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 }
