Android用戶端和伺服器端資料互動的第三種方法

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        網上有很多例子來示範Android用戶端和伺服器端資料如何?互動不過這些例子大多比較繁雜，對於初學者來說這是不利的，現在介紹幾種代碼簡單、邏輯清晰的互動例子，本篇部落格介紹第三種：

        一、伺服器端：

        代碼1：添加名為“AndroidServerServlet.java”的檔案

package com.ghj.packageofservlet;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;public class AndroidServerServlet extends HttpServlet {private static final long serialVersionUID = 6792396567928634227L;public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {response.setContentType("text/plain; charset=UTF-8");request.setCharacterEncoding("UTF-8");System.err.println(request.getParameter("clientData"));PrintWriter printWriter = response.getWriter();printWriter.print("您好Android用戶端！");printWriter.flush();printWriter.close();}}

        代碼2：修改名為“web.xml”的檔案

<?xml version="1.0" encoding="UTF-8"?><web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"><servlet><servlet-name>AndroidServerServlet</servlet-name><servlet-class>com.ghj.packageofservlet.AndroidServerServlet</servlet-class></servlet><servlet-mapping><servlet-name>AndroidServerServlet</servlet-name><url-pattern>/AndroidServerServlet</url-pattern></servlet-mapping></web-app>

        二、Android手機用戶端：

        代碼1：添加名為“AndroidClientActivity.java”的檔案

package com.example.androidclient;import java.io.IOException;import java.io.UnsupportedEncodingException;import java.util.ArrayList;import java.util.List;import org.apache.http.HttpResponse;import org.apache.http.NameValuePair;import org.apache.http.client.ClientProtocolException;import org.apache.http.client.HttpClient;import org.apache.http.client.entity.UrlEncodedFormEntity;import org.apache.http.client.methods.HttpPost;import org.apache.http.impl.client.DefaultHttpClient;import org.apache.http.message.BasicNameValuePair;import org.apache.http.protocol.HTTP;import org.apache.http.util.EntityUtils;import android.app.Activity;import android.os.Bundle;import android.os.Looper;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.Toast;public class AndroidClientActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.android_client);Button sendButton = (Button) findViewById(R.id.send_button);sendButton.setOnClickListener(new OnClickListener(){@Overridepublic void onClick(View v) {new Thread(new Runnable(){    @Override    public void run() {    Looper.prepare();    HttpPost httpRequest = new HttpPost("http://172.16.99.207:8080/AndroidServer/AndroidServerServlet");    List<NameValuePair> params = new ArrayList<NameValuePair>();    params.add(new BasicNameValuePair("clientData", "您好伺服器端！"));    try {    httpRequest.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));//佈建要求參數項                HttpClient httpClient = new DefaultHttpClient();                HttpResponse httpResponse = httpClient.execute(httpRequest);//執行請求返迴響應                if(httpResponse.getStatusLine().getStatusCode() == 200){//判斷是否請求成功                Toast.makeText(AndroidClientActivity.this, EntityUtils.toString(httpResponse.getEntity()), Toast.LENGTH_LONG).show();                }else{                Toast.makeText(AndroidClientActivity.this, "沒有擷取到Android伺服器端的響應！", Toast.LENGTH_LONG).show();                }            } catch (ClientProtocolException e) {            e.printStackTrace();    } catch (UnsupportedEncodingException e) {    e.printStackTrace();    } catch (IOException e) {    e.printStackTrace();    }    Looper.loop();    }}).start();}});}}

         注意：上面代碼第41行和第61行不可缺少，否則會出現java.lang.RuntimeException: Can‘t create handler inside thread that has not called Looper.prepare()異常，關於該異常請參見另一篇名為《Android中的Can‘t create handler inside thread that has not called Looper.prepare()異常》部落格。

        代碼2：添加名為“android_client.xml”的檔案

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="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" >   <Button       android:id="@+id/send_button"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:layout_centerHorizontal="true"       android:layout_centerVertical="true"       android:text="@string/hello_server" /></RelativeLayout>

       【0分下載該Demo】

Android用戶端和伺服器端資料互動的第三種方法