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本文主要研究一下AsyncHttpClient的默认配置
maven
代码语言：javascript复制 <dependency>
<groupId>org.asynchttpclient</groupId>
<artifactId>async-http-client</artifactId>
<version>2.2.0</version>
</dependency>AsyncHttpClientConfig
org/asynchttpclient/AsyncHttpClientConfig.java
代码语言：javascript复制public interface AsyncHttpClientConfig {
/**
* @return the version of AHC
*/
String getAhcVersion();
/**
* Return the name of {@link AsyncHttpClient}, which is used for thread naming and debugging.
*
* @return the name.
*/
String getThreadPoolName();
/**
* Return the maximum number of connections an {@link AsyncHttpClient} can handle.
*
* @return the maximum number of connections an {@link AsyncHttpClient} can handle.
*/
int getMaxConnections();
/**
* Return the maximum number of connections per hosts an {@link AsyncHttpClient} can handle.
*
* @return the maximum number of connections per host an {@link AsyncHttpClient} can handle.
*/
int getMaxConnectionsPerHost();
/**
* Return the maximum time in millisecond an {@link AsyncHttpClient} can wait when connecting to a remote host
*
* @return the maximum time in millisecond an {@link AsyncHttpClient} can wait when connecting to a remote host
*/
int getConnectTimeout();
/**
* Return the maximum time in millisecond an {@link AsyncHttpClient} can stay idle.
*
* @return the maximum time in millisecond an {@link AsyncHttpClient} can stay idle.
*/
int getReadTimeout();
/**
* Return the maximum time in millisecond an {@link AsyncHttpClient} will keep connection in pool.
*
* @return the maximum time in millisecond an {@link AsyncHttpClient} will keep connection in pool.
*/
int getPooledConnectionIdleTimeout();
/**
* @return the period in millis to clean the pool of dead and idle connections.
*/
int getConnectionPoolCleanerPeriod();
/**
* Return the maximum time in millisecond an {@link AsyncHttpClient} waits until the response is completed.
*
* @return the maximum time in millisecond an {@link AsyncHttpClient} waits until the response is completed.
*/
int getRequestTimeout();
/**
* Is HTTP redirect enabled
*
* @return true if enabled.
*/
boolean isFollowRedirect();
/**
* Get the maximum number of HTTP redirect
*
* @return the maximum number of HTTP redirect
*/
int getMaxRedirects();
/**
* Is the {@link ChannelPool} support enabled.
*
* @return true if keep-alive is enabled
*/
boolean isKeepAlive();
/**
* Return the USER_AGENT header value
*
* @return the USER_AGENT header value
*/
String getUserAgent();
/**
* Is HTTP compression enforced.
*
* @return true if compression is enforced
*/
boolean isCompressionEnforced();
/**
* Return the {@link java.util.concurrent.ThreadFactory} an {@link AsyncHttpClient} use for handling asynchronous response.
*
* @return the {@link java.util.concurrent.ThreadFactory} an {@link AsyncHttpClient} use for handling asynchronous response. If no {@link ThreadFactory} has been explicitly
* provided, this method will return <code>null</code>
*/
ThreadFactory getThreadFactory();
/**
* An instance of {@link ProxyServer} used by an {@link AsyncHttpClient}
*
* @return instance of {@link ProxyServer}
*/
ProxyServerSelector getProxyServerSelector();
/**
* Return an instance of {@link SslContext} used for SSL connection.
*
* @return an instance of {@link SslContext} used for SSL connection.
*/
SslContext getSslContext();
/**
* Return the current {@link Realm}
*
* @return the current {@link Realm}
*/
Realm getRealm();
/**
* Return the list of {@link RequestFilter}
*
* @return Unmodifiable list of {@link ResponseFilter}
*/
List<RequestFilter> getRequestFilters();
/**
* Return the list of {@link ResponseFilter}
*
* @return Unmodifiable list of {@link ResponseFilter}
*/
List<ResponseFilter> getResponseFilters();
/**
* Return the list of {@link java.io.IOException}
*
* @return Unmodifiable list of {@link java.io.IOException}
*/
List<IOExceptionFilter> getIoExceptionFilters();
/**
* Return cookie store that is used to store and retrieve cookies
*
* @return {@link CookieStore} object
*/
CookieStore getCookieStore();
/**
* Return the number of time the library will retry when an {@link java.io.IOException} is throw by the remote server
*
* @return the number of time the library will retry when an {@link java.io.IOException} is throw by the remote server
*/
int getMaxRequestRetry();
/**
* @return the disableUrlEncodingForBoundRequests
*/
boolean isDisableUrlEncodingForBoundRequests();
/**
* @return true if AHC is to use a LAX cookie encoder, eg accept illegal chars in cookie value
*/
boolean isUseLaxCookieEncoder();
/**
* In the case of a POST/Redirect/Get scenario where the server uses a 302 for the redirect, should AHC respond to the redirect with a GET or whatever the original method was.
* Unless configured otherwise, for a 302, AHC, will use a GET for this case.
*
* @return <code>true</code> if strict 302 handling is to be used, otherwise <code>false</code>.
*/
boolean isStrict302Handling();
/**
* @return the maximum time in millisecond an {@link AsyncHttpClient} will keep connection in the pool, or -1 to keep connection while possible.
*/
int getConnectionTtl();
boolean isUseOpenSsl();
boolean isUseInsecureTrustManager();
/**
* @return true to disable all HTTPS behaviors AT ONCE, such as hostname verification and SNI
*/
boolean isDisableHttpsEndpointIdentificationAlgorithm();
/**
* @return the array of enabled protocols
*/
String[] getEnabledProtocols();
/**
* @return the array of enabled cipher suites
*/
String[] getEnabledCipherSuites();
/**
* @return the size of the SSL session cache, 0 means using the default value
*/
int getSslSessionCacheSize();
/**
* @return the SSL session timeout in seconds, 0 means using the default value
*/
int getSslSessionTimeout();
//......
} AsyncHttpClientConfig接口定义了一系列获取配置的接口，比如getMaxConnections、getConnectTimeout、getReadTimeout、getPooledConnectionIdleTimeout等
DefaultAsyncHttpClientConfig
org/asynchttpclient/DefaultAsyncHttpClientConfig.java
代码语言：javascript复制public class DefaultAsyncHttpClientConfig implements AsyncHttpClientConfig {
//......
public static class Builder {
// timeouts
// keep-alive
// ssl
// cookie store
// tuning
// internals
}
}DefaultAsyncHttpClientConfig实现了AsyncHttpClientConfig接口，它还定义了一个Builder来用于创建AsyncHttpClient，其配置主要分为timeouts、keep-alive、ssl、cookie store、tuning、internals几个部分，它们的默认值读取的是jar包的ahc-default.properties的配置
timeouts
代码语言：javascript复制 // org.asynchttpclient.connectTimeout=5000
private int connectTimeout = defaultConnectTimeout();
// org.asynchttpclient.requestTimeout=60000
private int requestTimeout = defaultRequestTimeout();
// org.asynchttpclient.readTimeout=60000
private int readTimeout = defaultReadTimeout();
// org.asynchttpclient.shutdownQuietPeriod=2000
private int shutdownQuietPeriod = defaultShutdownQuietPeriod();
// org.asynchttpclient.shutdownTimeout=15000
private int shutdownTimeout = defaultShutdownTimeout();connectTimeout默认为5s、requestTimeout默认为60s、readTimeout默认为60s、shutdownQuietPeriod默认为2s、shutdownTimeout默认为15s
keep-alive
代码语言：javascript复制 // org.asynchttpclient.keepAlive=true
private boolean keepAlive = defaultKeepAlive();
// org.asynchttpclient.pooledConnectionIdleTimeout=60000
private int pooledConnectionIdleTimeout = defaultPooledConnectionIdleTimeout();
// org.asynchttpclient.connectionPoolCleanerPeriod=1000
private int connectionPoolCleanerPeriod = defaultConnectionPoolCleanerPeriod();
// org.asynchttpclient.connectionTtl=-1
private int connectionTtl = defaultConnectionTtl();
// org.asynchttpclient.maxConnections=-1
private int maxConnections = defaultMaxConnections();
// org.asynchttpclient.maxConnectionsPerHost=-1
private int maxConnectionsPerHost = defaultMaxConnectionsPerHost();
private ChannelPool channelPool;
private KeepAliveStrategy keepAliveStrategy = new DefaultKeepAliveStrategy();默认开启keepAlive、pooledConnectionIdleTimeout默认为60s、connectionPoolCleanerPeriod默认为1s、connectionTtl默认为-1、maxConnectionsPerHost默认为-1
tuning
代码语言：javascript复制 // org.asynchttpclient.tcpNoDelay=true
private boolean tcpNoDelay = defaultTcpNoDelay();
// org.asynchttpclient.soReuseAddress=false
private boolean soReuseAddress = defaultSoReuseAddress();
// org.asynchttpclient.soLinger=-1
private int soLinger = defaultSoLinger();
// org.asynchttpclient.soSndBuf=-1
private int soSndBuf = defaultSoSndBuf();
// org.asynchttpclient.soRcvBuf=-1
private int soRcvBuf = defaultSoRcvBuf();tcpNoDelay默认为true、soReuseAddress默认为false、soLinger、soSndBuf、soRcvBuf默认为-1
internals
代码语言：javascript复制 // org.asynchttpclient.threadPoolName=AsyncHttpClient
private String threadPoolName = defaultThreadPoolName();
// org.asynchttpclient.httpClientCodecMaxInitialLineLength=4096
private int httpClientCodecMaxInitialLineLength = defaultHttpClientCodecMaxInitialLineLength();
// org.asynchttpclient.httpClientCodecMaxHeaderSize=8192
private int httpClientCodecMaxHeaderSize = defaultHttpClientCodecMaxHeaderSize();
// org.asynchttpclient.httpClientCodecMaxChunkSize=8192
private int httpClientCodecMaxChunkSize = defaultHttpClientCodecMaxChunkSize();
// org.asynchttpclient.httpClientCodecInitialBufferSize=128
private int httpClientCodecInitialBufferSize = defaultHttpClientCodecInitialBufferSize();
// org.asynchttpclient.chunkedFileChunkSize=8192
private int chunkedFileChunkSize = defaultChunkedFileChunkSize();
// org.asynchttpclient.useNativeTransport=false
private boolean useNativeTransport = defaultUseNativeTransport();
private ByteBufAllocator allocator;
private Map<ChannelOption<Object>, Object> channelOptions = new HashMap<>();
private EventLoopGroup eventLoopGroup;
private Timer nettyTimer;
private ThreadFactory threadFactory;
private Consumer<Channel> httpAdditionalChannelInitializer;
private Consumer<Channel> wsAdditionalChannelInitializer;
private ResponseBodyPartFactory responseBodyPartFactory = ResponseBodyPartFactory.EAGER;
// org.asynchttpclient.ioThreadsCount=0
private int ioThreadsCount = defaultIoThreadsCount();threadPoolName默认为AsyncHttpClient、httpClientCodecMaxInitialLineLength默认为4096、httpClientCodecMaxHeaderSize默认为8192、httpClientCodecMaxChunkSize默认为8192、httpClientCodecInitialBufferSize默认为128、chunkedFileChunkSize默认为8192、ioThreadsCount默认为0
小结
DefaultAsyncHttpClientConfig实现了AsyncHttpClientConfig接口，它还定义了一个Builder来用于创建AsyncHttpClient，其配置主要分为timeouts、keep-alive、ssl、cookie store、tuning、internals几个部分，它们的默认值读取的是jar包的ahc-default.properties的配置。
