java HttpClicent网络请求与解析
HttpClicent是Apache下的一个子项目，文档齐全，详见官网：http://hc.apache.org/httpcomponents-client-4.5.x/quickstart.html
这里列出一些常见用法：
（1）使用步骤：
1. 创建HttpClient对象。
2. 创建请求方法的实例，并指定请求URL。如果需要发送GET请求，创建HttpGet对象；如果需要发送POST请求，创建HttpPost对象。
3. 如果需要发送请求参数，可调用HttpGet、HttpPost共同的setParams(HetpParams params)方法来添加请求参数；对于HttpPost对象而言，也可调用setEntity(HttpEntity entity)方法来设置请求参数。
4. 调用HttpClient对象的execute(HttpUriRequest request)发送请求，该方法返回一个HttpResponse。
5. 调用HttpResponse的getAllHeaders()、getHeaders(String name)等方法可获取服务器的响应头；调用HttpResponse的getEntity()方法可获取HttpEntity对象，该对象包装了服务器的响应内容。程序可通过该对象获取服务器的响应内容。
6. 释放连接。无论执行方法是否成功，都必须释放连接
（2）官网示例：CloseableHttpClient httpclient = HttpClients.createDefault();HttpGet httpGet = new HttpGet("http://targethost/homepage");
CloseableHttpResponse response1 = httpclient.execute(httpGet); // The underlying HTTP connection is still held by the response object // to allow the response content to be streamed directly from the network socket. // In order to ensure correct deallocation of system resources // the user MUST call CloseableHttpResponse#close() from a finally clause. // Please note that if response content is not fully consumed the underlying // connection cannot be safely re-used and will be shut down and discarded // by the connection manager. try { System.out.println(response1.getStatusLine()); HttpEntity entity1 = response1.getEntity(); // do something useful with the response body // and ensure it is fully consumed EntityUtils.consume(entity1); } finally { response1.close(); } HttpPost httpPost = new HttpPost("http://targethost/login"); List <NameValuePair> nvps = new ArrayList <NameValuePair>(); nvps.add(new BasicNameValuePair("username", "vip")); nvps.add(new BasicNameValuePair("password", "secret")); httpPost.setEntity(new UrlEncodedFormEntity(nvps)); CloseableHttpResponse response2 = httpclient.execute(httpPost); try { System.out.println(response2.getStatusLine()); HttpEntity entity2 = response2.getEntity(); // do something useful with the response body // and ensure it is fully consumed EntityUtils.consume(entity2); } finally { response2.close(); }
（3）解析结果：
1.返回时JSON:
List<NameValuePair> nvps = new ArrayList<NameValuePair>(); nvps.add(new BasicNameValuePair("loginname","ss")); nvps.add(new BasicNameValuePair("password", "s123")); hp.setEntity(new UrlEncodedFormEntity(nvps)); HttpResponse res = client.execute(hp); html = EntityUtils.toString(res.getEntity());
JSONObject obj = JSON.parseObject(html);//这里用了fastjson，把String类型的html转换成JSON对象，若有多个，可转换成数组
Iterator it = obj.keySet().iterator();
while(it.hasNext()){
String key = it.next().toString();
if(key.equals("Success")){
html = obj.get(key).toString();
}
}
2.返回html:
HttpGet hg = new HttpGet(course_list_url); HttpResponse res = client.execute(hg); html = EntityUtils.toString(res.getEntity()); Document doc = Jsoup.parse(html);//这里用了Jsoup抓取需要的html代码 Element content = doc.getElementById("col-sm-5"); Elements links = content.getElementsByTag("a"); for (Element link : links) { String linkHref = link.attr("href"); String linkText = link.text(); } String courseId = ""; Elements courseIds = doc.select("div.overflow-h>a[href]"); Elements courseTimes = doc.select("h3.heading-xs>a");
（4）其他关于HttoClicent相关例子：
1 package com.test; 2 3 import java.io.File; 4 import java.io.FileInputStream; 5 import java.io.IOException; 6 import java.io.UnsupportedEncodingException; 7 import java.security.KeyManagementException; 8 import java.security.KeyStore; 9 import java.security.KeyStoreException; 10 import java.security.NoSuchAlgorithmException; 11 import java.security.cert.CertificateException; 12 import java.util.ArrayList; 13 import java.util.List; 14 15 import javax.net.ssl.SSLContext; 16 17 import org.apache.http.HttpEntity; 18 import org.apache.http.NameValuePair; 19 import org.apache.http.ParseException; 20 import org.apache.http.client.ClientProtocolException; 21 import org.apache.http.client.entity.UrlEncodedFormEntity; 22 import org.apache.http.client.methods.CloseableHttpResponse; 23 import org.apache.http.client.methods.HttpGet; 24 import org.apache.http.client.methods.HttpPost; 25 import org.apache.http.conn.ssl.SSLConnectionSocketFactory; 26 import org.apache.http.conn.ssl.SSLContexts; 27 import org.apache.http.conn.ssl.TrustSelfSignedStrategy; 28 import org.apache.http.entity.ContentType; 29 import org.apache.http.entity.mime.MultipartEntityBuilder; 30 import org.apache.http.entity.mime.content.FileBody; 31 import org.apache.http.entity.mime.content.StringBody; 32 import org.apache.http.impl.client.CloseableHttpClient; 33 import org.apache.http.impl.client.HttpClients; 34 import org.apache.http.message.BasicNameValuePair; 35 import org.apache.http.util.EntityUtils; 36 import org.junit.Test; 37 38 public class HttpClientTest { 39 40 @Test 41 public void jUnitTest() { 42 get(); 43 } 44 45 /** 46 * HttpClient连接SSL 47 */ 48 public void ssl() { 49 CloseableHttpClient httpclient = null; 50 try { 51 KeyStore trustStore = KeyStore.getInstance(KeyStore.getDefaultType()); 52 FileInputStream instream = new FileInputStream(new File("d:\\tomcat.keystore")); 53 try { 54 // 加载keyStore d:\\tomcat.keystore 55 trustStore.load(instream, "123456".toCharArray()); 56 } catch (CertificateException e) { 57 e.printStackTrace(); 58 } finally { 59 try { 60 instream.close(); 61 } catch (Exception ignore) { 62 } 63 } 64 // 相信自己的CA和所有自签名的证书 65 SSLContext sslcontext = SSLContexts.custom().loadTrustMaterial(trustStore, new TrustSelfSignedStrategy()).build(); 66 // 只允许使用TLSv1协议 67 SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslcontext, new String[] { "TLSv1" }, null, 68 SSLConnectionSocketFactory.BROWSER_COMPATIBLE_HOSTNAME_VERIFIER); 69 httpclient = HttpClients.custom().setSSLSocketFactory(sslsf).build(); 70 // 创建http请求(get方式) 71 HttpGet httpget = new HttpGet("https://localhost:8443/myDemo/Ajax/serivceJ.action"); 72 System.out.println("executing request" + httpget.getRequestLine()); 73 CloseableHttpResponse response = httpclient.execute(httpget); 74 try { 75 HttpEntity entity = response.getEntity(); 76 System.out.println("----------------------------------------"); 77 System.out.println(response.getStatusLine()); 78 if (entity != null) { 79 System.out.println("Response content length: " + entity.getContentLength()); 80 System.out.println(EntityUtils.toString(entity)); 81 EntityUtils.consume(entity); 82 } 83 } finally { 84 response.close(); 85 } 86 } catch (ParseException e) { 87 e.printStackTrace(); 88 } catch (IOException e) { 89 e.printStackTrace(); 90 } catch (KeyManagementException e) { 91 e.printStackTrace(); 92 } catch (NoSuchAlgorithmException e) { 93 e.printStackTrace(); 94 } catch (KeyStoreException e) { 95 e.printStackTrace(); 96 } finally { 97 if (httpclient != null) { 98 try { 99 httpclient.close(); 100 } catch (IOException e) { 101 e.printStackTrace(); 102 } 103 } 104 } 105 } 106 107 /** 108 * post方式提交表单（模拟用户登录请求） 109 */ 110 public void postForm() { 111 // 创建默认的httpClient实例. 112 CloseableHttpClient httpclient = HttpClients.createDefault(); 113 // 创建httppost 114 HttpPost httppost = new HttpPost("http://localhost:8080/myDemo/Ajax/serivceJ.action"); 115 // 创建参数队列 116 List<namevaluepair> formparams = new ArrayList<namevaluepair>(); 117 formparams.add(new BasicNameValuePair("username", "admin")); 118 formparams.add(new BasicNameValuePair("password", "123456")); 119 UrlEncodedFormEntity uefEntity; 120 try { 121 uefEntity = new UrlEncodedFormEntity(formparams, "UTF-8"); 122 httppost.setEntity(uefEntity); 123 System.out.println("executing request " + httppost.getURI()); 124 CloseableHttpResponse response = httpclient.execute(httppost); 125 try { 126 HttpEntity entity = response.getEntity(); 127 if (entity != null) { 128 System.out.println("--------------------------------------"); 129 System.out.println("Response content: " + EntityUtils.toString(entity, "UTF-8")); 130 System.out.println("--------------------------------------"); 131 } 132 } finally { 133 response.close(); 134 } 135 } catch (ClientProtocolException e) { 136 e.printStackTrace(); 137 } catch (UnsupportedEncodingException e1) { 138 e1.printStackTrace(); 139 } catch (IOException e) { 140 e.printStackTrace(); 141 } finally { 142 // 关闭连接,释放资源 143 try { 144 httpclient.close(); 145 } catch (IOException e) { 146 e.printStackTrace(); 147 } 148 } 149 } 150 151 /** 152 * 发送 post请求访问本地应用并根据传递参数不同返回不同结果 153 */ 154 public void post() { 155 // 创建默认的httpClient实例. 156 CloseableHttpClient httpclient = HttpClients.createDefault(); 157 // 创建httppost 158 HttpPost httppost = new HttpPost("http://localhost:8080/myDemo/Ajax/serivceJ.action"); 159 // 创建参数队列 160 List<namevaluepair> formparams = new ArrayList<namevaluepair>(); 161 formparams.add(new BasicNameValuePair("type", "house")); 162 UrlEncodedFormEntity uefEntity; 163 try { 164 uefEntity = new UrlEncodedFormEntity(formparams, "UTF-8"); 165 httppost.setEntity(uefEntity); 166 System.out.println("executing request " + httppost.getURI()); 167 CloseableHttpResponse response = httpclient.execute(httppost); 168 try { 169 HttpEntity entity = response.getEntity(); 170 if (entity != null) { 171 System.out.println("--------------------------------------"); 172 System.out.println("Response content: " + EntityUtils.toString(entity, "UTF-8")); 173 System.out.println("--------------------------------------"); 174 } 175 } finally { 176 response.close(); 177 } 178 } catch (ClientProtocolException e) { 179 e.printStackTrace(); 180 } catch (UnsupportedEncodingException e1) { 181 e1.printStackTrace(); 182 } catch (IOException e) { 183 e.printStackTrace(); 184 } finally { 185 // 关闭连接,释放资源 186 try { 187 httpclient.close(); 188 } catch (IOException e) { 189 e.printStackTrace(); 190 } 191 } 192 } 193 194 /** 195 * 发送 get请求 196 */ 197 public void get() { 198 CloseableHttpClient httpclient = HttpClients.createDefault(); 199 try { 200 // 创建httpget. 201 HttpGet httpget = new HttpGet("http://www.baidu.com/"); 202 System.out.println("executing request " + httpget.getURI()); 203 // 执行get请求. 204 CloseableHttpResponse response = httpclient.execute(httpget); 205 try { 206 // 获取响应实体 207 HttpEntity entity = response.getEntity(); 208 System.out.println("--------------------------------------"); 209 // 打印响应状态 210 System.out.println(response.getStatusLine()); 211 if (entity != null) { 212 // 打印响应内容长度 213 System.out.println("Response content length: " + entity.getContentLength()); 214 // 打印响应内容 215 System.out.println("Response content: " + EntityUtils.toString(entity)); 216 } 217 System.out.println("------------------------------------"); 218 } finally { 219 response.close(); 220 } 221 } catch (ClientProtocolException e) { 222 e.printStackTrace(); 223 } catch (ParseException e) { 224 e.printStackTrace(); 225 } catch (IOException e) { 226 e.printStackTrace(); 227 } finally { 228 // 关闭连接,释放资源 229 try { 230 httpclient.close(); 231 } catch (IOException e) { 232 e.printStackTrace(); 233 } 234 } 235 } 236 237 /** 238 * 上传文件 239 */ 240 public void upload() { 241 CloseableHttpClient httpclient = HttpClients.createDefault(); 242 try { 243 HttpPost httppost = new HttpPost("http://localhost:8080/myDemo/Ajax/serivceFile.action"); 244 245 FileBody bin = new FileBody(new File("F:\\image\\sendpix0.jpg")); 246 StringBody comment = new StringBody("A binary file of some kind", ContentType.TEXT_PLAIN); 247 248 HttpEntity reqEntity = MultipartEntityBuilder.create().addPart("bin", bin).addPart("comment", comment).build(); 249 250 httppost.setEntity(reqEntity); 251 252 System.out.println("executing request " + httppost.getRequestLine()); 253 CloseableHttpResponse response = httpclient.execute(httppost); 254 try { 255 System.out.println("----------------------------------------"); 256 System.out.println(response.getStatusLine()); 257 HttpEntity resEntity = response.getEntity(); 258 if (resEntity != null) { 259 System.out.println("Response content length: " + resEntity.getContentLength()); 260 } 261 EntityUtils.consume(resEntity); 262 } finally { 263 response.close(); 264 } 265 } catch (ClientProtocolException e) { 266 e.printStackTrace(); 267 } catch (IOException e) { 268 e.printStackTrace(); 269 } finally { 270 try { 271 httpclient.close(); 272 } catch (IOException e) { 273 e.printStackTrace(); 274 } 275 } 276 } 277 }</namevaluepair></namevaluepair></namevaluepair></namevaluepair>
