Android 客户端与服务端交互之登陆示例（Android+servlet+JavaBean+tomcat）

其他 2019-03-28 02:24:35 阅读次数: 0

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

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<servlet>
         <servlet-name>helloWorld</servlet-name>
         <servlet- class >com.zhongzhong.wap.action.HelloServlet</servlet- class >
     </servlet>
     <servlet-mapping>
         <servlet-name>helloWorld</servlet-name>
         <url-pattern>/queryOrder</url-pattern>
     </servlet-mapping>



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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。

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<relativelayout android:layout_height= "match_parent" android:layout_width= "match_parent" android:paddingbottom= "@dimen/activity_vertical_margin" android:paddingleft= "@dimen/activity_horizontal_margin" android:paddingright= "@dimen/activity_horizontal_margin" android:paddingtop= "@dimen/activity_vertical_margin" tools:context= ".MainActivity" xmlns:android= "https://schemas.android.com/apk/res/android" xmlns:tools= "https://schemas.android.com/tools" >
 
     <textview android:id= "@+id/textView1" android:layout_alignparenttop= "true" android:layout_centerhorizontal= "true" android:layout_height= "wrap_content" android:layout_margintop= "40dp" android:layout_width= "wrap_content" android:text= "HelloWorld登陆示例" >
 
     <edittext android:ems= "10" android:hint= "请输入账号" android:id= "@+id/et_user" android:layout_below= "@+id/textView1" android:layout_centerhorizontal= "true" android:layout_height= "wrap_content" android:layout_margintop= "33dp" android:layout_width= "wrap_content" >
 
         <requestfocus>
     </requestfocus></edittext>
 
     <edittext android:ems= "10" android:hint= "请输入密码" android:id= "@+id/et_psw" android:inputtype= "textPassword" android:layout_below= "@+id/et_user" android:layout_centerhorizontal= "true" android:layout_height= "wrap_content" android:layout_margintop= "40dp" android:layout_width= "wrap_content" ><button android:id= "@+id/btn_login" android:layout_below= "@+id/et_psw" android:layout_centerhorizontal= "true" android:layout_height= "wrap_content" android:layout_margintop= "37dp" android:layout_width= "wrap_content" android:text= "登陆" ></button></edittext></textview></relativelayout>


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<relativelayout android:layout_height= "match_parent" android:layout_width= "match_parent" android:paddingbottom= "@dimen/activity_vertical_margin" android:paddingleft= "@dimen/activity_horizontal_margin" android:paddingright= "@dimen/activity_horizontal_margin" android:paddingtop= "@dimen/activity_vertical_margin" tools:context= ".NaviActivity" xmlns:android= "https://schemas.android.com/apk/res/android" xmlns:tools= "https://schemas.android.com/tools" >
 
     <textview android:layout_alignparenttop= "true" android:layout_centerhorizontal= "true" android:layout_height= "wrap_content" android:layout_margintop= "46dp" android:layout_width= "wrap_content" android:text= "登陆成功" >
 
</textview></relativelayout>



3.HTTP 的访问公共类，用于处理 GET 和 POST 请求

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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 = https: //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<string, string= "" > 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<namevaluepair> params = new ArrayList<namevaluepair>();
         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 ;
     }
}
</namevaluepair></namevaluepair></string,>


4.IntentService 服务，用于在后台以队列方式处理耗时操作。

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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<string, string= "" > map = new HashMap<string, string= "" >(); 
         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 ; 
         } 
           
     } 
}
</string,></string,>


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。

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<!--?xml version= 1.0 encoding=utf- 8 ?-->
<manifest android:versioncode= "1" android:versionname= "1.0" package = "com.example.logindemo" xmlns:android= "https://schemas.android.com/apk/res/android" >
 
     <uses-sdk android:minsdkversion= "8" android:targetsdkversion= "18" >
 
     <uses-permission android:name= "android.permission.INTERNET" >
 
     
         
             <intent-filter>
                 
 
                 <category android:name= "android.intent.category.LAUNCHER" >
             </category></action></intent-filter>
         </activity>
         
         </activity>
 
         <service android:name= "com.example.logindemo.ConnectService" >
         </service>
     </application>
 
</uses-permission></uses-sdk></manifest>


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。接收广播类中，同样使用 Intent 将要传递的值传给下一个 Activity。在 onCreate() 中，动态注册接收广播类的实例 receiver。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。
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    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：

    \\

转自：https://www.2cto.com/kf/201408/328118.html

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