HttpComponents組件特性探究

　　在Java領域，談到網絡編程，可能大家腦海里第一反應就是MINA，NETTY，GRIZZLY等優秀的開源框架。沒錯，不過在深入探究這些框架之前，我們需要先從最original的技術探究開始(當然，需要大家先熟悉java.net.*類庫)。這里，我要和大家分享一下HttpComponents項目的部分組件特性。HttpClient，想必大家早都接觸過了吧。HttpComponents和HttpClient的”血緣“有點像guava和google-collection的關系。目前，HttpComponents已經是Apache的頂級項目了，它旨在為我們提供一個Http協議相關的Java平臺工具集。它的代碼組織很精妙，主要分兩部分，一部分是核心工具集(包括HttpCore-bio,HttpCore-nio，HttpClient，HttpMIme，HttpCookie等)，一部分是擴展工具集(目前主要包括ssl)

　　HttpClient主要包括Connection management，Status management，Authentication Management三部分。下面給出對它的二次封裝，經過了線上的接近半年的驗證(這里指的是httpClient 3,httpClient 4還有待檢驗)，可以看做是一個高性能的Client封裝吧。感興趣的朋友可以根據apache的MPM IO模型進行部分參數的調整。

　　先來段httpClient 4的封裝,代碼如下:

　　[java] view plaincopyprint?

　　/**

　　* @author von gosling 2012-3-2

　　*/

　　public class HttpComponentsClientExecutor implements DisposableBean {

　　private static final int DEFAULT_MAX_TOTAL_CONNECTIONS = 100;

　　private static final int DEFAULT_MAX_CONNECTIONS_PER_ROUTE = 5; //notice IE 6,7,8

　　private static final int DEFAULT_CONN_TIMEOUT_MILLISECONDS = 5 * 1000;

　　private static final int DEFAULT_READ_TIMEOUT_MILLISECONDS = 60 * 1000;

　　private static final String HTTP_HEADER_CONTENT_ENCODING = "Content-Encoding";

　　private static final String ENCODING_GZIP = "gzip";

　　private HttpClient httpClient;

　　/**

　　* Create a new instance of the HttpComponentsClient with a default

　　* {@link HttpClient} that uses a default

　　* {@link org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager}.

　　*/

　　public HttpComponentsClientExecutor() {

　　SchemeRegistry schemeRegistry = new SchemeRegistry();

　　schemeRegistry.register(new Scheme("http", 80, PlainSocketFactory.getSocketFactory()));

　　schemeRegistry.register(new Scheme("https", 443, SSLSocketFactory.getSocketFactory()));

　　ThreadSafeClientConnManager connectionManager = new ThreadSafeClientConnManager(

　　schemeRegistry);

　　connectionManager.setMaxTotal(DEFAULT_MAX_TOTAL_CONNECTIONS);

　　connectionManager.setDefaultMaxPerRoute(DEFAULT_MAX_CONNECTIONS_PER_ROUTE);

　　this.httpClient = new DefaultHttpClient(connectionManager);

　　setConnectTimeout(DEFAULT_CONN_TIMEOUT_MILLISECONDS);

　　setReadTimeout(DEFAULT_READ_TIMEOUT_MILLISECONDS);

　　}

　　/**

　　* Create a new instance of the HttpComponentsClient with the given

　　* {@link HttpClient} instance.

　　*

　　* @param httpClient the HttpClient instance to use for this request

　　*/

　　public HttpComponentsClientExecutor(HttpClient httpClient) {

　　Validate.notNull(httpClient, "HttpClient must not be null");

　　//notice: if you want to custom exception recovery mechanism

　　//you should provide an implementation of the HttpRequestRetryHandler interface.

　　this.httpClient = httpClient;

　　}

　　/**

　　* Set the {@code HttpClient} used by this request.

　　*/

　　public void setHttpClient(HttpClient httpClient) {

　　this.httpClient = httpClient;

　　}

　　/**

　　* Return the {@code HttpClient} used by this request.

　　*/

　　public HttpClient getHttpClient() {

　　return this.httpClient;

　　}

　　/**

　　* Set the connection timeout for the underlying HttpClient. A timeout value

　　* of 0 specifies an infinite timeout.

　　*

　　* @param timeout the timeout value in milliseconds

　　*/

　　public void setConnectTimeout(int timeout) {

　　Validate.isTrue(timeout >= 0, "Timeout must be a non-negative value");

　　getHttpClient().getParams().setIntParameter(CoreConnectionPNames.CONNECTION_TIMEOUT,

　　timeout);

　　}

　　/**

　　* Set the socket timeout (SO_TIMEOUT) in milliseconds, which is the timeout

　　* for waiting for data or, put differently, a maximum period inactivity

　　* between two consecutive data packets.A timeout value of 0 specifies an

　　* infinite timeout.

　　*

　　* @param timeout the timeout value in milliseconds

　　*/

　　public void setReadTimeout(int timeout) {

　　Validate.isTrue(timeout >= 0, "Timeout must be a non-negative value");

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