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：
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
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：
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：
1 javac com/test/socket/Server.java 2 java com.test.socket.Server
运行客户端程序：
结果如图：
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：
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：
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
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:
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：
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。
参考原文：http://blog.csdn.net/yuzhiboyi/article/details/7743390
时间： 2024-08-11 16:40:00