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Android客户端与服务端交互

时间：2021-12-08 13:18:22 | 栏目：Android代码 | 点击：次

本文和大家一起了解了一下android客户端与服务端是怎样交互的，具体内容如下

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

<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>

 
 

 

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。

<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="http://schemas.android.com/apk/res/android" xmlns:tools="http://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>

 
 

 

<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="http://schemas.android.com/apk/res/android" xmlns:tools="http://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。

 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<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。

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。 

<!--?xml version=1.0 encoding=utf-8?-->

<manifest android:versioncode="1" android:versionname="1.0" package="com.example.logindemo" xmlns:android="http://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

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。 

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;

  }

 

}

以上就是本文的全部内容，希望对大家的学习有所帮助。

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