Android客戶端與服務端交互之登陸示例

今天了解了一下android客戶端與服務端是怎樣交互的，發現其實跟web有點類似吧，然後網上找了大神的登陸示例，是基於IntentService的

 

1.後台使用簡單的servlet，支持GET或POST。這個servlet最終返回給前台一個字符串flag，值是true或false，表示登錄是否成功。

servlet使用之前需要配置，主義servlet的servlet-name要和servlet-mapping的servlet-name一致，否則找不到路徑

我是在myEclipse上創建的一個web service 項目，然後部署到tomcat服務器上以便android客戶端訪問

 

		helloWorld
		com.zhongzhong.wap.action.HelloServlet
	
	
		helloWorld
		/queryOrder
	

 

 

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.zhongzhong.wap.bean.UserBean;

public class HelloServlet extends HttpServlet {

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		doPost(req, resp);
	}

	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		
		 resp.setContentType(text/html);  
	        PrintWriter out = resp.getWriter();  
	        Boolean flag = false;    
	        String userName = req.getParameter(un);  
	        String password = req.getParameter(pw);   
	        if(userName.equals(htp)&&password.equals(123))
	        {
	        	flag = true;
	        }
	        
	        else flag = false;
	        System.out.println(userName:+userName+ password:+password);
	        out.print(flag);  
	        out.flush();  
	        out.close(); 
	}

}

2.然後我是在安卓的ADT上創建一個安卓項目，建立兩個Activity，分別作為登錄界面和登錄成功界面。

 

 

 

3.HTTP的訪問公共類，用於處理GET和POST請求

 

package com.example.logindemo;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
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.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

import android.content.Entity;
import android.util.Log;

public class HttpUtil {
	// 創建HttpClient對象
	public static HttpClient httpClient = new DefaultHttpClient();
	public static final String BASE_URL = http://192.168.3.14:8090/HelloWord/;

	/**
	 * 
	 * @param url
	 *            發送請求的URL
	 * @return 服務器響應字符串
	 * @throws Exception
	 */
	public static String getRequest(String url) throws Exception {
		// 創建HttpGet對象。
		HttpGet get = new HttpGet(url);
		// 發送GET請求
		HttpResponse httpResponse = httpClient.execute(get);
		// 如果服務器成功地返回響應
		if (httpResponse.getStatusLine().getStatusCode() == 200) {
			// 獲取服務器響應字符串
			String result = EntityUtils.toString(httpResponse.getEntity());
			return result;
		} else {
			Log.d(服務器響應代碼, (new Integer(httpResponse.getStatusLine()
					.getStatusCode())).toString());
			return null;
		}
	}

	/**
	 * 
	 * @param url
	 *            發送請求的URL
	 * @param params
	 *            請求參數
	 * @return 服務器響應字符串
	 * @throws Exception
	 */
	public static String postRequest(String url, Map rawParams)
			throws Exception {
		// 創建HttpPost對象。
		HttpPost post = new HttpPost(url);
		// 如果傳遞參數個數比較多的話可以對傳遞的參數進行封裝
		List params = new ArrayList();
		for (String key : rawParams.keySet()) {
			// 封裝請求參數
			params.add(new BasicNameValuePair(key, rawParams.get(key)));
		}
		// 設置請求參數
		post.setEntity(new UrlEncodedFormEntity(params, UTF-8));
		// 發送POST請求
		HttpResponse httpResponse = httpClient.execute(post);
		// 如果服務器成功地返回響應
		if (httpResponse.getStatusLine().getStatusCode() == 200) {
			// 獲取服務器響應字符串
			String result = EntityUtils.toString(httpResponse.getEntity());
			return result;
		}
		return null;
	}
}

4.IntentService服務，用於在後台以隊列方式處理耗時操作。

 

 

package com.example.logindemo;

import java.util.HashMap;

import android.app.IntentService;
import android.content.Intent;
import android.util.Log;

public class ConnectService extends IntentService {
	private static final String ACTION_RECV_MSG = com.example.logindemo.action.RECEIVE_MESSAGE;

	public ConnectService() {
		super(TestIntentService);
		// TODO Auto-generated constructor stub
	}
	
	@Override
	protected void onHandleIntent(Intent intent) {
		// TODO Auto-generated method stub
		/** 
         * 經測試，IntentService裡面是可以進行耗時的操作的  
         * IntentService使用隊列的方式將請求的Intent加入隊列， 
         * 然後開啟一個worker thread(線程)來處理隊列中的Intent   
         * 對於異步的startService請求，IntentService會處理完成一個之後再處理第二個   
         */  
        Boolean flag = false;  
        //通過intent獲取主線程傳來的用戶名和密碼字符串  
        String username = intent.getStringExtra(username);  
        String password = intent.getStringExtra(password);  
        flag = doLogin(username, password);  
        Log.d(登錄結果, flag.toString());  
          
        Intent broadcastIntent = new Intent();  
        broadcastIntent.setAction(ACTION_RECV_MSG);    
        broadcastIntent.addCategory(Intent.CATEGORY_DEFAULT);    
        broadcastIntent.putExtra(result, flag.toString());  
        sendBroadcast(broadcastIntent);  

	}
	
	 // 定義發送請求的方法  
    private Boolean doLogin(String username, String password)  
    {  
        String strFlag = ;  
        // 使用Map封裝請求參數  
        HashMap map = new HashMap();  
        map.put(un, username);  
        map.put(pw, password);  
        // 定義發送請求的URL  
      String url = HttpUtil.BASE_URL + queryOrder?un= + username + &pw= + password;  //GET方式  
       // String url = HttpUtil.BASE_URL + LoginServlet; //POST方式  
        Log.d(url, url);  
        Log.d(username, username);  
        Log.d(password, password);  
        try {  
            // 發送請求  
            strFlag = HttpUtil.postRequest(url, map);  //POST方式  
//          strFlag = HttpUtil.getRequest(url);  //GET方式  
            Log.d(服務器返回值, strFlag);  
        } catch (Exception e) {  
            // TODO Auto-generated catch block  
            e.printStackTrace();  
        }  
          
        if(strFlag.trim().equals(true)){  
            return true;  
        }else{  
            return false;  
        }  
          
    }  
}

5。在AndroidManifest.xml中注冊IntentService。注意uses-permission節點，為程序開啟訪問網絡的權限。

 

 

6.登陸界面處理，注意

 

 

1. 按鈕監聽事件中，使用Intent將要傳遞的值傳給service。接收廣播類中，同樣使用Intent將要傳遞的值傳給下一個Activity。在onCreate()中，動態注冊接收廣播類的實例receiver。在接收廣播類中，不要使用完畢後忘記注銷接收器，否則會報一個Are you missing a call to unregisterReceiver()? 的異常。
   

    

    

   package com.example.logindemo;
   
   import android.os.Bundle;
   import android.app.Activity;
   import android.content.BroadcastReceiver;
   import android.content.Context;
   import android.content.Intent;
   import android.content.IntentFilter;
   import android.util.Log;
   import android.view.Menu;
   import android.view.View;
   import android.view.View.OnClickListener;
   import android.widget.Button;
   import android.widget.EditText;
   import android.widget.Toast;
   
   public class MainActivity extends Activity {
   	 private static final String ACTION_RECV_MSG = com.example.logindemo.action.RECEIVE_MESSAGE;
   	private Button loginBtn;
   	private EditText et_username;
   	private EditText et_password;
   	private String userName;
   	private String passWord;
   	private MessageReceiver receiver ;
   	@Override
   	protected void onCreate(Bundle savedInstanceState) {
   		super.onCreate(savedInstanceState);
   		setContentView(R.layout.activity_main);
   		initView();
   		//動態注冊receiver    
           IntentFilter filter = new IntentFilter(ACTION_RECV_MSG);    
           filter.addCategory(Intent.CATEGORY_DEFAULT);    
           receiver = new MessageReceiver();    
           registerReceiver(receiver, filter); 
   	}
   	
   	private void initView() {
   		// TODO Auto-generated method stub
   		et_username = (EditText)findViewById(R.id.et_user);
   		et_password =( EditText)findViewById(R.id.et_psw);
   		loginBtn = (Button)findViewById(R.id.btn_login);
   		loginBtn.setOnClickListener(new OnClickListener() {
   			
   			@Override
   			public void onClick(View v) {
   				// TODO Auto-generated method stub
   				if(matchLoginMsg())
   				{
   					// 如果校驗成功  
                       Intent msgIntent = new Intent(MainActivity.this, ConnectService.class);  
                       msgIntent.putExtra(username, et_username.getText().toString().trim());  
                       msgIntent.putExtra(password, et_password.getText().toString().trim());  
                       startService(msgIntent); 
   				}
   				
   			}
   		});
   	}
   	
   	protected boolean matchLoginMsg() {
   		// TODO Auto-generated method stub
   		userName = et_username.getText().toString().trim();
   		passWord = et_password.getText().toString().trim();
   		if(userName.equals())
   		{
   			Toast.makeText(MainActivity.this, 賬號不能為空,Toast.LENGTH_SHORT).show();
   			return false;
   		}
   		if(passWord.equals())
   		{
   			Toast.makeText(MainActivity.this, 密碼不能為空,Toast.LENGTH_SHORT).show();
   			return false;
   		}
   		return true;
   	}
   	//接收廣播類    
       public class MessageReceiver extends BroadcastReceiver {    
           @Override    
           public void onReceive(Context context, Intent intent) {    
              String message = intent.getStringExtra(result);    
              Log.i(MessageReceiver, message);  
           // 如果登錄成功  
               if (message.equals(true)){  
                   // 啟動Main Activity  
                   Intent nextIntent = new Intent(MainActivity.this, NaviActivity.class);  
                   startActivity(nextIntent);  
                   // 結束該Activity  
                   finish();  
                   //注銷廣播接收器  
                   context.unregisterReceiver(this);  
               }else{  
               	Toast.makeText(MainActivity.this, 用戶名或密碼錯誤，請重新輸入!,Toast.LENGTH_SHORT).show(); 
               }  
                 
           }    
       }    
   	@Override
   	public boolean onCreateOptionsMenu(Menu menu) {
   		// Inflate the menu; this adds items to the action bar if it is present.
   		getMenuInflater().inflate(R.menu.main, menu);
   		return true;
   	}
   
   }
   

   
   
   

    

   運行截圖：