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")); } }