Android客户端与服务端交互之登陆示例

今天了解了一下android客户端与服务端是怎样交互的，发现其实跟web有点类似吧，然后网上找了大神的登陆示例，是基于IntentService的

1.后台使用简单的servlet，支持GET或POST。这个servlet最终返回给前台一个字符串flag，值是true或false，表示登录是否成功。

  servlet使用之前需要配置，主义servlet的servlet-name要和servlet-mapping的servlet-name一致，否则找不到路径

 我是在myEclipse上创建的一个web service 项目，然后部署到tomcat服务器上以便android客户端访问

		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.然后我是在安卓的ADT上创建一个安卓项目， 建立两个Activity，分别作为登录界面和登录成功界面。

3.HTTP的访问公共类，用于处理GET和POST请求

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 {
	// 创建HttpClient对象
	public static HttpClient httpClient = new DefaultHttpClient();
	public static final String BASE_URL = "http://192.168.3.14:8090/HelloWord/";

	/**
	 * 
	 * @param url
	 *            发送请求的URL
	 * @return 服务器响应字符串
	 * @throws Exception
	 */
	public static String getRequest(String url) throws Exception {
		// 创建HttpGet对象。
		HttpGet get = new HttpGet(url);
		// 发送GET请求
		HttpResponse httpResponse = httpClient.execute(get);
		// 如果服务器成功地返回响应
		if (httpResponse.getStatusLine().getStatusCode() == 200) {
			// 获取服务器响应字符串
			String result = EntityUtils.toString(httpResponse.getEntity());
			return result;
		} else {
			Log.d("服务器响应代码", (new Integer(httpResponse.getStatusLine()
					.getStatusCode())).toString());
			return null;
		}
	}

	/**
	 * 
	 * @param url
	 *            发送请求的URL
	 * @param params
	 *            请求参数
	 * @return 服务器响应字符串
	 * @throws Exception
	 */
	public static String postRequest(String url, Map rawParams)
			throws Exception {
		// 创建HttpPost对象。
		HttpPost post = new HttpPost(url);
		// 如果传递参数个数比较多的话可以对传递的参数进行封装
		List params = new ArrayList();
		for (String key : rawParams.keySet()) {
			// 封装请求参数
			params.add(new BasicNameValuePair(key, rawParams.get(key)));
		}
		// 设置请求参数
		post.setEntity(new UrlEncodedFormEntity(params, "UTF-8"));
		// 发送POST请求
		HttpResponse httpResponse = httpClient.execute(post);
		// 如果服务器成功地返回响应
		if (httpResponse.getStatusLine().getStatusCode() == 200) {
			// 获取服务器响应字符串
			String result = EntityUtils.toString(httpResponse.getEntity());
			return result;
		}
		return null;
	}
}

4. IntentService服务，用于在后台以队列方式处理耗时操作。

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
		/** 
         * 经测试，IntentService里面是可以进行耗时的操作的  
         * IntentService使用队列的方式将请求的Intent加入队列， 
         * 然后开启一个worker thread(线程)来处理队列中的Intent   
         * 对于异步的startService请求，IntentService会处理完成一个之后再处理第二个   
         */  
        Boolean flag = false;  
        //通过intent获取主线程传来的用户名和密码字符串  
        String username = intent.getStringExtra("username");  
        String password = intent.getStringExtra("password");  
        flag = doLogin(username, password);  
        Log.d("登录结果", flag.toString());  
          
        Intent broadcastIntent = new Intent();  
        broadcastIntent.setAction(ACTION_RECV_MSG);    
        broadcastIntent.addCategory(Intent.CATEGORY_DEFAULT);    
        broadcastIntent.putExtra("result", flag.toString());  
        sendBroadcast(broadcastIntent);  

	}
	
	 // 定义发送请求的方法  
    private Boolean doLogin(String username, String password)  
    {  
        String strFlag = "";  
        // 使用Map封装请求参数  
        HashMap map = new HashMap();  
        map.put("un", username);  
        map.put("pw", password);  
        // 定义发送请求的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 {  
            // 发送请求  
            strFlag = HttpUtil.postRequest(url, map);  //POST方式  
//          strFlag = HttpUtil.getRequest(url);  //GET方式  
            Log.d("服务器返回值", 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中注册IntentService。注意uses-permission节点，为程序开启访问网络的权限。

6.登陆界面处理，注意

1. 按钮监听事件中，使用Intent将要传递的值传给service。
2. 接收广播类中，同样使用Intent将要传递的值传给下一个Activity。
3. 在onCreate()中，动态注册接收广播类的实例receiver。
4. 在接收广播类中，不要使用完毕后忘记注销接收器，否则会报一个Are you missing a call to unregisterReceiver()? 的异常。

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();
		//动态注册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())
				{
					// 如果校验成功  
                    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, "账号不能为空",Toast.LENGTH_SHORT).show();
			return false;
		}
		if(passWord.equals(""))
		{
			Toast.makeText(MainActivity.this, "密码不能为空",Toast.LENGTH_SHORT).show();
			return false;
		}
		return true;
	}
	//接收广播类    
    public class MessageReceiver extends BroadcastReceiver {    
        @Override    
        public void onReceive(Context context, Intent intent) {    
           String message = intent.getStringExtra("result");    
           Log.i("MessageReceiver", message);  
        // 如果登录成功  
            if (message.equals("true")){  
                // 启动Main Activity  
                Intent nextIntent = new Intent(MainActivity.this, NaviActivity.class);  
                startActivity(nextIntent);  
                // 结束该Activity  
                finish();  
                //注销广播接收器  
                context.unregisterReceiver(this);  
            }else{  
            	Toast.makeText(MainActivity.this, "用户名或密码错误，请重新输入!",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;
	}

}

运行截图：

转载自http://blog.csdn.net/softwave