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本文主要研究一下HttpClientBuilder
HttpClientBuilder
httpclient-4.5.10-sources.jar!/org/apache/http/impl/client/HttpClientBuilder.java
代码语言：javascript复制public class HttpClientBuilder {
public static HttpClientBuilder create() {
return new HttpClientBuilder();
}
protected HttpClientBuilder() {
super();
}
public CloseableHttpClient build() {
// Create main request executor
// We copy the instance fields to avoid changing them, and rename to avoid accidental use of the wrong version
PublicSuffixMatcher publicSuffixMatcherCopy = this.publicSuffixMatcher;
if (publicSuffixMatcherCopy == null) {
publicSuffixMatcherCopy = PublicSuffixMatcherLoader.getDefault();
}
HttpRequestExecutor requestExecCopy = this.requestExec;
if (requestExecCopy == null) {
requestExecCopy = new HttpRequestExecutor();
}
HttpClientConnectionManager connManagerCopy = this.connManager;
if (connManagerCopy == null) {
LayeredConnectionSocketFactory sslSocketFactoryCopy = this.sslSocketFactory;
if (sslSocketFactoryCopy == null) {
final String[] supportedProtocols = systemProperties ? split(
System.getProperty("https.protocols")) : null;
final String[] supportedCipherSuites = systemProperties ? split(
System.getProperty("https.cipherSuites")) : null;
HostnameVerifier hostnameVerifierCopy = this.hostnameVerifier;
if (hostnameVerifierCopy == null) {
hostnameVerifierCopy = new DefaultHostnameVerifier(publicSuffixMatcherCopy);
}
if (sslContext != null) {
sslSocketFactoryCopy = new SSLConnectionSocketFactory(
sslContext, supportedProtocols, supportedCipherSuites, hostnameVerifierCopy);
} else {
if (systemProperties) {
sslSocketFactoryCopy = new SSLConnectionSocketFactory(
(SSLSocketFactory) SSLSocketFactory.getDefault(),
supportedProtocols, supportedCipherSuites, hostnameVerifierCopy);
} else {
sslSocketFactoryCopy = new SSLConnectionSocketFactory(
SSLContexts.createDefault(),
hostnameVerifierCopy);
}
}
}
@SuppressWarnings("resource")
final PoolingHttpClientConnectionManager poolingmgr = new PoolingHttpClientConnectionManager(
RegistryBuilder.<ConnectionSocketFactory>create()
.register("http", PlainConnectionSocketFactory.getSocketFactory())
.register("https", sslSocketFactoryCopy)
.build(),
null,
null,
dnsResolver,
connTimeToLive,
connTimeToLiveTimeUnit != null ? connTimeToLiveTimeUnit : TimeUnit.MILLISECONDS);
if (defaultSocketConfig != null) {
poolingmgr.setDefaultSocketConfig(defaultSocketConfig);
}
if (defaultConnectionConfig != null) {
poolingmgr.setDefaultConnectionConfig(defaultConnectionConfig);
}
if (systemProperties) {
String s = System.getProperty("http.keepAlive", "true");
if ("true".equalsIgnoreCase(s)) {
s = System.getProperty("http.maxConnections", "5");
final int max = Integer.parseInt(s);
poolingmgr.setDefaultMaxPerRoute(max);
poolingmgr.setMaxTotal(2 * max);
}
}
if (maxConnTotal > 0) {
poolingmgr.setMaxTotal(maxConnTotal);
}
if (maxConnPerRoute > 0) {
poolingmgr.setDefaultMaxPerRoute(maxConnPerRoute);
}
connManagerCopy = poolingmgr;
}
ConnectionReuseStrategy reuseStrategyCopy = this.reuseStrategy;
if (reuseStrategyCopy == null) {
if (systemProperties) {
final String s = System.getProperty("http.keepAlive", "true");
if ("true".equalsIgnoreCase(s)) {
reuseStrategyCopy = DefaultClientConnectionReuseStrategy.INSTANCE;
} else {
reuseStrategyCopy = NoConnectionReuseStrategy.INSTANCE;
}
} else {
reuseStrategyCopy = DefaultClientConnectionReuseStrategy.INSTANCE;
}
}
ConnectionKeepAliveStrategy keepAliveStrategyCopy = this.keepAliveStrategy;
if (keepAliveStrategyCopy == null) {
keepAliveStrategyCopy = DefaultConnectionKeepAliveStrategy.INSTANCE;
}
AuthenticationStrategy targetAuthStrategyCopy = this.targetAuthStrategy;
if (targetAuthStrategyCopy == null) {
targetAuthStrategyCopy = TargetAuthenticationStrategy.INSTANCE;
}
AuthenticationStrategy proxyAuthStrategyCopy = this.proxyAuthStrategy;
if (proxyAuthStrategyCopy == null) {
proxyAuthStrategyCopy = ProxyAuthenticationStrategy.INSTANCE;
}
UserTokenHandler userTokenHandlerCopy = this.userTokenHandler;
if (userTokenHandlerCopy == null) {
if (!connectionStateDisabled) {
userTokenHandlerCopy = DefaultUserTokenHandler.INSTANCE;
} else {
userTokenHandlerCopy = NoopUserTokenHandler.INSTANCE;
}
}
String userAgentCopy = this.userAgent;
if (userAgentCopy == null) {
if (systemProperties) {
userAgentCopy = System.getProperty("http.agent");
}
if (userAgentCopy == null && !defaultUserAgentDisabled) {
userAgentCopy = VersionInfo.getUserAgent("Apache-HttpClient",
"org.apache.http.client", getClass());
}
}
ClientExecChain execChain = createMainExec(
requestExecCopy,
connManagerCopy,
reuseStrategyCopy,
keepAliveStrategyCopy,
new ImmutableHttpProcessor(new RequestTargetHost(), new RequestUserAgent(userAgentCopy)),
targetAuthStrategyCopy,
proxyAuthStrategyCopy,
userTokenHandlerCopy);
execChain = decorateMainExec(execChain);
HttpProcessor httpprocessorCopy = this.httpprocessor;
if (httpprocessorCopy == null) {
final HttpProcessorBuilder b = HttpProcessorBuilder.create();
if (requestFirst != null) {
for (final HttpRequestInterceptor i: requestFirst) {
b.addFirst(i);
}
}
if (responseFirst != null) {
for (final HttpResponseInterceptor i: responseFirst) {
b.addFirst(i);
}
}
b.addAll(
new RequestDefaultHeaders(defaultHeaders),
new RequestContent(),
new RequestTargetHost(),
new RequestClientConnControl(),
new RequestUserAgent(userAgentCopy),
new RequestExpectContinue());
if (!cookieManagementDisabled) {
b.add(new RequestAddCookies());
}
if (!contentCompressionDisabled) {
if (contentDecoderMap != null) {
final List<String> encodings = new ArrayList<String>(contentDecoderMap.keySet());
Collections.sort(encodings);
b.add(new RequestAcceptEncoding(encodings));
} else {
b.add(new RequestAcceptEncoding());
}
}
if (!authCachingDisabled) {
b.add(new RequestAuthCache());
}
if (!cookieManagementDisabled) {
b.add(new ResponseProcessCookies());
}
if (!contentCompressionDisabled) {
if (contentDecoderMap != null) {
final RegistryBuilder<InputStreamFactory> b2 = RegistryBuilder.create();
for (final Map.Entry<String, InputStreamFactory> entry: contentDecoderMap.entrySet()) {
b2.register(entry.getKey(), entry.getValue());
}
b.add(new ResponseContentEncoding(b2.build()));
} else {
b.add(new ResponseContentEncoding());
}
}
if (requestLast != null) {
for (final HttpRequestInterceptor i: requestLast) {
b.addLast(i);
}
}
if (responseLast != null) {
for (final HttpResponseInterceptor i: responseLast) {
b.addLast(i);
}
}
httpprocessorCopy = b.build();
}
execChain = new ProtocolExec(execChain, httpprocessorCopy);
execChain = decorateProtocolExec(execChain);
// Add request retry executor, if not disabled
if (!automaticRetriesDisabled) {
HttpRequestRetryHandler retryHandlerCopy = this.retryHandler;
if (retryHandlerCopy == null) {
retryHandlerCopy = DefaultHttpRequestRetryHandler.INSTANCE;
}
execChain = new RetryExec(execChain, retryHandlerCopy);
}
HttpRoutePlanner routePlannerCopy = this.routePlanner;
if (routePlannerCopy == null) {
SchemePortResolver schemePortResolverCopy = this.schemePortResolver;
if (schemePortResolverCopy == null) {
schemePortResolverCopy = DefaultSchemePortResolver.INSTANCE;
}
if (proxy != null) {
routePlannerCopy = new DefaultProxyRoutePlanner(proxy, schemePortResolverCopy);
} else if (systemProperties) {
routePlannerCopy = new SystemDefaultRoutePlanner(
schemePortResolverCopy, ProxySelector.getDefault());
} else {
routePlannerCopy = new DefaultRoutePlanner(schemePortResolverCopy);
}
}
// Optionally, add service unavailable retry executor
final ServiceUnavailableRetryStrategy serviceUnavailStrategyCopy = this.serviceUnavailStrategy;
if (serviceUnavailStrategyCopy != null) {
execChain = new ServiceUnavailableRetryExec(execChain, serviceUnavailStrategyCopy);
}
// Add redirect executor, if not disabled
if (!redirectHandlingDisabled) {
RedirectStrategy redirectStrategyCopy = this.redirectStrategy;
if (redirectStrategyCopy == null) {
redirectStrategyCopy = DefaultRedirectStrategy.INSTANCE;
}
execChain = new RedirectExec(execChain, routePlannerCopy, redirectStrategyCopy);
}
// Optionally, add connection back-off executor
if (this.backoffManager != null && this.connectionBackoffStrategy != null) {
execChain = new BackoffStrategyExec(execChain, this.connectionBackoffStrategy, this.backoffManager);
}
Lookup<AuthSchemeProvider> authSchemeRegistryCopy = this.authSchemeRegistry;
if (authSchemeRegistryCopy == null) {
authSchemeRegistryCopy = RegistryBuilder.<AuthSchemeProvider>create()
.register(AuthSchemes.BASIC, new BasicSchemeFactory())
.register(AuthSchemes.DIGEST, new DigestSchemeFactory())
.register(AuthSchemes.NTLM, new NTLMSchemeFactory())
.register(AuthSchemes.SPNEGO, new SPNegoSchemeFactory())
.register(AuthSchemes.KERBEROS, new KerberosSchemeFactory())
.build();
}
Lookup<CookieSpecProvider> cookieSpecRegistryCopy = this.cookieSpecRegistry;
if (cookieSpecRegistryCopy == null) {
cookieSpecRegistryCopy = CookieSpecRegistries.createDefault(publicSuffixMatcherCopy);
}
CookieStore defaultCookieStore = this.cookieStore;
if (defaultCookieStore == null) {
defaultCookieStore = new BasicCookieStore();
}
CredentialsProvider defaultCredentialsProvider = this.credentialsProvider;
if (defaultCredentialsProvider == null) {
if (systemProperties) {
defaultCredentialsProvider = new SystemDefaultCredentialsProvider();
} else {
defaultCredentialsProvider = new BasicCredentialsProvider();
}
}
List<Closeable> closeablesCopy = closeables != null ? new ArrayList<Closeable>(closeables) : null;
if (!this.connManagerShared) {
if (closeablesCopy == null) {
closeablesCopy = new ArrayList<Closeable>(1);
}
final HttpClientConnectionManager cm = connManagerCopy;
if (evictExpiredConnections || evictIdleConnections) {
final IdleConnectionEvictor connectionEvictor = new IdleConnectionEvictor(cm,
maxIdleTime > 0 ? maxIdleTime : 10, maxIdleTimeUnit != null ? maxIdleTimeUnit : TimeUnit.SECONDS,
maxIdleTime, maxIdleTimeUnit);
closeablesCopy.add(new Closeable() {
@Override
public void close() throws IOException {
connectionEvictor.shutdown();
try {
connectionEvictor.awaitTermination(1L, TimeUnit.SECONDS);
} catch (final InterruptedException interrupted) {
Thread.currentThread().interrupt();
}
}
});
connectionEvictor.start();
}
closeablesCopy.add(new Closeable() {
@Override
public void close() throws IOException {
cm.shutdown();
}
});
}
return new InternalHttpClient(
execChain,
connManagerCopy,
routePlannerCopy,
cookieSpecRegistryCopy,
authSchemeRegistryCopy,
defaultCookieStore,
defaultCredentialsProvider,
defaultRequestConfig != null ? defaultRequestConfig : RequestConfig.DEFAULT,
closeablesCopy);
}
}HttpClientBuilder提供了静态方法create用于创建builder，其build方法用于创建CloseableHttpClient，它主要是构建ClientExecChain(
HttpRequestExecutor、HttpClientConnectionManager、ConnectionReuseStrategy、ConnectionKeepAliveStrategy、AuthenticationStrategy、UserTokenHandler)、ProtocolExec(ClientExecChain、HttpProcessor)、RetryExec(ClientExecChain、HttpRequestRetryHandler)、RedirectExec(HttpRoutePlanner、ServiceUnavailableRetryStrategy、RedirectStrategy)、BackoffStrategyExec；最后构建的是InternalHttpClient
SSLContext
org/apache/http/ssl/SSLContexts.java 对于sslContext不为null的则创建SSLConnectionSocketFactory(sslContext, supportedProtocols, supportedCipherSuites, hostnameVerifierCopy)，为null的话，则通过SSLContexts.createDefault()来创建默认的SSLContext
代码语言：javascript复制public static SSLContext createDefault() throws SSLInitializationException {
try {
final SSLContext sslContext = SSLContext.getInstance(SSLContextBuilder.TLS);
sslContext.init(null, null, null);
return sslContext;
} catch (final NoSuchAlgorithmException ex) {
throw new SSLInitializationException(ex.getMessage(), ex);
} catch (final KeyManagementException ex) {
throw new SSLInitializationException(ex.getMessage(), ex);
}
}HostnameVerifier
若hostnameVerifier为null，则创建默认的DefaultHostnameVerifier
代码语言：javascript复制public DefaultHostnameVerifier(final PublicSuffixMatcher publicSuffixMatcher) {
this.publicSuffixMatcher = publicSuffixMatcher;
}
public DefaultHostnameVerifier() {
this(null);
}
@Override
public boolean verify(final String host, final SSLSession session) {
try {
final Certificate[] certs = session.getPeerCertificates();
final X509Certificate x509 = (X509Certificate) certs[0];
verify(host, x509);
return true;
} catch (final SSLException ex) {
if (log.isDebugEnabled()) {
log.debug(ex.getMessage(), ex);
}
return false;
}
}PoolingHttpClientConnectionManager
org/apache/http/impl/conn/PoolingHttpClientConnectionManager.java
代码语言：javascript复制@Contract(threading = ThreadingBehavior.SAFE_CONDITIONAL)
public class PoolingHttpClientConnectionManager
implements HttpClientConnectionManager, ConnPoolControl<HttpRoute>, Closeable {
private final ConfigData configData;
private final CPool pool;
private final HttpClientConnectionOperator connectionOperator;
private final AtomicBoolean isShutDown;
public PoolingHttpClientConnectionManager(
final HttpClientConnectionOperator httpClientConnectionOperator,
final HttpConnectionFactory<HttpRoute, ManagedHttpClientConnection> connFactory,
final long timeToLive, final TimeUnit timeUnit) {
super();
this.configData = new ConfigData();
this.pool = new CPool(new InternalConnectionFactory(
this.configData, connFactory), 2, 20, timeToLive, timeUnit);
this.pool.setValidateAfterInactivity(2000);
this.connectionOperator = Args.notNull(httpClientConnectionOperator, "HttpClientConnectionOperator");
this.isShutDown = new AtomicBoolean(false);
}
@Override
protected void finalize() throws Throwable {
try {
shutdown();
} finally {
super.finalize();
}
}
@Override
public void close() {
shutdown();
}
//......
} PoolingHttpClientConnectionManager实现了HttpClientConnectionManager、ConnPoolControl、Closeable接口，它使用了CPool作为连接池来管理连接，默认的maxPerRoute为2，maxTotal为20
小结
apache的httpclient的HttpClientBuilder提供了构建CloseableHttpClient的方法，它提供了设置sslContext的方法，如果没有设置则通过SSLContexts.createDefault()来创建默认的SSLContext，若hostnameVerifier为null，则创建默认的DefaultHostnameVerifier，其默认会创建HttpClientConnectionManager，使用的是maxPerRoute为2，maxTotal为20的连接池。
