httpclient工具类,使用连接池实现，原理同数据库连接池。

使用httpclient4.5实现。

注意事项:

1.user-agent最好不要乱写，百度一些放到文件，每次请求随机读取最好。

2.最好设置请求停顿时间，防止访问过快被封。

3.返回结果乱码请设置返回的数据的编码格式,默认utf8.

代码:

package com.common.util;

import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.URI;
import java.net.URL;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.TimeUnit;

import javax.net.ssl.SSLException;

import org.apache.http.HttpEntityEnclosingRequest;
import org.apache.http.HttpHost;
import org.apache.http.HttpRequest;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.HttpRequestRetryHandler;
import org.apache.http.client.ResponseHandler;
import org.apache.http.client.config.CookieSpecs;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.entity.UrlEncodedFormEntity;
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.client.protocol.HttpClientContext;
import org.apache.http.config.Registry;
import org.apache.http.config.RegistryBuilder;
import org.apache.http.conn.ConnectTimeoutException;
import org.apache.http.conn.socket.ConnectionSocketFactory;
import org.apache.http.conn.socket.PlainConnectionSocketFactory;
import org.apache.http.conn.ssl.NoopHostnameVerifier;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.conn.ssl.TrustSelfSignedStrategy;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.impl.client.LaxRedirectStrategy;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.apache.http.message.AbstractHttpMessage;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.protocol.HttpContext;
import org.apache.http.ssl.SSLContextBuilder;
import org.apache.http.util.EntityUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@SuppressWarnings("all")
public class HttpUtil {
private static final Logger LOGGER = LoggerFactory.getLogger(HttpUtil.class);
public static final long RELEASE_CONNECTION_WAIT_TIME = 5000;// 监控连接间隔
private static PoolingHttpClientConnectionManager httpClientConnectionManager = null;
private static LaxRedirectStrategy redirectStrategy = null;
private static HttpRequestRetryHandler myRetryHandler = null;
private static SSLConnectionSocketFactory sslConnectionSocketFactory = null;
private static MyResponseHandler rh = null;

static {
initHttpClient();
// 启动清理连接池链接线程
Thread idleConnectionMonitorThread = new IdleConnectionMonitorThread(httpClientConnectionManager);
idleConnectionMonitorThread.setDaemon(true);
idleConnectionMonitorThread.start();
}

public static void initHttpClient() {
try {
rh = new MyResponseHandler();
// 重定向策略初始化
redirectStrategy = new LaxRedirectStrategy();
// 请求重试机制，默认重试3次
myRetryHandler = new HttpRequestRetryHandler() {
public boolean retryRequest(IOException exception, int executionCount, HttpContext context) {
if (executionCount >= 3) {
return false;
}
if (exception instanceof InterruptedIOException) {
return false;
}
if (exception instanceof UnknownHostException) {
return false;
}
if (exception instanceof ConnectTimeoutException) {
return false;
}
if (exception instanceof SSLException) {
// SSL handshake exception
return false;
}
HttpClientContext clientContext = HttpClientContext.adapt(context);
HttpRequest request = clientContext.getRequest();
boolean idempotent = !(request instanceof HttpEntityEnclosingRequest);
if (idempotent) {
// Retry if the request is considered idempotent
return true;
}
return false;
}
};
SSLContextBuilder builder = new SSLContextBuilder();
builder.loadTrustMaterial(null, new TrustSelfSignedStrategy());
sslConnectionSocketFactory = new SSLConnectionSocketFactory(builder.build(), NoopHostnameVerifier.INSTANCE);
Registry<ConnectionSocketFactory> registry = RegistryBuilder.<ConnectionSocketFactory>create()
.register("http", new PlainConnectionSocketFactory())//
.register("https", sslConnectionSocketFactory)//
.build();
// 创建httpclient连接池
httpClientConnectionManager = new PoolingHttpClientConnectionManager(registry);
// 设置连接池最大数量,这个参数表示所有连接最大数。
httpClientConnectionManager.setMaxTotal(200);
// 设置
d858
单个路由最大连接数量，表示单个域名的最大连接数，
// 例如:www.baidu.com.www.google.com表示不同的域名,则连接统一域名下的资源的最大连接数就是该参数,总和是上面的参数。
httpClientConnectionManager.setDefaultMaxPerRoute(100);
} catch (Exception e) {
LOGGER.error("初始化httpclient连接池失败.", e);
}

}

public static CloseableHttpClient getHttpClient() {
// HttpHost ip = ConfigFileUtil.getRandomIp();
RequestConfig requestConfig = RequestConfig.custom()//
.setConnectTimeout(3000)//
.setSocketTimeout(3000)//
// 忽略cookie,如果不需要登陆最好去掉,否则修改策略保存cookie即可
.setCookieSpec(CookieSpecs.IGNORE_COOKIES)//
.setConnectionRequestTimeout(6000)//
// .setProxy(ip)//设置代理ip,不设置就用本机
.build();
// 连接池配置
CloseableHttpClient httpClient = HttpClients.custom()//
.setSSLSocketFactory(sslConnectionSocketFactory)//
.setConnectionManager(httpClientConnectionManager)//
.setDefaultRequestConfig(requestConfig)//
.setRedirectStrategy(redirectStrategy)//
.setRetryHandler(myRetryHandler)//
.build();

return httpClient;
}

/**
* get请求 headers表示特殊的请求头
*/
public static String getUrlContent(String urlString, Map<String, String>... headers) {
String html = "";
HttpGet httpGet = null;
urlString = urlString.trim();
if (null == urlString || urlString.isEmpty() || !urlString.startsWith("http")) {
return html;
}
// 转化String url为URI,解决url中包含特殊字符的情况
try {
URL url = new URL(urlString);
URI uri = new URI(url.getProtocol(), url.getHost(), url.getPath(), url.getQuery(), null);
httpGet = new HttpGet(uri);
setCommonHeaders(httpGet);
// 额外的header
if (headers != null && headers.length > 0) {
for (Map.Entry<String, String> header : headers[0].entrySet()) {
if (httpGet.containsHeader(header.getKey())) {
httpGet.setHeader(header.getKey(), header.getValue());
} else {
httpGet.addHeader(header.getKey(), header.getValue());
}
}
}
HttpClient httpClient = getHttpClient();
html = httpClient.execute(httpGet, rh);
} catch (Exception e) {
LOGGER.error("请求错误·url=" + urlString);
} finally {
httpGet.abort();
}
return html;
}

/**
* post请求,params表示参数,headers表示请求头
*/
public static String postForEntity(String urlString, Map<String, String> params, Map<String, String>... headers) {
String html = "";
HttpPost httpPost = null;
urlString = urlString.trim();
try {
// 参数设置
if (null == urlString || urlString.isEmpty() || !urlString.startsWith("http")) {
return html;
}
URL url = new URL(urlString);
URI uri = new URI(url.getProtocol(), url.getHost(), url.getPath(), url.getQuery(), null);
httpPost = new HttpPost(uri);
setCommonHeaders(httpPost);
// 额外的header
if (headers != null && headers.length > 0) {
for (Map.Entry<String, String> header : headers[0].entrySet()) {
if (httpPost.containsHeader(header.getKey())) {
httpPost.setHeader(header.getKey(), header.getValue());
} else {
httpPost.addHeader(header.getKey(), header.getValue());
}
}
}
if (params != null && params.size() > 0) {
List<BasicNameValuePair> nvps = new ArrayList<>();
for (Map.Entry<String, String> entry : params.entrySet()) {
nvps.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
}
// 这里设置的是返回结果编码,大多数都是UTF-8,如果乱码,可以查看网页的meta中的content的编码.如果是GBK,这里改为GBK即可.
// 这里entity只能读取一次,想要读取多次,百度一下.
httpPost.setEntity(new UrlEncodedFormEntity(nvps, "UTF-8"));
}
HttpClient httpClient = getHttpClient();
html = httpClient.execute(httpPost, rh);
} catch (Exception e) {
LOGGER.error("请求错误·url=" + urlString);
} finally {
httpPost.abort();
}
return html;

}

private static void setCommonHeaders(AbstractHttpMessage request) {
request.addHeader("Accept",
"text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8");
// request.addHeader("Connection", "keep-alive");
request.addHeader("Accept-Language", "zh-CN,zh;q=0.8");
request.addHeader("Accept-Encoding", "gzip, deflate, br");
// User-Agent最好随机换
request.addHeader("User-Agent",
"Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.94 Safari/537.36");
}

/**
* 响应处理类,处理返回结果
*
* @author 王
*
*/
public static class MyResponseHandler implements ResponseHandler<String> {

@Override
public String handleResponse(HttpResponse response) throws ClientProtocolException, IOException {
try {
// 返回状态码
int statusCode = response.getStatusLine().getStatusCode();
switch (statusCode) {
case 200:
return EntityUtils.toString(response.getEntity(), "UTF-8");
case 400:
LOGGER.error("下载400错误代码，请求出现语法错误.");
break;
case 403:
LOGGER.error("下载403错误代码，资源不可用.");
break;
case 404:
LOGGER.error("下载404错误代码，无法找到指定资源地址.");
break;
case 503:
LOGGER.error("下载503错误代码，服务不可用.");
break;
case 504:
LOGGER.error("下载504错误代码，网关超时.");
break;
default:
LOGGER.error("未处理的错误,code=" + statusCode);
}

} finally {
if (response != null) {
try {
((CloseableHttpResponse) response).close();
} catch (IOException e) {
LOGGER.error("关闭响应错误.", e);
}
}
}
return "";
}

}

/**
* 连接处理,释放连接池连接
*
* @author 王
*
*/
public static class IdleConnectionMonitorThread extends Thread {

private static volatile boolean shutdown = false;
private PoolingHttpClientConnectionManager poolingHttpClientConnectionManager;

public IdleConnectionMonitorThread(PoolingHttpClientConnectionManager poolingHttpClientConnectionManager) {
this.poolingHttpClientConnectionManager = poolingHttpClientConnectionManager;
}

@Override
public void run() {
try {
while (!shutdown) {
synchronized (IdleConnectionMonitorThread.class) {
wait(RELEASE_CONNECTION_WAIT_TIME);
// Close expired connections
poolingHttpClientConnectionManager.closeExpiredConnections();
// that have been idle longer than 30 sec
poolingHttpClientConnectionManager.closeIdleConnections(2, TimeUnit.MINUTES);
}
}
} catch (InterruptedException ex) {
LOGGER.error("释放连接池连接出错.");
}
}

public void shutdown() {
shutdown = true;
synchronized (IdleConnectionMonitorThread.class) {
notifyAll();
}
}

}

public static boolean checkIp(HttpHost ip) {
HttpResponse response;
int code = 0;
try {
String url = "https://www.baidu.com";
HttpClient hc = HttpClients.custom()//
.setProxy(ip)//
.build();
HttpGet httpGet = new HttpGet(url);
response = hc.execute(httpGet);
code = response.getStatusLine().getStatusCode();
} catch (Exception e) {
e.printStackTrace();
}
return code == 200;
}

public static void main(String[] args) {
System.out.println(getUrlContent("https://www.baidu.com"));
}

}