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android网络编程

2014-02-17 14:25 197 查看

Android 网络编程---STRUTS2,JSON，HttpClient

在Android开发过程中，我们需要访问网络上的Web资源，比如网络上的WEB请求。在这里Android就好像是一个终端，可以用来接收Web服务器端发送过来的数据。下面我以Struts2作为Web服务器端的Web框架。来说明Android客户端接收Web请求的过程。

首先，我们要配置Web服务器端，添加Struts2所需要的JAR包（包括JSON包）

下面是服务器端所要配置的JAR包，如下所示：

我们看看json包，有如下： json-lib-**.jdk15.jar,struts2-json-plugin-***.jar,ezmorph-**.jar

接下配置web.xml文件，代码如下所示：

   1. 

   2.   <filter>

   3.      

   4.      <filter-name>struts2</filter-name>

   5.      

   6.      <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>

   7.   </filter>

   8.

   9.   <filter-mapping>

10.      <filter-name>struts2</filter-name>

11.      <url-pattern>/*</url-pattern>

12.   </filter-mapping>

添加完JAR包后。我们来配置一下struts.xml文件，这个文件存放在src根目录下面，代码如下所示：

   1. <?xml version="1.0" encoding="UTF-8"?>

   2. <!DOCTYPE struts PUBLIC

   3. "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"

   4. "http://struts.apache.org/dtds/struts-2.0.dtd">

   5. <struts>

   6.     

   9.     <constant name="struts.i18n.encoding" value="UTF-8"></constant>

10.     <constant name="struts.enable.DynamicMethodInvocation"

11.         value="true">

12.     </constant>

13. 

17.     

18.     <package name="dongzi" extends="json-default">

19.         

20.         <action name="login" class="com.dongzi.action.LoginAction"

21.             method="login">

22.             <result type="json"></result>

23.             

24.         </action>

25.     </package>

26. </struts>

看看这个action

    <action name="login" class="com.dongzi.action.LoginAction"

            method="login">

            <result type="json"></result>

            

        </action>

返回的是json 数据。而且是由LoginAction类去处理，它存放在com.dongzi.action下面。LoginAction类的代码如下：

   1. public class LoginAction extends ActionSupport implements ServletRequestAware,

   2.         ServletResponseAware {

   3.     /**

   4.      *

   5.      */

   6.     private static final long serialVersionUID = 1L;

   7.     HttpServletRequest request;

   8.     HttpServletResponse response;

   9.     public void setServletRequest(HttpServletRequest request) {

10.         this.request = request;

11.     }

12.     public void setServletResponse(HttpServletResponse response) {

13.         this.response = response;

14.     }

15.     public void login() {

16.         try {

17.             // HttpServletRequest request =ServletActionContext.getRequest();

18.             // HttpServletResponse response=ServletActionContext.getResponse();

19.             this.response.setContentType("text/html;charset=utf-8");

20.             this.response.setCharacterEncoding("UTF-8");

21.             // 将要返回的实体对象进行json处理

22.             // JSONObject json=JSONObject.fromObject(this.getUsername());

23.             // 输出格式如：{"id":1, "username":"zhangsan", "pwd":"123"}

24.             // System.out.println(json);

25.

26.            //   this.response.getWriter().write(json.toString());

27.

28.             //{"username":"mingg","password":"123"}

29.         JSONObject json=new JSONObject();

30. //          json.put("username", "mingg");

31. //          json.put("password","123");

32.

33.

34.

35.             //【这里在JSON中包含一个Map】

36.             Map map=new HashMap<Object, String>();

37.             map.put("username", "xiaomingg");

38.             map.put("password", "1234");

39.             map.put("state", "1");

40.             json.put("userbean", map);

41.

42.             response.getWriter().write(json.toString());

43.             ////{"userbean":{"username":"100196","password":"1234453","State":1}}

44.

45.

46.            /**

47.             * 值的数组

48.

49.             {"people": [

50.                 {"username":"mingg","password":"123","email":"172@qq.com"},

51.

52.                 {"username":"jie","password":"111","email":"172@sina.com"},

53.

54.                 {"username":"yong","password":"1232","email":"1sa@qq.com"}

55.             ]}

56.

57.             */

58.

59.

60.

61. //          JSONArray jsonArray=new JSONArray();

62. //

63. //          JSONObject json=new JSONObject();

64. //          json.put("username", "mingg");

65. //          json.put("password","123");

66. //          json.put("email", "172@qq.com");

67. //

68. //          JSONObject json1=new JSONObject();

69. //          json1.put("username", "jie");

70. //          json1.put("password","111");

71. //          json1.put("email", "172@sina.com");

72. //

73. //          JSONObject json2=new JSONObject();

74. //          json2.put("username", "yong");

75. //          json2.put("password","1232");

76. //          json2.put("email", "1sa@qq.com");

77. //

78. //          jsonArray.add(0, json);

79. //          jsonArray.add(1, json1);

80. //          jsonArray.add(2, json2);

81. //

82. //

83. //          JSONObject alObject=new JSONObject();

84. //          alObject.put("people", jsonArray);

85.

86.

87.

88.             /***

89.              *{ "programmers":      [

90.              *     {"username":"mingg","password":"123","email":"172@qq.com"},

91.              *

92.              *     {"username":"jie","password":"111","email":"172@sina.com"},

93.              *

94.              *     {"username":"yong","password":"1232","email":"1sa@qq.com"}],

95.              * "authors":    [

96.              *      {"username":"mingg","password":"123","genre":"science fiction"},

97.              *

98.              *      {"username":"jie","password":"111","genre":"fantasy"},

99.              *

100.              *      {"username":"yong","pa
d5ef
ssword":"1232","genre":"christian fiction"}],

101.              * "musicians": [

102.              *      {"username":"mingg","password":"123","instrument":"guitar"},

103.              *

104.              *      {"username":"jie","password":"111","instrument":"piano"},

105.              *

106.              *      {"username":"yong","password":"1232","instrument":"flute"}]

107.              * }

108.              *

109.              */

110.

111.

112. //          JSONArray jsonArray=new JSONArray();

113. //

114. //          JSONObject json=new JSONObject();

115. //          json.put("username", "mingg");

116. //          json.put("password","123");

117. //          json.put("email", "172@qq.com");

118. //

119. //          JSONObject json1=new JSONObject();

120. //          json1.put("username", "jie");

121. //          json1.put("password","111");

122. //          json1.put("email", "172@sina.com");

123. //

124. //          JSONObject json2=new JSONObject();

125. //          json2.put("username", "yong");

126. //          json2.put("password","1232");

127. //          json2.put("email", "1sa@qq.com");

128. //

129. //          jsonArray.add(0, json);

130. //          jsonArray.add(1, json1);

131. //          jsonArray.add(2, json2);

132. //

133. //

134. //

135. //          JSONArray jsonArray2=new JSONArray();

136. //

137. //          JSONObject json20=new JSONObject();

138. //          json20.put("username", "mingg");

139. //          json20.put("password","123");

140. //          json20.put("genre", "science fiction");

141. //

142. //          JSONObject json21=new JSONObject();

143. //          json21.put("username", "jie");

144. //          json21.put("password","111");

145. //          json21.put("genre", "fantasy");

146. //

147. //          JSONObject json22=new JSONObject();

148. //          json22.put("username", "yong");

149. //          json22.put("password","1232");

150. //          json22.put("genre", "christian fiction");

151. //

152. //          jsonArray2.add(0, json20);

153. //          jsonArray2.add(1, json21);

154. //          jsonArray2.add(2, json22);

155. //

156. //

157. //           JSONArray jsonArray3=new JSONArray();

158. //

159. //          JSONObject json30=new JSONObject();

160. //          json30.put("username", "mingg");

161. //          json30.put("password","123");

162. //          json30.put("instrument", "guitar");

163. //

164. //          JSONObject json31=new JSONObject();

165. //          json31.put("username", "jie");

166. //          json31.put("password","111");

167. //          json31.put("instrument", "piano");

168. //

169. //          JSONObject json32=new JSONObject();

170. //          json32.put("username", "yong");

171. //          json32.put("password","1232");

172. //          json32.put("instrument", "flute");//笛

173. //

174. //          jsonArray3.add(0, json30);

175. //          jsonArray3.add(1, json31);

176. //          jsonArray3.add(2, json32);

177. //

178. //

179. //          JSONObject alObject=new JSONObject();

180. //          alObject.put("programmers", jsonArray);

181. //          alObject.put("authors", jsonArray2);

182. //          alObject.put("musicians", jsonArray3);

183.

184.

185.             /**

186.              * yong:1232:1sa@qq.com

187.              */

188.             //获取任意节点的值：试例，第个节点，第三个子节点

189.

190. //          JSONArray jsonArrayt11 = (JSONArray) alObject.get("programmers");

191. //

192. //          JSONObject jsonObject11=(JSONObject)jsonArrayt11.get(2);

193. //

194. //          String username=jsonObject11.getString("username");

195. //          String password=jsonObject11.getString("password");

196. //          String email=jsonObject11.getString("email");

197. //

198. //          StringBuffer sBuffer=new StringBuffer();

199. //          sBuffer.append(username+":").append(password+":").append(email);

200.

201.

202. //          response.getWriter().write(username.toString());

203.

204.

205.

206.

207.             /**

208.              * JSONObject json=new JSONObject(); json.put("login", "login");

209.              * response.setContentType("text/html;charset=utf-8");

210.              * System.out.println(json); byte[] jsonBytes =

211.              * json.toString().getBytes("utf-8");

212.              * response.setContentLength(jsonBytes.length);

213.              * response.getOutputStream().write(jsonBytes);

214.              */

215.

216. //           JSONObject json=new JSONObject();

217. //           json.put("login", "login");

218. //            byte[] jsonBytes = json.toString().getBytes("utf-8");

219. //            response.setContentType("text/html;charset=utf-8");

220. //            response.setContentLength(jsonBytes.length);

221. //            response.getOutputStream().write(jsonBytes);

222. //            response.getOutputStream().flush();

223. //            response.getOutputStream().close();

224.

225.         } catch (Exception e) {

226.             e.printStackTrace();

227.         }

228.         // return null;

229.     }

230. }

我下面简单说一下JSON解析过程。

          JSONObject json=new JSONObject();

            //【这里在JSON中包含一个Map】

            Map map=new HashMap<Object, String>();

            map.put("username", "xiaomingg");

            map.put("password", "1234");

            map.put("state", "1");

            json.put("userbean", map);



            response.getWriter().write(json.toString());

   通过访问http://localhost:8888/AndroidServerApp/login.action，得到如下JSON数据：

服务器端的配置完成了。下面我来配置Android客户端了。

由于Android内置提拱了解析JSON数据的包。所以就不需要使用第三方包了

Android 访问网络资源的代码如下所示：

   1.     private static String url = "http://10.0.2.2:8888/AndroidServerApp/login.action";

   2. getPDAServerData(url);

   3. private void getPDAServerData(String url) {

   4.         HttpClient client = new DefaultHttpClient();

   5.         //提拱默认的HttpClient实现

   6.         HttpPost request;

   7.         try {

   8.             request = new HttpPost(new URI(url));

   9.             HttpResponse response = client.execute(request);

10.             // 判断请求是否成功

11.             if (response.getStatusLine().getStatusCode() == 200) { //200表示请求成功

12.                 HttpEntity entity = response.getEntity();

13.                 if (entity != null) {

14.                     String out = EntityUtils.toString(entity);

15.                     JSONObject jsonObject;

16.                     String username = "";

17.                     String password = "";

18.                     String stateStr="";

19.

20.                     UserBean userBean=new UserBean();

21.                     try {

22.

23.                         //{"userbean":{"username":"100196","password":"1234453","State":1}}

24.                         //JSONObject jsonObject = new JSONObject(builder.toString()).getJSONObject("userbean");

25.

26.                         jsonObject = new JSONObject(out).getJSONObject("userbean");

27.

28.

29.                         userBean.setUsername(jsonObject.getString("username"));

30.                         userBean.setPassword( jsonObject.getString("password"));

31.                         userBean.setState(Integer.parseInt(jsonObject.getString("state")));

32.

33.

34.

35.                     } catch (JSONException e) {

36.                         // TODO Auto-generated catch block

37.                         e.printStackTrace();

38.                     }

39.                     new AlertDialog.Builder(this).setMessage(

40.                             userBean.getUsername() + ":" + userBean.getState()).create().show();

41.                 }

42.             }

43.         } catch (URISyntaxException e) {

44.             e.printStackTrace();

45.             new AlertDialog.Builder(this).setMessage(e.getMessage()).create()

46.                     .show();

47.         } catch (ClientProtocolException e) {

48.             e.printStackTrace();

49.             new AlertDialog.Builder(this).setMessage(e.getMessage()).create()

50.                     .show();

51.         } catch (IOException e) {

52.             e.printStackTrace();

53.             new AlertDialog.Builder(this).setMessage(e.getMessage()).create()

54.                     .show();

55.         }

56.     }

里面的IP地址：10.0.2.2，代表着手机模拟器本地的地址，相当于localhost,但不能使用localhost,或者127.0.0.1，因不是在PC机上测试，而是在手机AVD上测试之。

而UserBean.java,它就是一个JAVABEAN,代码如下所示：

   1. package po;

   2. public class UserBean {

   3.     private String username;

   4.     private String password;

   5.     private int state;

   6.     public String getUsername() {

   7.         return username;

   8.     }

   9.     public void setUsername(String username) {

10.         this.username = username;

11.     }

12.     public String getPassword() {

13.         return password;

14.     }

15.     public void setPassword(String password) {

16.         this.password = password;

17.     }

18.     public int getState() {

19.         return state;

20.     }

21.     public void setState(int state) {

22.         this.state = state;

23.     }

24. }

注恴必须AndroidManifest.xml中加入如下代码，不然Android就不能访问web资源。

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

转自http://www.linuxidc.com/Linux/2011-04/35009.htm

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