Android的三种网络通信方式

小鱼儿 2022-08-19 14:28 154阅读 0赞

Android平台有三种网络接口可以使用，他们分别是：java.net.\*(标准Java接口)、Org.apache接口和Android.net.\*(Android网络接口)。下面分别介绍这些接口的功能和作用。  
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。  
服务端：

**\[java\]** [ view plain][view plain] [copy][view plain]

1.  public class Server implements Runnable\{
2.  @Override
3.  public void run() \{
4.  Socket socket = null;
5.  try \{
6.  ServerSocket server = new ServerSocket(18888);
7.  //循环监听客户端链接请求
8.  while(true)\{
9.  System.out.println("start...");
10. //接收请求
11. socket = server.accept();
12. System.out.println("accept...");
13. //接收客户端消息
14. BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
15. String message = in.readLine();
16. //发送消息，向客户端
17. PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())),true);
18. out.println("Server:" \+ message);
19. //关闭流
20. in.close();
21. out.close();
22. \}
23. \} catch (IOException e) \{
24. e.printStackTrace();
25. \}finally\{
26. if (null != socket)\{
27. try \{
28. socket.close();
29. \} catch (IOException e) \{
30. e.printStackTrace();
31. \}
32. \}
33. \}
34. 
35. \}
36. //启动服务器
37. public static void main(String\[\] args)\{
38. Thread server = new Thread(new Server());
39. server.start();
40. \}
41. \}

客户端，MainActivity

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1.  public class MainActivity extends Activity \{
2.  private EditText editText;
3.  private Button button;
4.  /\*\* Called when the activity is first created. \*/
5.  @Override
6.  public void onCreate(Bundle savedInstanceState) \{
7.  super.onCreate(savedInstanceState);
8.  setContentView(R.layout.main);
9.  
10. editText = (EditText)findViewById(R.id.editText1);
11. button = (Button)findViewById(R.id.button1);
12. 
13. button.setOnClickListener(new OnClickListener() \{
14. @Override
15. public void onClick(View v) \{
16. Socket socket = null;
17. String message = editText.getText().toString()+ "\\r\\n" ;
18. try \{
19. //创建客户端socket,注意:不能用localhost或127.0.0.1，Android模拟器把自己作为localhost
20. socket = new Socket("<span style="font-weight: bold;">10.0.2.2</span>",18888);
21. PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter
22. (socket.getOutputStream())),true);
23. //发送数据
24. out.println(message);
25. 
26. //接收数据
27. BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
28. String msg = in.readLine();
29. if (null != msg)\{
30. editText.setText(msg);
31. System.out.println(msg);
32. \}
33. else\{
34. editText.setText("data error");
35. \}
36. out.close();
37. in.close();
38. \} catch (UnknownHostException e) \{
39. e.printStackTrace();
40. \} catch (IOException e) \{
41. e.printStackTrace();
42. \}
43. finally\{
44. try \{
45. if (null != socket)\{
46. socket.close();
47. \}
48. \} catch (IOException e) \{
49. e.printStackTrace();
50. \}
51. \}
52. \}
53. \});
54. \}
55. \}

布局文件：

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1.  <?xml version="1.0" encoding="utf-8"?>
2.  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
3.  android:orientation="vertical" android:layout\_width="fill\_parent"
4.  android:layout\_height="fill\_parent">
5.  <TextView android:layout\_width="fill\_parent"
6.  android:layout\_height="wrap\_content" android:text="@string/hello" />
7.  <EditText android:layout\_width="match\_parent" android:id="@+id/editText1"
8.  android:layout\_height="wrap\_content"
9.  android:hint="input the message and click the send button"
10. ></EditText>
11. <Button android:text="send" android:id="@+id/button1"
12. android:layout\_width="fill\_parent" android:layout\_height="wrap\_content"></Button>
13. </LinearLayout>

启动服务器：

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1.  javac com/test/socket/Server.java
2.  java com.test.socket.Server

运行客户端程序：

结果如图：

![1336648682_2648.png][]

![1336648708_3729.png][]

注意：服务器与客户端无法链接的可能原因有：  
没有加访问网络的权限：<uses-permission android:name="android.permission.INTERNET"></uses-permission>  
IP地址要使用：10.0.2.2  
模拟器不能配置代理。  
  
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myapp，只有很简单的一个http.jsp  
内容如下：

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1.  <%@page language="java" import="java.util.\*" pageEncoding="utf-8"%>
2.  <html>
3.  <head>
4.  <title>
5.  Http Test
6.  </title>
7.  </head>
8.  <body>
9.  <%
10. String type = request.getParameter("parameter");
11. String result = new String(type.getBytes("iso-8859-1"),"utf-8");
12. out.println("<h1>" \+ result + "</h1>");
13. %>
14. </body>
15. </html>

然后实现Android客户端，分别以post、get方式去访问myapp,代码如下：  
布局文件：

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1.  <?xml version="1.0" encoding="utf-8"?>
2.  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
3.  android:orientation="vertical"
4.  android:layout\_width="fill\_parent"
5.  android:layout\_height="fill\_parent"
6.  >
7.  <TextView
8.  android:gravity="center"
9.  android:id="@+id/textView"
10. android:layout\_width="fill\_parent"
11. android:layout\_height="wrap\_content"
12. android:text="@string/hello"
13. />
14. <Button android:text="get" android:id="@+id/get" android:layout\_width="match\_parent" android:layout\_height="wrap\_content"></Button>
15. <Button android:text="post" android:id="@+id/post" android:layout\_width="match\_parent" android:layout\_height="wrap\_content"></Button>
16. </LinearLayout>

资源文件：  
strings.xml

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1.  <?xml version="1.0" encoding="utf-8"?>
2.  <resources>
3.  <string name="hello">通过按钮选择不同方式访问网页</string>
4.  <string name="app\_name">Http Get</string>
5.  </resources>

主Activity:

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1.  public class MainActivity extends Activity \{
2.  private TextView textView;
3.  private Button get,post;
4.  /\*\* Called when the activity is first created. \*/
5.  @Override
6.  public void onCreate(Bundle savedInstanceState) \{
7.  super.onCreate(savedInstanceState);
8.  setContentView(R.layout.main);
9.  
10. textView = (TextView)findViewById(R.id.textView);
11. get = (Button)findViewById(R.id.get);
12. post = (Button)findViewById(R.id.post);
13. 
14. //绑定按钮监听器
15. get.setOnClickListener(new OnClickListener() \{
16. @Override
17. public void onClick(View v) \{
18. //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
19. String uri = "http://192.168.22.28:8080/myapp/http.jsp?parameter=以Get方式发送请求";
20. textView.setText(get(uri));
21. \}
22. \});
23. //绑定按钮监听器
24. post.setOnClickListener(new OnClickListener() \{
25. @Override
26. public void onClick(View v) \{
27. String uri = "http://192.168.22.28:8080/myapp/http.jsp";
28. textView.setText(post(uri));
29. \}
30. \});
31. \}
32. /\*\*
33.  \* 以get方式发送请求，访问web
34.  \* @param uri web地址
35.  \* @return 响应数据
36.  \*/
37. private static String get(String uri)\{
38. BufferedReader reader = null;
39. StringBuffer sb = null;
40. String result = "";
41. HttpClient client = new DefaultHttpClient();
42. HttpGet request = new HttpGet(uri);
43. try \{
44. //发送请求，得到响应
45. HttpResponse response = client.execute(request);
46. 
47. //请求成功
48. if (response.getStatusLine().getStatusCode() == HttpStatus.SC\_OK)\{
49. reader = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
50. sb = new StringBuffer();
51. String line = "";
52. String NL = System.getProperty("line.separator");
53. while((line = reader.readLine()) != null)\{
54. sb.append(line);
55. \}
56. \}
57. \} catch (ClientProtocolException e) \{
58. e.printStackTrace();
59. \} catch (IOException e) \{
60. e.printStackTrace();
61. \}
62. finally\{
63. try \{
64. if (null != reader)\{
65. reader.close();
66. reader = null;
67. \}
68. \} catch (IOException e) \{
69. e.printStackTrace();
70. \}
71. \}
72. if (null != sb)\{
73. result = sb.toString();
74. \}
75. return result;
76. \}
77. /\*\*
78.  \* 以post方式发送请求，访问web
79.  \* @param uri web地址
80.  \* @return 响应数据
81.  \*/
82. private static String post(String uri)\{
83. BufferedReader reader = null;
84. StringBuffer sb = null;
85. String result = "";
86. HttpClient client = new DefaultHttpClient();
87. HttpPost request = new HttpPost(uri);
88. 
89. //保存要传递的参数
90. List<NameValuePair> params = new ArrayList<NameValuePair>();
91. //添加参数
92. params.add(new BasicNameValuePair("parameter","以Post方式发送请求"));
93. 
94. try \{
95. //设置字符集
96. HttpEntity entity = new UrlEncodedFormEntity(params,"utf-8");
97. //请求对象
98. request.setEntity(entity);
99. //发送请求
100. HttpResponse response = client.execute(request);
101. 
102. //请求成功
103. if (response.getStatusLine().getStatusCode() == HttpStatus.SC\_OK)\{
104. System.out.println("post success");
105. reader = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
106. sb = new StringBuffer();
107. String line = "";
108. String NL = System.getProperty("line.separator");
109. while((line = reader.readLine()) != null)\{
110. sb.append(line);
111. \}
112. \}
113. \} catch (ClientProtocolException e) \{
114. e.printStackTrace();
115. \} catch (IOException e) \{
116. e.printStackTrace();
117. \}
118. finally\{
119. try \{
120. //关闭流
121. if (null != reader)\{
122. reader.close();
123. reader = null;
124. \}
125. \} catch (IOException e) \{
126. e.printStackTrace();
127. \}
128. \}
129. if (null != sb)\{
130. result = sb.toString();
131. \}
132. return result;
133. \}
134. \}

运行结果如下：

![1336648801_2776.png][]

![1336648820_1021.png][]

3.android.net编程：  
常常使用此包下的类进行Android特有的网络编程，如：访问WiFi，访问Android联网信息，邮件等功能。这里不详细讲。

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[1336648682_2648.png]: https://img-my.csdn.net/uploads/201205/10/1336648682_2648.png
[1336648708_3729.png]: https://img-my.csdn.net/uploads/201205/10/1336648708_3729.png
[1336648801_2776.png]: https://img-my.csdn.net/uploads/201205/10/1336648801_2776.png
[1336648820_1021.png]: https://img-my.csdn.net/uploads/201205/10/1336648820_1021.png