection。
ApacheHttpClient实现了连接池，同时它封装了访问http的请求头，参数，内容体，响应等等，使客户端发送 HTTP 请求变得容易。
ApacheHttpClient 使用
maven 依赖
<dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-openfeign</artifactId> </dependency> <dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> <version>4.5.7</version> </dependency> <dependency> <groupId>io.github.openfeign</groupId> <artifactId>feign-httpclient</artifactId> <version>10.1.0</version> </dependency>配置文件的修改
feign: httpclient: enabled: true创建ApacheHttpClient客户端
import javax.net.ssl.SSLContext;import lombok.extern.slf4j.Slf4j;import org.apache.http.conn.ssl.SSLConnectionSocketFactory;import org.apache.http.impl.client.CloseableHttpClient;import org.apache.http.impl.client.HttpClients;import org.apache.http.ssl.SSLContextBuilder;import org.apache.http.ssl.SSLContexts;import org.springframework.util.ResourceUtils;import feign.httpclient.ApacheHttpClient;@Slf4jpublic class FeignClientBuilder { private boolean enabled; private String keyPassword; private String keyStore; private String keyStorePassword; private String trustStore; private String trustStorePassword; private int maxConnTotal = 2048; private int maxConnPerRoute = 512; public FeignClientBuilder(boolean enabled, String keyPassword, String keyStore, String keyStorePassword, String trustStore, String trustStorePassword, int maxConnTotal, int maxConnPerRoute) { this.enabled = enabled; this.keyPassword = keyPassword; this.keyStore = keyStore; this.keyStorePassword = keyStorePassword; this.trustStore = trustStore; this.trustStorePassword = trustStorePassword; this.maxConnTotal = maxConnTotal; this.maxConnPerRoute = maxConnPerRoute; } public ApacheHttpClient apacheHttpClient() { CloseableHttpClient defaultHttpClient = HttpClients.custom() .setMaxConnTotal(maxConnTotal) .setMaxConnPerRoute(maxConnPerRoute) .build(); ApacheHttpClient defaultApacheHttpClient = new ApacheHttpClient(defaultHttpClient); if (!enabled) { return defaultApacheHttpClient; } SSLContextBuilder sslContextBuilder = SSLContexts.custom(); // 如果 服务端启用了 TLS 客户端验证，则需要指定 keyStore if (keyStore == null || keyStore.isEmpty()) { return new ApacheHttpClient(); } else { try { sslContextBuilder .loadKeyMaterial( ResourceUtils.getFile(keyStore), keyStorePassword.toCharArray(), keyPassword.toCharArray()); } catch (Exception e) { e.printStackTrace(); } } // 如果 https 使用自签名证书，则需要指定 trustStore if (trustStore == null || trustStore.isEmpty()) { } else { try { sslContextBuilder// .loadTrustMaterial(TrustAllStrategy.INSTANCE) .loadTrustMaterial( ResourceUtils.getFile(trustStore), trustStorePassword.toCharArray() ); } catch (Exception e) { e.printStackTrace(); } } try { SSLContext sslContext = sslContextBuilder.build(); SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory( sslContext, SSLConnectionSocketFactory.getDefaultHostnameVerifier()); CloseableHttpClient httpClient = HttpClients.custom() .setMaxConnTotal(maxConnTotal) .setMaxConnPerRoute(maxConnPerRoute) .setSSLSocketFactory(sslsf) .build(); ApacheHttpClient apacheHttpClient = new ApacheHttpClient(httpClient); log.info("feign Client load with ssl."); return apacheHttpClient; } catch (Exception e) { e.printStackTrace(); } return defaultApacheHttpClient; } public static FeignClientBuilderBuilder builder() { return new FeignClientBuilderBuilder(); } public static class FeignClientBuilderBuilder { private boolean enabled; private String keyPassword; private String keyStore; private String keyStorePassword; private String trustStore; private String trustStorePassword; private int maxConnTotal = 2048; private int maxConnPerRoute = 512; public FeignClientBuilderBuilder enabled(boolean enabled) { this.enabled = enabled; return this; } public FeignClientBuilderBuilder keyPassword(String keyPassword) { this.keyPassword = keyPassword; return this; } public FeignClientBuilderBuilder keyStore(String keyStore) { this.keyStore = keyStore; return this; } public FeignClientBuilderBuilder keyStorePassword(String keyStorePassword) { this.keyStorePassword = keyStorePassword; return this; } public FeignClientBuilderBuilder trustStore(String trustStore) { this.trustStore = trustStore; return this; } public FeignClientBuilderBuilder trustStorePassword(String trustStorePassword) { this.trustStorePassword = trustStorePassword; return this; } public FeignClientBuilderBuilder maxConnTotal(int maxConnTotal) { this.maxConnTotal = maxConnTotal; return this; } public FeignClientBuilderBuilder maxConnPerRoute(int maxConnPerRoute) { this.maxConnPerRoute = maxConnPerRoute; return this; } public FeignClientBuilder build() { return new FeignClientBuilder( this.enabled, this.keyPassword, this.keyStore, this.keyStorePassword, this.trustStore, this.trustStorePassword, this.maxConnTotal, this.maxConnPerRoute ); } }}
使用时可以直接使用builder来创建ApacheHttpClient。
apache的HttpClient的默认重试机制
maven
<dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> <version>4.5.2</version> </dependency>异常重试log
2017-01-31 19:31:39.057 INFO 3873 --- [askScheduler-13] o.apache.http.impl.execchain.RetryExec : I/O exception (org.apache.http.NoHttpResponseException) caught when processing request to {}->http://192.168.99.100:8080: The target server failed to respond
2017-01-31 19:31:39.058 INFO 3873 --- [askScheduler-13] o.apache.http.impl.execchain.RetryExec : Retrying request to {}->http://192.168.99.100:8080
RetryExec
org/apache/http/impl/execchain/RetryExec.java
@Immutablepublic class RetryExec implements ClientExecChain { private final Log log = LogFactory.getLog(getClass()); private final ClientExecChain requestExecutor; private final HttpRequestRetryHandler retryHandler; public RetryExec( final ClientExecChain requestExecutor, final HttpRequestRetryHandler retryHandler) { Args.notNull(requestExecutor, "HTTP request executor"); Args.notNull(retryHandler, "HTTP request retry handler"); this.requestExecutor = requestExecutor; this.retryHandler = retryHandler; } @Override public CloseableHttpResponse execute( final HttpRoute route, final HttpRequestWrapper request, final HttpClientContext context, final HttpExecutionAware execAware) throws IOException, HttpException { Args.notNull(route, "HTTP route"); Args.notNull(request, "HTTP request"); Args.notNull(context, "HTTP context"); final Header[] origheaders = request.getAllHeaders(); for (int execCount = 1;; execCount++) { try { return this.requestExecutor.execute(route, request, context, execAware); } catch (final IOException ex) { if (execAware != null && execAware.isAborted()) { this.log.debug("Request has been aborted"); throw ex; } if (retryHandler.retryRequest(ex, execCount, context)) { if (this.log.isInfoEnabled()) { this.log.info("I/O exception ("+ ex.getClass().getName() + ") caught when processing request to " + route + ": " + ex.getMessage()); } if (this.log.isDebugEnabled()) { this.log.debug(ex.getMessage(), ex); } if (!RequestEntityProxy.isRepeatable(request)) { this.log.debug("Cannot retry non-repeatable request"); throw new NonRepeatableRequestException("Cannot retry request " + "with a non-repeatable request entity", ex); } request.setHeaders(origheaders); if (this.log.isInfoEnabled()) { this.log.info("Retrying request to " + route); } } else { if (ex instanceof NoHttpResponseException) { final NoHttpResponseException updatedex = new NoHttpResponseException( route.getTargetHost().toHostString() + " failed to respond"); updatedex.setStackTrace(ex.getStackTrace()); throw updatedex; } else { throw ex; } } } } }}DefaultHttpRequestRetryHandler
org/apache/http/impl/client/DefaultHttpRequestRetryHandler.java
@Immutablepublic class DefaultHttpRequestRetryHandler implements HttpRequestRetryHandler { public static final DefaultHttpRequestRetryHandler INSTANCE = new DefaultHttpRequestRetryHandler(); private final int retryCount; private final boolean requestSentRetryEnabled; private final Set<Class<? extends IOException>> nonRetriableClasses; protected DefaultHttpRequestRetryHandler( final int retryCount, final boolean requestSentRetryEnabled, final Collection<Class<? extends IOException>> clazzes) { super(); this.retryCount = retryCount; this.requestSentRetryEnabled = requestSentRetryEnabled; this.nonRetriableClasses = new HashSet<Class<? extends IOException>>(); for (final Class<? extends IOException> clazz: clazzes) { this.nonRetriableClasses.add(clazz); } } @SuppressWarnings("unchecked") public DefaultHttpRequestRetryHandler(final int retryCount, final boolean requestSentRetryEnabled) { this(retryCount, requestSentRetryEnabled, Arrays.asList( InterruptedIOException.class, UnknownHostException.class, ConnectException.class, SSLException.class)); } public DefaultHttpRequestRetryHandler() { this(3, false); } @Override public boolean retryRequest( final IOException exception, final int executionCount, final HttpContext context) { Args.notNull(exception, "Exception parameter"); Args.notNull(context, "HTTP context"); if (executionCount > this.retryCount) { // Do not retry if over max retry count return false; } if (this.nonRetriableClasses.contains(exception.getClass())) { return false; } else { for (final Class<? extends IOException> rejectException : this.nonRetriableClasses) { if (rejectException.isInstance(exception)) { return false; } } } final HttpClientContext clientContext = HttpClientContext.adapt(context); final HttpRequest request = clientContext.getRequest(); if(requestIsAborted(request)){ return false; } if (handleAsIdempotent(request)) { // Retry if the request is considered idempotent return true; } if (!clientContext.isRequestSent() || this.requestSentRetryEnabled) { // Retry if the request has not been sent fully or // if it's OK to retry methods that have been sent return true; } // otherwise do not retry return false; } public boolean isRequestSentRetryEnabled() { return requestSentRetryEnabled; } public int getRetryCount() { return retryCount; } protected boolean handleAsIdempotent(final HttpRequest request) { return !(request instanceof HttpEntityEnclosingRequest); } @Deprecated protected boolean requestIsAborted(final HttpRequest request) { HttpRequest req = request; if (request instanceof RequestWrapper) { // does not forward request to original req = ((RequestWrapper) request).getOriginal(); } return (req instanceof HttpUriRequest && ((HttpUriRequest)req).isAborted()); }}默认重试3次，三次都失败则抛出NoHttpResponseException或其他异常
感谢各位的阅读，以上就是“SpringCloud Feign中怎么使用ApacheHttpClient代替默认client方式”的内容了，经过本文的学习后，相信大家对SpringCloud Feign中怎么使用ApacheHttpClient代替默认client方式这一问题有了更深刻的体会，具体使用情况还需要大家实践验证。这里是编程网，小编将为大家推送更多相关知识点的文章，欢迎关注！
