Android基礎入門教程——7.1.4 Android HTTP請求方式-HttpClient
Android基礎入門教程——7.1.4 Android HTTP請求方式:HttpClient
標籤(空格分隔): Android基礎入門教程
本節引言:
在上一節中我們對HttpURLConnection進行了學習,本節到第二種方式:HttpClient,儘管被Google
棄用了,但是我們我們平時也可以拿HttpClient來抓下包,配合Jsoup解析網頁效果更佳!HttpClient
用於接收/傳送Http請求/響應,但不快取伺服器響應,不執行HTML頁面潛入的JS程式碼,不會對頁面內容
進行任何解析,處理!開始本節內容!
1.HttpClient使用流程
基本流程:
2.HttpClient使用示例
1)使用HttpClient傳送GET請求
直接貼下簡單的傳送Get請求的程式碼:
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();
}
}
執行截圖:
另外,如果是帶有引數的GET請求的話,我們可以將引數放到一個List集合中,再對引數進行URL編碼,
最後和URL拼接下就好了:
List<BasicNameValuePair> params = new LinkedList<BasicNameValuePair>();
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傳送POST請求
POST請求比GET稍微複雜一點,建立完HttpPost物件後,通過NameValuePair集合來儲存等待提交
的引數,並將引數傳遞到UrlEncodedFormEntity中,最後呼叫setEntity(entity)完成,
HttpClient.execute(HttpPost)即可;這裡就不寫例子了,暫時沒找到Post的網站,又不想
自己寫個Servlet,So,直接貼核心程式碼吧~
核心程式碼:
private void PostByHttpClient(final String url)
{
new Thread()
{
public void run()
{
try{
HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
List<NameValuePair> params = new ArrayList<NameValuePair>();
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抓資料示例(教務系統資料抓取)
其實關於HttpClient的例子有很多,比如筆者曾經用它來抓學校教務系統上學生的課程表:
這就涉及到Cookie,模擬登陸的東西,說到抓資料(爬蟲),一般我們是搭配著JSoup來解析
抓到資料的,有興趣可以自己查閱相關資料,這裡貼下筆者畢設app裡獲取網頁部分的關鍵
程式碼!大家可以體會下:
HttpClient可以通過下述程式碼獲取與設定Cookie:
HttpResponse loginResponse = new DefaultHttpClient().execute(getLogin);
獲得Cookie:cookie = loginResponse.getFirstHeader(“Set-Cookie”).getValue();
請求時帶上Cookie**:httpPost.setHeader(“Cookie”, cookie);**
//獲得連結,模擬登入的實現:
public int getConnect(String user, String key) throws Exception {
// 先發送get請求 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);
// 獲取響應的cookie值
cookie = loginResponse.getFirstHeader("Set-Cookie").getValue();
System.out.println("cookie= " + cookie);
}
// 第二步:模擬登入
// 傳送Post請求,禁止重定向
HttpPost httpPost = new HttpPost(true_url);
httpPost.getParams().setParameter(ClientPNames.HANDLE_REDIRECTS, false);
// 設定Post提交的頭資訊的引數
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);
// 設定請求資料
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("__VIEWSTATE",
getViewState(loginhtml)));// __VIEWSTATE引數,如果變化可以動態抓取獲取
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,竟然不需要驗證碼
// 設定編碼方式,響應請求,獲取響應狀態碼:
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);
// 重定向狀態碼為302
if (Status == 302 || Status == 301) {
// 獲取頭部資訊中Location的值
location = response.getFirstHeader("Location").getValue();
System.out.println(location);
// 第三步:獲取管理資訊的主頁面
// Get請求
HttpGet httpGet = new HttpGet(ip_url + location);// 帶上location地址訪問
httpGet.setHeader("Referer", true_url);
httpGet.setHeader("Cookie", cookie);
// 主頁的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傳送Put請求
示例程式碼如下:
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<NameValuePair> params = new ArrayList<NameValuePair>();
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;
}
本節小結:
好的,本節關於Android HTTP的第二種請求方式:HttpClient就到這裡,
而基本請求也到這裡,下節開始我們將帶大家來學習XML以及Json的解析!
謝謝~