使用httpclient4.4发送请求

对httpclient4.4进行封装

1.httpclient单例模式

2.请求异常重试三次

3.支持get和post

4.Constant.REQUEST_TIMEOUT等为数字常量，可以自行指定

import java.io.IOException;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
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.HttpUriRequest;
import org.apache.http.entity.BufferedHttpEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.apache.http.util.EntityUtils;

public class HttpEngine {
private CloseableHttpClient httpClient = null;
/ 单例模式声明开始 /
// 类初始化时，自行实例化，饿汉式单例模式
private static final HttpEngine httpEngine = new HttpEngine();

public static HttpEngine getHttpEngineInstance() {
return httpEngine;
}

private HttpEngine() {
initHttpClient();
}

private void initHttpClient() {
// 创建httpclient连接池
PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager();
cm.setMaxTotal(200); // 设置连接池线程最大数量
cm.setDefaultMaxPerRoute(100); // 设置单个路由最大的连接线程数量
// 创建http request的配置信息
RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(Constant.REQUEST_TIMEOUT)
.setConnectTimeout(Constant.REQUEST_TIMEOUT).setSocketTimeout(Constant.REQUEST_SOCKET_TIME).build();
// 设置重定向策略
// LaxRedirectStrategy redirectStrategy = new LaxRedirectStrategy();
// 初始化httpclient客户端
httpClient = HttpClients.custom().setConnectionManager(cm).setDefaultRequestConfig(requestConfig).build();
}

public String execute(String url) {
String result = "";
if (null == url || "".equals(url)) {
result = "";
// 如果url为空或者null，则返回src空值ֵ
} else {
// 创建httpclient请求方式
HttpGet httpGet = new HttpGet(url);
CloseableHttpResponse response = null;
try {
response = makeRequestWithRetries(httpGet);
result = parseResponse2String(response);
} catch (IOException e) {
// log
} finally {
if (null != response) {
try {
// 关闭response
response.close();
httpGet.abort();
} catch (IOException e) {
// TODO 这里写异常处理的代码
e.printStackTrace();
}
}
}
}
return result;
}

public CloseableHttpResponse execute(HttpUriRequest request) throws IOException {
CloseableHttpResponse response = null;
if (null == request) {
response = null;
// 如果httpPost为空或者null，则返回空
} else {
// 创建httpclient请求方式
response = makeRequestWithRetries(request);
}
return response;
}

//抛异常重试三次
private CloseableHttpResponse makeRequestWithRetries(HttpUriRequest request) {
CloseableHttpResponse response = null;
int retryCount = 0;
while (retryCount++ < Constant.HTTP_MAX_RETRIES) {
try {
return response = httpClient.execute(request);
} catch (ClientProtocolException e) {
System.out.println("RETRIES again " + retryCount + " in makeRequestWithRetries<request>: "
<ul>
 	<li>e.getMessage());
e.printStackTrace();</li>
</ul>
} catch (IOException e) {
System.out.println("RETRIES again " + retryCount + " in makeRequestWithRetries&lt;request&gt;: "
<ul>
 	<li>e.getMessage());
e.printStackTrace();</li>
</ul>
}
}
return response;
}

public static String parseResponse2String(HttpResponse response) throws IOException {

String responseBody = "";

HttpEntity entity = null;
HttpEntity temp = response.getEntity();
if (temp != null) {
entity = new BufferedHttpEntity(temp);
responseBody = EntityUtils.toString(entity);
}

return responseBody;

}

// public static void main(String args[]) throws IOException, ParseException
// {
// // 使用方式1
// HttpEngine httpEngine = HttpEngine.getHttpEngineInstance();
// String result =
// httpEngine.execute("<a href="http://www.baidu.com/?param1=sfdsfsdfs&amp;">http://www.baidu.com?param1=sfdsfsdfs&amp;</a>;param2=9897979789789");
// System.out.println(result);
//
// // 使用方法2
// List&lt;NameValuePair&gt; formparams = new ArrayList&lt;NameValuePair&gt;();
// formparams.add(new BasicNameValuePair("param1", "sfdsfsdfs"));
// formparams.add(new BasicNameValuePair("param2", "9897979789789"));
// UrlEncodedFormEntity entity = new UrlEncodedFormEntity(formparams,
// Consts.UTF_8);
// HttpPost httpPost = new HttpPost("www.baidu.com");
// httpPost.setEntity(entity);
// CloseableHttpResponse response = httpEngine.execute(httpPost);
// result = parseResponse2String(response);
// response.close();
// System.out.println(result);

// }

}