《安卓网络编程》之第三篇 使用Apache接口

在Android系统中，提供了一下三种通信接口：

• 标准的Java 接口：java.net
• Apache接口：org.apache.http
• Android网络接口：android.net.http

在android系统中，包含了Apache HttpClient库，此库为执行Android中的网络操作之首选方法。

Apache应用基础

本文讲的Apache是一个中介，它只负责传递消息，至于具体怎么上网它概不负责。

联网流程

　　在Android系统中，可以采用HttpPost和HttpGet来封装Post请求和Get请求，然后再使用HttpClient的excute()方法发送Post或者get请求来返回服务器的响应数据。使用Apache联网的基本流程如下：

1. 设置连接和读取超时时间，并建立HttpClient对象
2. 实现Get请求
3. 实现Post发送请求处理
4. 使用Response响应请求

这样，使用Apache实现联网处理数据交互的过程就完成了，无论多么复杂的项目，都必须遵循上面的流程。

下面是一个运行在安卓上的工程实例：

 package irdc.httpSHI;
 
 /*必需引用apache.http相关类来建立HTTP联机*/
 import org.apache.http.HttpResponse;
 import org.apache.http.NameValuePair;
 import org.apache.http.client.ClientProtocolException;
 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.protocol.HTTP;
 import org.apache.http.util.EntityUtils;
 /*必需引用java.io 与java.util相关类?来读写档案*/
 import irdc.httpSHI.R;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 import android.app.Activity;
 import android.os.Bundle;
 import android.view.View;
 import android.widget.Button;
 import android.widget.TextView; 
 
 public class httpSHI extends Activity
 {
   /*宣╳两个Button物件,与几个TextView物件*/
   private Button mButton1,mButton2;
   private TextView mTextView1; 
 
   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState)
   {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.main); 
 
     /*透过findViewById建构巳建立TextView与Button对象*/
     mButton1 =(Button) findViewById(R.id.myButton1);
     mButton2 =(Button) findViewById(R.id.myButton2);
     mTextView1 = (TextView) findViewById(R.id.myTextView1); 
 
     mButton1.setOnClickListener(new Button.OnClickListener()
     { 
 
       @Override
       public void onClick(View v)
       { 
 
         String uriAPI = "http://www.baidu.com";
         /*建立HTTP Post联机*/
         HttpPost httpRequest = new HttpPost(uriAPI);
         /*
          * Post传送变量必须用NameValuePair[]存储
         */
         List <NameValuePair> params = new ArrayList <NameValuePair>();
         params.add(new BasicNameValuePair("str", "I am Post String"));
         try
         {
           /*发叨HTTP request*/
           httpRequest.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));
           /*取得HTTP response*/
           HttpResponse httpResponse = new DefaultHttpClient().execute(httpRequest);
           /*若状态码为200*/
           if(httpResponse.getStatusLine().getStatusCode() == 200)
           {
             /*获取字符串*/
             String strResult = EntityUtils.toString(httpResponse.getEntity());
             mTextView1.setText(strResult);
           }
           else
           {
             mTextView1.setText("Error Response: "+httpResponse.getStatusLine().toString());
           }
         }
         catch (ClientProtocolException e)
         {
           mTextView1.setText(e.getMessage().toString());
           e.printStackTrace();
         }
         catch (IOException e)
         {
           mTextView1.setText(e.getMessage().toString());
           e.printStackTrace();
         }
         catch (Exception e)
         {
           mTextView1.setText(e.getMessage().toString());
           e.printStackTrace();
         }  
 
       }
     });
     mButton2.setOnClickListener(new Button.OnClickListener()
     {
       @Override
       public void onClick(View v)
       {
         // TODO Auto-generated method stub
         String uriAPI = "http://www.baidu.com/str=I+am+Get+String";
         /*建立HTTP Get联机*/
         HttpGet httpRequest = new HttpGet(uriAPI);
         try
         {
           /*发送获取的HTTP request*/
           HttpResponse httpResponse = new DefaultHttpClient().execute(httpRequest);
           /*若状态码为200*/
           if(httpResponse.getStatusLine().getStatusCode() == 200)
           {
             /*取叨并应?串*/
             String strResult = EntityUtils.toString(httpResponse.getEntity());
             strResult = eregi_replace("(\r\n|\r|\n|\n\r)","",strResult);
             mTextView1.setText(strResult);
           }
           else
           {
             mTextView1.setText("Error Response: "+httpResponse.getStatusLine().toString());
           }
         }
         catch (ClientProtocolException e)
         {
           mTextView1.setText(e.getMessage().toString());
           e.printStackTrace();
         }
         catch (IOException e)
         {
           mTextView1.setText(e.getMessage().toString());
           e.printStackTrace();
         }
         catch (Exception e)
         {
           mTextView1.setText(e.getMessage().toString());
           e.printStackTrace();
         }
       }
     });
   }
     public String eregi_replace(String strFrom, String strTo, String strTarget)
     {
       String strPattern = "(?i)"+strFrom;
       Pattern p = Pattern.compile(strPattern);
       Matcher m = p.matcher(strTarget);
       if(m.find())
       {
         return strTarget.replaceAll(strFrom, strTo);
       }
       else
       {
         return strTarget;
       }
     }
 } 

实现了post和get俩种方式联网。

xml文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:background="@drawable/white"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
  <TextView
    android:id="@+id/myTextView1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/title"/>
  <Button
    android:id="@+id/myButton1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/str_button1" />
    <Button
    android:id="@+id/myButton2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/str_button2" />
</LinearLayout>