Android客户端与服务端交互

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。