Android 网络编程（一）

概述

一。Android平台网络相关API接口

　　1.java.net.*(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。

　　

　　2.org.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。

　　3.Android.net.*(Android网络接口)

　　　　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。

二。服务器端返回客户端的内容有三种方式

　　

　　1.以HTML代码的形式返回。

　　2.以XML字符串的形式返回，做Android开发时这种方式比较多。返回的数据需要通过XML解析（SAX、DOM，Pull,等）器进行解析（必备知识）。

　　3.以json对象的方式返回。

 

封装的工具类

•    发送GET请求；
•    发送POST请求；
•    发送文件上传请求；
• 　发送XML数据；

  1 package com.kest.util;
  2 
  3 import java.io.BufferedReader;
  4 import java.io.ByteArrayOutputStream;
  5 import java.io.InputStream;
  6 import java.io.InputStreamReader;
  7 import java.io.OutputStream;
  8 import java.net.HttpURLConnection;
  9 import java.net.InetAddress;
 10 import java.net.Socket;
 11 import java.net.URL;
 12 import java.net.URLConnection;
 13 import java.net.URLEncoder;
 14 import java.util.Map;
 15 
 16 /**
 17  * 
 18  *
 19  *         (1)发送GET请求；
 20  * 
 21  *         (2)发送POST请求；
 22  * 
 23  *         (3)发送文件上传请求；
 24  * 
 25  *         (4)发送XML数据；
 26  */
 27 
 28 public class HttpRequestUtil {
 29     /**
 30      * 发送GET请求
 31      * 
 32      * @param url
 33      * @param params
 34      * @param headers
 35      * @return URLConnection
 36      * @throws Exception
 37      */
 38     public static URLConnection sendGetRequest(String url,
 39             Map<String, String> params, Map<String, String> headers)
 40             throws Exception {
 41         StringBuilder sb = new StringBuilder(url);
 42         // 如果是GET请求，则请求参数在URL中
 43         if (params != null && !params.isEmpty()) {
 44             sb.append("?");
 45             for (Map.Entry<String, String> entry : params.entrySet()) {
 46                 sb.append(entry.getKey()).append("=")
 47                         .append(URLEncoder.encode(entry.getValue(), "UTF-8"))
 48                         .append("&");
 49             }
 50             sb.deleteCharAt(sb.length() - 1);
 51         }
 52         URL url1 = new URL(sb.toString());
 53         HttpURLConnection conn = (HttpURLConnection) url1.openConnection();
 54         conn.setRequestMethod("GET");
 55         // 设置请求头
 56         if (headers != null && !headers.isEmpty()) {
 57             for (Map.Entry<String, String> entry : headers.entrySet()) {
 58                 conn.setRequestProperty(entry.getKey(), entry.getValue());
 59             }
 60         }
 61         conn.getResponseCode();
 62         return conn;
 63     }
 64 
 65     /**
 66      * 发送POST请求
 67      * 
 68      * @param url
 69      * @param params
 70      * @param headers
 71      * @return URLConnection
 72      * @throws Exception
 73      */
 74     public static URLConnection sendPostRequest(String url,
 75             Map<String, String> params, Map<String, String> headers)
 76             throws Exception {
 77         StringBuilder sb = new StringBuilder();
 78         // 如果存在参数，则放在HTTP请求体，形如name=aaa&age=10
 79         if (params != null && !params.isEmpty()) {
 80             for (Map.Entry<String, String> entry : params.entrySet()) {
 81                 sb.append(entry.getKey()).append("=")
 82                         .append(URLEncoder.encode(entry.getValue(), "UTF-8"))
 83                         .append("&");
 84             }
 85             sb.deleteCharAt(sb.length() - 1);
 86         }
 87         URL url1 = new URL(url);
 88         HttpURLConnection conn = (HttpURLConnection) url1.openConnection();
 89         conn.setRequestMethod("POST");
 90         conn.setDoOutput(true);
 91         OutputStream out = conn.getOutputStream();
 92         out.write(sb.toString().getBytes("UTF-8"));
 93         if (headers != null && !headers.isEmpty()) {
 94             for (Map.Entry<String, String> entry : headers.entrySet()) {
 95                 conn.setRequestProperty(entry.getKey(), entry.getValue());
 96             }
 97         }
 98         conn.getResponseCode(); // 为了发送成功
 99         return conn;
100     }
101 
102     /**
103      * 直接通过HTTP协议提交数据到服务器,实现如下面表单提交功能: <FORM METHOD=POST
104      * ACTION="http://192.168.0.200:8080/ssi/fileload/test.do"
105      * enctype="multipart/form-data"> <INPUT TYPE="text" NAME="name"> <INPUT
106      * TYPE="text" NAME="id"> <input type="file" name="imagefile"/> <input
107      * type="file" name="zip"/> </FORM>
108      * 
109      * @param path
110      *            
111      * @param params
112      *            请求参数 key为参数名,value为参数值
113      * @param file
114      *            上传文件
115      */
116     public static boolean uploadFiles(String path, Map<String, String> params,
117             FormFile[] files) throws Exception {
118         final String BOUNDARY = "---------------------------7da2137580612"; // 数据分隔线
119         final String endline = "--" + BOUNDARY + "--\r\n";// 数据结束标志
120 
121         int fileDataLength = 0;
122         if (files != null && files.length != 0) {
123             for (FormFile uploadFile : files) {// 得到文件类型数据的总长度
124                 StringBuilder fileExplain = new StringBuilder();
125                 fileExplain.append("--");
126                 fileExplain.append(BOUNDARY);
127                 fileExplain.append("\r\n");
128                 fileExplain.append("Content-Disposition: form-data;name=\""
129                         + uploadFile.getParameterName() + "\";filename=\""
130                         + uploadFile.getFilname() + "\"\r\n");
131                 fileExplain.append("Content-Type: "
132                         + uploadFile.getContentType() + "\r\n\r\n");
133                 fileExplain.append("\r\n");
134                 fileDataLength += fileExplain.length();
135                 if (uploadFile.getInStream() != null) {
136                     fileDataLength += uploadFile.getFile().length();
137                 } else {
138                     fileDataLength += uploadFile.getData().length;
139                 }
140             }
141         }
142         StringBuilder textEntity = new StringBuilder();
143         if (params != null && !params.isEmpty()) {
144             for (Map.Entry<String, String> entry : params.entrySet()) {// 构造文本类型参数的实体数据
145                 textEntity.append("--");
146                 textEntity.append(BOUNDARY);
147                 textEntity.append("\r\n");
148                 textEntity.append("Content-Disposition: form-data; name=\""
149                         + entry.getKey() + "\"\r\n\r\n");
150                 textEntity.append(entry.getValue());
151                 textEntity.append("\r\n");
152             }
153         }
154         // 计算传输给服务器的实体数据总长度
155         int dataLength = textEntity.toString().getBytes().length
156                 + fileDataLength + endline.getBytes().length;
157 
158         URL url = new URL(path);
159         int port = url.getPort() == -1 ? 80 : url.getPort();
160         Socket socket = new Socket(InetAddress.getByName(url.getHost()), port);
161         OutputStream outStream = socket.getOutputStream();
162         // 下面完成HTTP请求头的发送
163         String requestmethod = "POST " + url.getPath() + " HTTP/1.1\r\n";
164         outStream.write(requestmethod.getBytes());
165         String accept = "Accept: image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-shockwave-flash, application/xaml+xml, application/vnd.ms-xpsdocument, application/x-ms-xbap, application/x-ms-application, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*\r\n";
166         outStream.write(accept.getBytes());
167         String language = "Accept-Language: zh-CN\r\n";
168         outStream.write(language.getBytes());
169         String contenttype = "Content-Type: multipart/form-data; boundary="
170                 + BOUNDARY + "\r\n";
171         outStream.write(contenttype.getBytes());
172         String contentlength = "Content-Length: " + dataLength + "\r\n";
173         outStream.write(contentlength.getBytes());
174         String alive = "Connection: Keep-Alive\r\n";
175         outStream.write(alive.getBytes());
176         String host = "Host: " + url.getHost() + ":" + port + "\r\n";
177         outStream.write(host.getBytes());
178         // 写完HTTP请求头后根据HTTP协议再写一个回车换行
179         outStream.write("\r\n".getBytes());
180         // 把所有文本类型的实体数据发送出来
181         outStream.write(textEntity.toString().getBytes());
182         // 把所有文件类型的实体数据发送出来
183         if (files != null && files.length != 0) {
184             for (FormFile uploadFile : files) {
185                 StringBuilder fileEntity = new StringBuilder();
186                 fileEntity.append("--");
187                 fileEntity.append(BOUNDARY);
188                 fileEntity.append("\r\n");
189                 fileEntity.append("Content-Disposition: form-data;name=\""
190                         + uploadFile.getParameterName() + "\";filename=\""
191                         + uploadFile.getFilname() + "\"\r\n");
192                 fileEntity.append("Content-Type: "
193                         + uploadFile.getContentType() + "\r\n\r\n");
194                 outStream.write(fileEntity.toString().getBytes());
195                 if (uploadFile.getInStream() != null) {
196                     byte[] buffer = new byte[1024];
197                     int len = 0;
198                     while ((len = uploadFile.getInStream()
199                             .read(buffer, 0, 1024)) != -1) {
200                         outStream.write(buffer, 0, len);
201                     }
202                     uploadFile.getInStream().close();
203                 } else {
204                     outStream.write(uploadFile.getData(), 0,
205                             uploadFile.getData().length);
206                 }
207                 outStream.write("\r\n".getBytes());
208             }
209         }
210         // 下面发送数据结束标志，表示数据已经结束
211         outStream.write(endline.getBytes());
212         BufferedReader reader = new BufferedReader(new InputStreamReader(
213                 socket.getInputStream()));
214         if (reader.readLine().indexOf("200") == -1) {// 读取web服务器返回的数据，判断请求码是否为200，如果不是200，代表请求失败
215             return false;
216         }
217         outStream.flush();
218         outStream.close();
219         reader.close();
220         socket.close();
221         return true;
222     }
223 
224     /**
225      * 提交数据到服务器
226      * 
227      * @param path
228      *            
229      * @param params
230      *            请求参数 key为参数名,value为参数值
231      * @param file
232      *            上传文件
233      */
234     public static boolean uploadFile(String path, Map<String, String> params,
235             FormFile file) throws Exception {
236         return uploadFiles(path, params, new FormFile[] { file });
237     }
238 
239     /**
240      * 将输入流转为字节数组
241      * 
242      * @param inStream
243      * @return
244      * @throws Exception
245      */
246     public static byte[] read2Byte(InputStream inStream) throws Exception {
247         ByteArrayOutputStream outSteam = new ByteArrayOutputStream();
248         byte[] buffer = new byte[1024];
249         int len = 0;
250         while ((len = inStream.read(buffer)) != -1) {
251             outSteam.write(buffer, 0, len);
252         }
253         outSteam.close();
254         inStream.close();
255         return outSteam.toByteArray();
256     }
257 
258     /**
259      * 将输入流转为字符串
260      * 
261      * @param inStream
262      * @return
263      * @throws Exception
264      */
265     public static String read2String(InputStream inStream) throws Exception {
266         ByteArrayOutputStream outSteam = new ByteArrayOutputStream();
267         byte[] buffer = new byte[1024];
268         int len = 0;
269         while ((len = inStream.read(buffer)) != -1) {
270             outSteam.write(buffer, 0, len);
271         }
272         outSteam.close();
273         inStream.close();
274         return new String(outSteam.toByteArray(), "UTF-8");
275     }
276 
277     /**
278      * 发送xml数据
279      * 
280      * @param path
281      *            请求地址
282      * @param xml
283      *            xml数据
284      * @param encoding
285      *            编码
286      * @return
287      * @throws Exception
288      */
289     public static byte[] postXml(String path, String xml, String encoding)
290             throws Exception {
291         byte[] data = xml.getBytes(encoding);
292         URL url = new URL(path);
293         HttpURLConnection conn = (HttpURLConnection) url.openConnection();
294         conn.setRequestMethod("POST");
295         conn.setDoOutput(true);
296         conn.setRequestProperty("Content-Type", "text/xml; charset=" + encoding);
297         conn.setRequestProperty("Content-Length", String.valueOf(data.length));
298         conn.setConnectTimeout(5 * 1000);
299         OutputStream outStream = conn.getOutputStream();
300         outStream.write(data);
301         outStream.flush();
302         outStream.close();
303         if (conn.getResponseCode() == 200) {
304             return read2Byte(conn.getInputStream());
305         }
306         return null;
307     }
308 }