接着上一篇，我们在使用HttpClient的时候更多的是需要自己根据业务特点创建自己定制化的HttpClient实例，而不是像之前那样使用
// 使用默认配置创建httpclient的实例
CloseableHttpClient client = HttpClients.createDefault();
废话不多说，直接上代码(Talk is cheap, show me the code!)：
import org.apache.http.HttpEntity;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
/**
* 使用httpclient-4.5.2发送请求，配置请求定制化参数
* @author chmod400
* 2016.3.28
*/
public class RequestConfigDemo {
public static void main(String[] args) {
try {
String url = "http://www.baidu.com";
/**
* 请求参数配置
* connectionRequestTimeout:
* 从连接池中获取连接的超时时间，超过该时间未拿到可用连接，
* 会抛出org.apache.http.conn.ConnectionPoolTimeoutException: Timeout waiting for connection from pool
* connectTimeout:
* 连接上服务器(握手成功)的时间，超出该时间抛出connect timeout
* socketTimeout:
* 服务器返回数据(response)的时间，超过该时间抛出read timeout
*/
CloseableHttpClient client = HttpClients.custom().setDefaultRequestConfig(RequestConfig.custom()
.setConnectionRequestTimeout(2000).setConnectTimeout(2000).setSocketTimeout(2000).build()).build();
HttpPost post = new HttpPost(url);
// HttpGet get = new HttpGet(url);
CloseableHttpResponse response = client.execute(post);
// CloseableHttpResponse response = client.execute(get);
// 服务器返回码
int status_code = response.getStatusLine().getStatusCode();
System.out.println("status_code = " + status_code);
// 服务器返回内容
String respStr = null;
HttpEntity entity = response.getEntity();
if(entity != null) {
respStr = EntityUtils.toString(entity, "UTF-8");
}
System.out.println("respStr = " + respStr);
// 释放资源
EntityUtils.consume(entity);
} catch (Exception e) {
e.printStackTrace();
}
}
}
需要说明的是，需要自己定制HttpClient客户端的话，我们使用HttpClients.custom()，然后调用各种set方法即可，一般建议使用HttpClients.custom().setDefaultRequestConfig()，org.apache.http.client.config.RequestConfig类提供了很多可定制的参数，我们可以根据自己的配置来使用相关配置。有几个参数我们自己必须设置一下
connectionRequestTimeout:从连接池中获取连接的超时时间，超过该时间未拿到可用连接，会抛出org.apache.http.conn.ConnectionPoolTimeoutException: Timeout waiting for connection from pool
connectTimeout:连接上服务器(握手成功)的时间，超出该时间抛出connect timeout
socketTimeout:服务器返回数据(response)的时间，超过该时间抛出read timeout
通过打断点的方式我们知道，HttpClients在我们没有指定连接工厂的时候默认使用的是连接池工厂org.apache.http.impl.conn.PoolingHttpClientConnectionManager.PoolingHttpClientConnectionManager(Registry，所以我们需要配置一下从连接池获取连接池的超时时间。
以上3个超时相关的参数如果未配置，默认为-1，意味着无限大，就是一直阻塞等待！
官方提供了一个demo，里面有一些最常用的配置代码，仅供参考：
/*
* ====================================================================
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* responseParserFactory = new DefaultHttpResponseParserFactory() {
@Override
public HttpMessageParser create(
SessionInputBuffer buffer, MessageConstraints constraints) {
LineParser lineParser = new BasicLineParser() {
@Override
public Header parseHeader(final CharArrayBuffer buffer) {
try {
return super.parseHeader(buffer);
} catch (ParseException ex) {
return new BasicHeader(buffer.toString(), null);
}
}
};
return new DefaultHttpResponseParser(
buffer, lineParser, DefaultHttpResponseFactory.INSTANCE, constraints) {
@Override
protected boolean reject(final CharArrayBuffer line, int count) {
// try to ignore all garbage preceding a status line infinitely
return false;
}
};
}
};
HttpMessageWriterFactory requestWriterFactory = new DefaultHttpRequestWriterFactory();
// Use a custom connection factory to customize the process of
// initialization of outgoing HTTP connections. Beside standard connection
// configuration parameters HTTP connection factory can define message
// parser / writer routines to be employed by individual connections.
HttpConnectionFactory connFactory = new ManagedHttpClientConnectionFactory(
requestWriterFactory, responseParserFactory);
// Client HTTP connection objects when fully initialized can be bound to
// an arbitrary network socket. The process of network socket initialization,
// its connection to a remote address and binding to a local one is controlled
// by a connection socket factory.
// SSL context for secure connections can be created either based on
// system or application specific properties.
SSLContext sslcontext = SSLContexts.createSystemDefault();
// Create a registry of custom connection socket factories for supported
// protocol schemes.
Registry socketFactoryRegistry = RegistryBuilder.create()
.register("http", PlainConnectionSocketFactory.INSTANCE)
.register("https", new SSLConnectionSocketFactory(sslcontext))
.build();
// Use custom DNS resolver to override the system DNS resolution.
DnsResolver dnsResolver = new SystemDefaultDnsResolver() {
@Override
public InetAddress[] resolve(final String host) throws UnknownHostException {
if (host.equalsIgnoreCase("myhost")) {
return new InetAddress[] { InetAddress.getByAddress(new byte[] {127, 0, 0, 1}) };
} else {
return super.resolve(host);
}
}
};
// Create a connection manager with custom configuration.
PoolingHttpClientConnectionManager connManager = new PoolingHttpClientConnectionManager(
socketFactoryRegistry, connFactory, dnsResolver);
// Create socket configuration
SocketConfig socketConfig = SocketConfig.custom()
.setTcpNoDelay(true)
.build();
// Configure the connection manager to use socket configuration either
// by default or for a specific host.
connManager.setDefaultSocketConfig(socketConfig);
connManager.setSocketConfig(new HttpHost("somehost", 80), socketConfig);
// Validate connections after 1 sec of inactivity
connManager.setValidateAfterInactivity(1000);
// Create message constraints
MessageConstraints messageConstraints = MessageConstraints.custom()
.setMaxHeaderCount(200)
.setMaxLineLength(2000)
.build();
// Create connection configuration
ConnectionConfig connectionConfig = ConnectionConfig.custom()
.setMalformedInputAction(CodingErrorAction.IGNORE)
.setUnmappableInputAction(CodingErrorAction.IGNORE)
.setCharset(Consts.UTF_8)
.setMessageConstraints(messageConstraints)
.build();
// Configure the connection manager to use connection configuration either
// by default or for a specific host.
connManager.setDefaultConnectionConfig(connectionConfig);
connManager.setConnectionConfig(new HttpHost("somehost", 80), ConnectionConfig.DEFAULT);
// Configure total max or per route limits for persistent connections
// that can be kept in the pool or leased by the connection manager.
connManager.setMaxTotal(100);
connManager.setDefaultMaxPerRoute(10);
connManager.setMaxPerRoute(new HttpRoute(new HttpHost("somehost", 80)), 20);
// Use custom cookie store if necessary.
CookieStore cookieStore = new BasicCookieStore();
// Use custom credentials provider if necessary.
CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
// Create global request configuration
RequestConfig defaultRequestConfig = RequestConfig.custom()
.setCookieSpec(CookieSpecs.DEFAULT)
.setExpectContinueEnabled(true)
.setTargetPreferredAuthSchemes(Arrays.asList(AuthSchemes.NTLM, AuthSchemes.DIGEST))
.setProxyPreferredAuthSchemes(Arrays.asList(AuthSchemes.BASIC))
.build();
// Create an HttpClient with the given custom dependencies and configuration.
CloseableHttpClient httpclient = HttpClients.custom()
.setConnectionManager(connManager)
.setDefaultCookieStore(cookieStore)
.setDefaultCredentialsProvider(credentialsProvider)
.setProxy(new HttpHost("myproxy", 8080))
.setDefaultRequestConfig(defaultRequestConfig)
.build();
try {
HttpGet httpget = new HttpGet("http://httpbin.org/get");
// Request configuration can be overridden at the request level.
// They will take precedence over the one set at the client level.
RequestConfig requestConfig = RequestConfig.copy(defaultRequestConfig)
.setSocketTimeout(5000)
.setConnectTimeout(5000)
.setConnectionRequestTimeout(5000)
.setProxy(new HttpHost("myotherproxy", 8080))
.build();
httpget.setConfig(requestConfig);
// Execution context can be customized locally.
HttpClientContext context = HttpClientContext.create();
// Contextual attributes set the local context level will take
// precedence over those set at the client level.
context.setCookieStore(cookieStore);
context.setCredentialsProvider(credentialsProvider);
System.out.println("executing request " + httpget.getURI());
CloseableHttpResponse response = httpclient.execute(httpget, context);
try {
System.out.println("----------------------------------------");
System.out.println(response.getStatusLine());
System.out.println(EntityUtils.toString(response.getEntity()));
System.out.println("----------------------------------------");
// Once the request has been executed the local context can
// be used to examine updated state and various objects affected
// by the request execution.
// Last executed request
context.getRequest();
// Execution route
context.getHttpRoute();
// Target auth state
context.getTargetAuthState();
// Proxy auth state
context.getTargetAuthState();
// Cookie origin
context.getCookieOrigin();
// Cookie spec used
context.getCookieSpec();
// User security token
context.getUserToken();
} finally {
response.close();
}
} finally {
httpclient.close();
}
}
}