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>