編輯：關於Android編程
HttpClient與服務器數據交互方式：HttpPost和HttpGet 分別對應Post和Get提交。因為要做Android客戶端的緣故，所以就必須實現客戶端與服務器實現數據交互，以保證數據鏈條的通暢，實現數據閉環。由於之前對Android客戶端訪問web數據沒有設置權限，所以可以很好的訪問系統資源，但是如果是開發應用這種方式就存在極大的安全隱患，一個Host或Get提交過去數據就獲取到了，web端系統完全就是裸奔。所以web端權限管理很有必要，也就不用過於擔心Android客戶端帶來的安全隱患。Android新手學習一般都會遇到問題，前兩天就遇到web端設置了權限而Android客戶端發起訪問獲取不到數據的問題。
編寫一個測試Activity，MainActivity.
package com.boonya.httpclienttest;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.protocol.HTTP;
import org.json.JSONArray;
import org.json.JSONObject;
import com.boonya.httpclienttest.utils.HtttpClientUtil;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;
public class MainActivity extends Activity
{
private static final String TAG = MainActivity;
private List> videos = null;
private HashMap video = null;
private ListView listView = null;
private static String loginurl = http://192.168.1.147:8090/wtms/androidservice/login;
private static String getdataurl = http://192.168.1.147:8090/wtms/androidservice/videos.avd;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
listView = (ListView) findViewById(R.id.videos);
postMethod();
getMethod();
}
/**
* HttpGet獲取服務器數據顯示
*
* @param url
*/
protected void getMethod()
{
HttpGet request = new HttpGet(getdataurl);
//request.setHeader(Cookie, HtttpClientUtil.getCookie());//設置cookie
try
{
//設置請求參數項
//request.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));
HttpClient client = HtttpClientUtil.getInstance();
//執行請求返回相應
HttpResponse response = client.execute(request);
// 判斷請求是否成功
if (response.getStatusLine().getStatusCode() == 200)
{ // 200表示請求成功
StringBuilder builder = new StringBuilder();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
String s = null;
while ((s = bufferedReader.readLine()) != null)
{
builder.append(s);
}
// String out = EntityUtils.toString(entity, UTF-8);
String msg = builder.toString();
Log.d(log, >>>>執行 方法 getMethod()獲取到范圍值：+msg);
JSONArray jsonArray = new JSONArray(msg);
videos = new ArrayList>();
for (int i = 0; i < jsonArray.length(); i++)
{
JSONObject jsonObject = (JSONObject) jsonArray.get(i);
int id = jsonObject.getInt(id);
String name = jsonObject.getString(name);
int timelength = jsonObject.getInt(time);
video = new HashMap();
video.put(id, id);
video.put(name, name);
video.put(timelength, 時長為: + timelength);
videos.add(video);
}
SimpleAdapter adapter = new SimpleAdapter(this, videos, R.layout.item, new String[]
{ name, timelength }, new int[]
{ R.id.title, R.id.timelength });
listView.setAdapter(adapter);
}
} catch (Exception e)
{
e.printStackTrace();
Log.e(TAG, e.toString());
Toast.makeText(MainActivity.this, 獲取數據失敗, Toast.LENGTH_LONG).show();
}
}
/**
* HttpPost提交數據
*/
@SuppressWarnings(
{ unchecked, rawtypes })
protected void postMethod()
{
try
{
// 使用ApacheHttp客戶端進行連接(重要方法)
HttpClient client = HtttpClientUtil.getInstance();
// 如果是Get提交則創建HttpGet對象，否則創建HttpPost對象
// POST提交的方式
HttpPost request = new HttpPost(loginurl);
// 如果是Post提交可以將參數封裝到集合中傳遞
List params = new ArrayList();
params.add(new BasicNameValuePair(username, test));
params.add(new BasicNameValuePair(password, test));
// UrlEncodedFormEntity用於將集合轉換為Entity對象
request.setEntity(new UrlEncodedFormEntity(params,HTTP.UTF_8));
try
{
// 獲取相應消息
HttpResponse response = client.execute(request);
StringBuilder builder = new StringBuilder();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
// 操作cookie
/* List cookies = ((AbstractHttpClient) client).getCookieStore().getCookies();
if(cookies!=null&&cookies.size()>0)
{
for (int i = 0; i < cookies.size(); i++)
{
HtttpClientUtil.setCookie(cookies.get(i).getValue());
}
}*/
String s =null;
while((s = bufferedReader.readLine())!=null){
builder.append(s);
}
String string=builder.toString();
Log.d(log, >>>>執行 方法 postMethod()獲取到范圍值：+string);
} catch (ClientProtocolException e)
{
e.printStackTrace();
} catch (IOException e)
{
e.printStackTrace();
}
} catch (UnsupportedEncodingException e)
{
e.printStackTrace();
}
}
}
這裡采用單例模式實現HttpClient對象在Android客戶端的唯一性，用戶在登錄系統後，這個對象會記錄用戶的Cookie，一旦建立客戶端與服務器的訪問認證，以後就可以任意發送HTTP請求到服務器請求或操作資源了。
package com.boonya.httpclienttest.utils;
import org.apache.http.client.HttpClient;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpConnectionParams;
public class HtttpClientUtil
{
/** 設置請求超時10秒鐘 */
private static final int REQUEST_TIMEOUT = 10 * 1000;
/** 設置等待數據超時時間10秒鐘 */
private static final int SO_TIMEOUT = 10 * 1000;
private static HttpClient instance;
/** 記住cookie字符串*/
private static String cookie;
/**
* 自定義方法：初始化HttpClient，並設置超時
*
* @return 返回：HttpClient 對象
*/
private HtttpClientUtil()
{
}
public static String getCookie()
{
return cookie;
}
public static void setCookie(String cookie)
{
HtttpClientUtil.cookie = cookie;
}
public static HttpClient getInstance()
{
if (instance == null)
{
BasicHttpParams httpParams = new BasicHttpParams();
HttpConnectionParams.setConnectionTimeout(httpParams, REQUEST_TIMEOUT);
HttpConnectionParams.setSoTimeout(httpParams, SO_TIMEOUT);
instance = new DefaultHttpClient(httpParams);
}
return instance;
}
}
上面cookie字段並非必須的，如果HttpClient不是單例的，那麼用戶需要在靜態變量來記住登錄後的cookie。
優化HttpClientUtil的cookie獲取方法：
package com.boonya.httpclienttest.utils;
import java.util.List;
import org.apache.http.client.HttpClient;
import org.apache.http.cookie.Cookie;
import org.apache.http.impl.client.AbstractHttpClient;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpConnectionParams;
public class HtttpClientUtil
{
/** 設置請求超時10秒鐘 */
private static final int REQUEST_TIMEOUT = 10 * 1000;
/** 設置等待數據超時時間10秒鐘 */
private static final int SO_TIMEOUT = 10 * 1000;
private static HttpClient instance;
/** 記住cookie字符串 */
private static String cookie = null;
/**
* 自定義方法：初始化HttpClient，並設置超時
*
* @return 返回：HttpClient 對象
*/
private HtttpClientUtil()
{
}
public static String getCookie()
{
// 確保實例存在
HtttpClientUtil.getInstance();
// 獲取cookie
List cookies = ((AbstractHttpClient) instance).getCookieStore().getCookies();
if (cookies != null && cookies.size() > 0)
{
for (int i = 0; i < cookies.size(); i++)
{
cookie = cookies.get(i).getValue();
}
}
return cookie;
}
public static HttpClient getInstance()
{
if (instance == null)
{
BasicHttpParams httpParams = new BasicHttpParams();
HttpConnectionParams.setConnectionTimeout(httpParams, REQUEST_TIMEOUT);
HttpConnectionParams.setSoTimeout(httpParams, SO_TIMEOUT);
instance = new DefaultHttpClient(httpParams);
}
return instance;
}
}
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