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【每日一博】Android 的三种网络通讯方式详解

‍ 1.标准Java接口

java.net.*提供与联网有关的类，包括流、数据包套接字(socket)、Internet协议、常见Http处理等。比如：创建URL，以及URLConnection/HttpURLConnection对象、设置链接参数、链接到服务器、向服务器写数据、从服务器读取数据等通信。这些在Java网络编程中均有涉及，我们看一个简单的socket编程，实现服务器回发客户端信息。

下面用个例子来说明：

A、客户端：

新建Android项目工程：SocketForAndroid（这个随意起名字了吧，我是以这个建立的！）

下面是main_activity.xml的代码：

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:layout_width="fill_parent"  android:layout_height="fill_parent"  android:orientation="vertical">  <TextView   android:layout_width="fill_parent"   android:layout_height="wrap_content"   android:text="@string/hello" />  <EditText   android:id="@+id/message"   android:layout_width="match_parent"   android:layout_height="wrap_content"   android:hint="@string/hint" />  <Button   android:id="@+id/send"   android:layout_width="fill_parent"   android:layout_height="wrap_content"   android:text="@string/send" /> </LinearLayout>

MainActivity.java的代码入下：

package com.yaowen.socketforandroid; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.view.View; import android.widget.Button; import android.widget.EditText; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.IOException; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.io.PrintWriter; import java.net.Socket; public class MainActivity extends AppCompatActivity {  private EditText message;  private Button send;  @Override  protected void onCreate(Bundle savedInstanceState) {   super.onCreate(savedInstanceState);   setContentView(R.layout.activity_main);   //初始化两个UI控件   message = (EditText) findViewById(R.id.message);   send = (Button) findViewById(R.id.send);   //设置发送按钮的点击事件响应   send.setOnClickListener(new View.OnClickListener() {    @Override    public void onClick(View v) {     Socket socket = null;     //获取message输入框里的输入的内容     String msg = message.getText().toString() + "/r/n";     try {      //这里必须是192.168.3.200，不可以是localhost或者127.0.0.1      socket = new Socket("192.168.3.200", 18888);      PrintWriter out = new PrintWriter(        new BufferedWriter(          new OutputStreamWriter(            socket.getOutputStream()          )        ), true);      //发送消息      out.println(msg);      //接收数据      BufferedReader in = new BufferedReader(       new InputStreamReader(        socket.getInputStream()       )      );      //读取接收的数据      String msg_in = in.readLine();      if (null != msg_in) {       message.setText(msg_in);       System.out.println(msg_in);      } else {       message.setText("接收的数据有误!");      }      //关闭各种流      out.close();      in.close();     } catch (IOException e) {      e.printStackTrace();     } finally {      try {       if (null != socket) {        //socket不为空时，最后记得要把socket关闭        socket.close();       }      } catch (IOException e) {       e.printStackTrace();      }     }    }   });  } }

最后别忘记添加访问网络权限：

<uses-permission android:name="android.permission.INTERNET" />

B、服务端：

package service; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.IOException; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.io.PrintWriter; import java.net.ServerSocket; import java.net.Socket; public class ServerAndroid implements Runnable {  @Override  public void run() {   Socket socket = null;   try {    ServerSocket server = new ServerSocket(18888);    // 循环监听客户端链接请求    while (true) {     System.out.println("start...");     // 接收请求     socket = server.accept();     System.out.println("accept...");     // 接收客户端消息     BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));     String message = in.readLine();     System.out.println(message);     // 发送消息，向客户端     PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())),       true);     out.println("Server:" + message);     // 关闭流     in.close();     out.close();    }   } catch (IOException e) {    e.printStackTrace();   } finally {    if (null != socket) {     try {      socket.close();     } catch (IOException e) {      e.printStackTrace();     }    }   }  }  // 启动服务器  public static void main(String[] args) {   Thread server = new Thread(new ServerAndroid());   server.start();  } }

C、启动服务器，控制台会打印出“start...”字符串！

D、运行Android项目文件，如下图：

【每日一博】Android 的三种网络通讯方式详解

在输入框里输入如下字符串，点发送按钮：

【每日一博】Android 的三种网络通讯方式详解

服务器收到客户端发来的消息并打印到控制台：

【每日一博】Android 的三种网络通讯方式详解

2、 Apache接口

对于大部分应用程序而言JDK本身提供的网络功能已远远不够，这时就需要Android提供的Apache HttpClient了。它是一个开源项目，功能更加完善，为客户端的Http编程提供高效、最新、功能丰富的工具包支持。

下面我们以一个简单例子来看看如何使用HttpClient在Android客户端访问Web。

首先，要在你的机器上搭建一个web应用test，有两个很简单的PHP文件：hello_get.php和hello_post.php！

内容如下：

hello_get.php 的代码如下：

<html>  <body>   Welcome <?php echo $_GET["name"]; ?><br>   You connected this page on : <?php echo $_GET["get"]; ?>  </body> </html>

hello_post.php的代码如下：

<html> <body> Welcome <?php echo $_POST["name"]; ?><br> You connected this page on : <?php echo $_POST["post"]; ?> </body> </html>

在原来的Android项目里新建一个Apache活动类：Apache.java，代码如下：

package com.yaowen.socketforandroid; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.view.View; import android.widget.Button; import android.widget.TextView; import org.apache.http.HttpEntity; 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.HttpGet; import org.apache.http.client.methods.HttpPost; import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.message.BasicNameValuePair; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.UnsupportedEncodingException; import java.util.ArrayList; import java.util.List; /**  * Created by YAOWEN on 2015/11/10.  */ public class ApacheActivity extends AppCompatActivity implements View.OnClickListener {  private TextView textView;  private Button get1, post1;  @Override  protected void onCreate(Bundle savedInstanceState) {   super.onCreate(savedInstanceState);   setContentView(R.layout.apache);   textView = (TextView) findViewById(R.id.textView);   get1 = (Button) findViewById(R.id.get);   post1 = (Button) findViewById(R.id.post);   get1.setOnClickListener(this);   post1.setOnClickListener(this);  }  @Override  public void onClick(View v) {   if (v.getId() == R.id.get) {    //注意：此处ip不能用127.0.0.1或localhost,Android模拟器已将它自己作为了localhost    String url = "http://192.168.3.200/test/hello_get.php?name=yaowen&get=GET";    textView.setText(get(url));   }   if (v.getId() == R.id.post) {    String url="http://192.168.3.200/test/hello_post.php";    textView.setText(post(url));   }  }  /**   * 以post方式发送请求，访问web   *   * @param url web地址   * @return 响应数据   */  private String post(String url) {   BufferedReader reader = null;   StringBuffer sb = null;   String result = "";   HttpClient client = new DefaultHttpClient();   HttpPost requset = new HttpPost(url);   //保存要传递的参数   List<NameValuePair> params = new ArrayList<NameValuePair>();   //添加参数   params.add(new BasicNameValuePair("name", "yaowen"));   params.add(new BasicNameValuePair("post","POST"));   try {    HttpEntity entity = new UrlEncodedFormEntity(params, "utf-8");    requset.setEntity(entity);    HttpResponse response = client.execute(requset);    if (response.getStatusLine().getStatusCode() == 200) {     System.out.println("post success");     reader = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));     sb = new StringBuffer();     String line = "";     String NL = System.getProperty("line.separator");     while ((line = reader.readLine()) != null) {      sb.append(line);     }    }   } catch (UnsupportedEncodingException e) {    e.printStackTrace();   } catch (ClientProtocolException e) {    e.printStackTrace();   } catch (IOException e) {    e.printStackTrace();   } finally {    if (null != reader) {     try {      reader.close();     } catch (IOException e) {      e.printStackTrace();     }    }    if (null != sb) {     result = sb.toString();    }   }   return result;  }  /**   * 以get方式发送请求，访问web   *   * @param url web地址   * @return 响应数据   */  private static String get(String url) {   BufferedReader bufferedReader = null;   StringBuffer sb = null;   String result = "";   HttpClient client = new DefaultHttpClient();   HttpGet request = new HttpGet(url);   //发送请求，得到响应   try {    HttpResponse response = client.execute(request);    //请求成功    if (response.getStatusLine().getStatusCode() == 200) {     bufferedReader = new BufferedReader(       new InputStreamReader(         response.getEntity()           .getContent()       )     );     sb = new StringBuffer();     String line = "";     String NL = System.getProperty("line.separator");     while ((line = bufferedReader.readLine()) != null) {      sb.append(line);     }    }   } catch (IOException e) {    e.printStackTrace();   } finally {    if (null != bufferedReader) {     try {      bufferedReader.close();      //bufferedReader=null;     } catch (IOException e) {      e.printStackTrace();     }    }    if (null != sb) {     result = sb.toString();    }   }   return result;  } }

新建一个apache.XML文件，如下：

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:layout_width="fill_parent"  android:layout_height="fill_parent"  android:orientation="vertical">  <TextView   android:id="@+id/textView"   android:layout_width="fill_parent"   android:layout_height="wrap_content"   android:gravity="center"   android:text="通过按钮选择不同方式访问网页" />  <Button   android:id="@+id/get"   android:layout_width="match_parent"   android:layout_height="wrap_content"   android:text="get" />  <Button   android:id="@+id/post"   android:layout_width="match_parent"   android:layout_height="wrap_content"   android:text="post" /> </LinearLayout>

结果运行如下：

【每日一博】Android 的三种网络通讯方式详解