Android HTTP請(qǐng)求方式:HttpClient
本節(jié)引言:
在上一節(jié)中我們對(duì)HttpURLConnection進(jìn)行了學(xué)習(xí),本節(jié)到第二種方式:HttpClient,盡管被Google 棄用了,但是我們我們平時(shí)也可以拿HttpClient來(lái)抓下包,配合Jsoup解析網(wǎng)頁(yè)效果更佳!HttpClient 用于接收/發(fā)送Http請(qǐng)求/響應(yīng),但不緩存服務(wù)器響應(yīng),不執(zhí)行HTML頁(yè)面潛入的JS代碼,不會(huì)對(duì)頁(yè)面內(nèi)容 進(jìn)行任何解析,處理!開(kāi)始本節(jié)內(nèi)容!
1.HttpClient使用流程
基本流程:
2.HttpClient使用示例
1)使用HttpClient發(fā)送GET請(qǐng)求
直接貼下簡(jiǎn)單的發(fā)送Get請(qǐng)求的代碼:
public class MainActivity extends Activity implements OnClickListener { private Button btnGet; private WebView wView; public static final int SHOW_DATA = 0X123; private String detail = ""; private Handler handler = new Handler() { public void handleMessage(Message msg) { if(msg.what == SHOW_DATA) { wView.loadDataWithBaseURL("",detail, "text/html","UTF-8",""); } }; }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initView(); setView(); } private void initView() { btnGet = (Button) findViewById(R.id.btnGet); wView = (WebView) findViewById(R.id.wView); } private void setView() { btnGet.setOnClickListener(this); wView.getSettings().setDomStorageEnabled(true); } @Override public void onClick(View v) { if (v.getId() == R.id.btnGet) { GetByHttpClient(); } } private void GetByHttpClient() { new Thread() { public void run() { try { HttpClient httpClient = new DefaultHttpClient(); HttpGet httpGet = new HttpGet("http://www.w3cschool.cc/python/python-tutorial.html"); HttpResponse httpResponse = httpClient.execute(httpGet); if (httpResponse.getStatusLine().getStatusCode() == 200) { HttpEntity entity = httpResponse.getEntity(); detail = EntityUtils.toString(entity, "utf-8"); handler.sendEmptyMessage(SHOW_DATA); } } catch (Exception e) { e.printStackTrace(); } }; }.start(); } }
另外,如果是帶有參數(shù)的GET請(qǐng)求的話,我們可以將參數(shù)放到一個(gè)List集合中,再對(duì)參數(shù)進(jìn)行URL編碼, 最后和URL拼接下就好了:
List params = new LinkedList(); params.add(new BasicNameValuePair("user", "豬小弟")); params.add(new BasicNameValuePair("pawd", "123")); String param = URLEncodedUtils.format(params, "UTF-8"); HttpGet httpGet = new HttpGet("http://www.baidu.com"+"?"+param);
2)使用HttpClient發(fā)送POST請(qǐng)求
POST請(qǐng)求比GET稍微復(fù)雜一點(diǎn),創(chuàng)建完HttpPost對(duì)象后,通過(guò)NameValuePair集合來(lái)存儲(chǔ)等待提交 的參數(shù),并將參數(shù)傳遞到UrlEncodedFormEntity中,最后調(diào)用setEntity(entity)完成, HttpClient.execute(HttpPost)即可;這里就不寫(xiě)例子了,暫時(shí)沒(méi)找到Post的網(wǎng)站,又不想 自己寫(xiě)個(gè)Servlet,So,直接貼核心代碼吧~
核心代碼:
private void PostByHttpClient(final String url) { new Thread() { public void run() { try{ HttpClient httpClient = new DefaultHttpClient(); HttpPost httpPost = new HttpPost(url); List params = new ArrayList(); params.add(new BasicNameValuePair("user", "豬大哥")); params.add(new BasicNameValuePair("pawd", "123")); UrlEncodedFormEntity entity = new UrlEncodedFormEntity(params,"UTF-8"); httpPost.setEntity(entity); HttpResponse httpResponse = httpClient.execute(httpPost); if (httpResponse.getStatusLine().getStatusCode() == 200) { HttpEntity entity2 = httpResponse.getEntity(); detail = EntityUtils.toString(entity2, "utf-8"); handler.sendEmptyMessage(SHOW_DATA); } }catch(Exception e){e.printStackTrace();} }; }.start(); }
3.HttpClient抓數(shù)據(jù)示例(教務(wù)系統(tǒng)數(shù)據(jù)抓取)
其實(shí)關(guān)于HttpClient的例子有很多,比如筆者曾經(jīng)用它來(lái)抓學(xué)校教務(wù)系統(tǒng)上學(xué)生的課程表: 這就涉及到Cookie,模擬登陸的東西,說(shuō)到抓數(shù)據(jù)(爬蟲(chóng)),一般我們是搭配著JSoup來(lái)解析 抓到數(shù)據(jù)的,有興趣可以自己查閱相關(guān)資料,這里貼下筆者畢設(shè)app里獲取網(wǎng)頁(yè)部分的關(guān)鍵 代碼!大家可以體會(huì)下:
HttpClient可以通過(guò)下述代碼獲取與設(shè)置Cookie:HttpResponse loginResponse = new DefaultHttpClient().execute(getLogin);獲得Cookie:cookie = loginResponse.getFirstHeader("Set-Cookie").getValue();請(qǐng)求時(shí)帶上Cookie:httpPost.setHeader("Cookie", cookie);
//獲得鏈接,模擬登錄的實(shí)現(xiàn): public int getConnect(String user, String key) throws Exception { // 先發(fā)送get請(qǐng)求 獲取cookie值和__ViewState值 HttpGet getLogin = new HttpGet(true_url); // 第一步:主要的HTML: String loginhtml = ""; HttpResponse loginResponse = new DefaultHttpClient().execute(getLogin); if (loginResponse.getStatusLine().getStatusCode() == 200) { HttpEntity entity = loginResponse.getEntity(); loginhtml = EntityUtils.toString(entity); // 獲取響應(yīng)的cookie值 cookie = loginResponse.getFirstHeader("Set-Cookie").getValue(); System.out.println("cookie= " + cookie); } // 第二步:模擬登錄 // 發(fā)送Post請(qǐng)求,禁止重定向 HttpPost httpPost = new HttpPost(true_url); httpPost.getParams().setParameter(ClientPNames.HANDLE_REDIRECTS, false); // 設(shè)置Post提交的頭信息的參數(shù) httpPost.setHeader("User-Agent", "Mozilla/5.0 (Windows NT 6.3; WOW64; Trident/7.0; rv:11.0) like Gecko"); httpPost.setHeader("Referer", true_url); httpPost.setHeader("Cookie", cookie); // 設(shè)置請(qǐng)求數(shù)據(jù) List params = new ArrayList(); params.add(new BasicNameValuePair("__VIEWSTATE", getViewState(loginhtml)));// __VIEWSTATE參數(shù),如果變化可以動(dòng)態(tài)抓取獲取 params.add(new BasicNameValuePair("Button1", "")); params.add(new BasicNameValuePair("hidPdrs", "")); params.add(new BasicNameValuePair("hidsc", "")); params.add(new BasicNameValuePair("lbLanguage", "")); params.add(new BasicNameValuePair("RadioButtonList1", "%D1%A7%C9%FA")); params.add(new BasicNameValuePair("txtUserName", user)); params.add(new BasicNameValuePair("TextBox2", key)); params.add(new BasicNameValuePair("txtSecretCode", "")); // ( ╯□╰ )逗比正方,竟然不需要驗(yàn)證碼 // 設(shè)置編碼方式,響應(yīng)請(qǐng)求,獲取響應(yīng)狀態(tài)碼: httpPost.setEntity(new UrlEncodedFormEntity(params, "gb2312")); HttpResponse response = new DefaultHttpClient().execute(httpPost); int Status = response.getStatusLine().getStatusCode(); if(Status == 200)return Status; System.out.println("Status= " + Status); // 重定向狀態(tài)碼為302 if (Status == 302 || Status == 301) { // 獲取頭部信息中Location的值 location = response.getFirstHeader("Location").getValue(); System.out.println(location); // 第三步:獲取管理信息的主頁(yè)面 // Get請(qǐng)求 HttpGet httpGet = new HttpGet(ip_url + location);// 帶上location地址訪問(wèn) httpGet.setHeader("Referer", true_url); httpGet.setHeader("Cookie", cookie); // 主頁(yè)的html mainhtml = ""; HttpResponse httpResponseget = new DefaultHttpClient() .execute(httpGet); if (httpResponseget.getStatusLine().getStatusCode() == 200) { HttpEntity entity = httpResponseget.getEntity(); mainhtml = EntityUtils.toString(entity); } } return Status; }
4.使用HttpPut發(fā)送Put請(qǐng)求
示例代碼如下:
public static int PutActCode(String actCode, String licPlate, Context mContext) { int resp = 0; String cookie = (String) SPUtils.get(mContext, "session", ""); HttpPut httpPut = new HttpPut(PUTACKCODE_URL); httpPut.setHeader("Cookie", cookie); try { List params = new ArrayList(); params.add(new BasicNameValuePair("activation_code", actCode)); params.add(new BasicNameValuePair("license_plate", licPlate)); httpPut.setEntity(new UrlEncodedFormEntity(params, "UTF-8")); HttpResponse course_response = new DefaultHttpClient().execute(httpPut); if (course_response.getStatusLine().getStatusCode() == 200) { HttpEntity entity2 = course_response.getEntity(); JSONObject jObject = new JSONObject(EntityUtils.toString(entity2)); resp = Integer.parseInt(jObject.getString("status_code")); return resp; } } catch (Exception e) { e.printStackTrace(); } return resp; }
本節(jié)小結(jié):
好的,本節(jié)關(guān)于Android HTTP的第二種請(qǐng)求方式:HttpClient就到這里, 下節(jié)開(kāi)始我們來(lái)學(xué)習(xí)XML以及Json的解析,本節(jié)就到這里,謝謝~