Android文件上传

        Android实现文件的上传（并且带参数）可以使用HttpUrlConnection和HttpClient提供的一些接口，HttpClient使用比较简单一点，基本上已经封装好了可直接调用的方法，但是必须要增加几个需要的jar包。如果使用HttpUrlConnection稍微会复杂一点，以下分析第二种实现方法。

        本方法对web服务端的实现没有任何限制，主要的原理是将文件和参数信息写到输出流中，以multipart/form-data的类型将参数和文件内容分成多个部分。首先，创建一个MultiUtility的类用来封装多个部分的数据（参数和文件）：

MultiPartUtility.java

package com.yanbao.test.utils;import java.io.BufferedReader;import java.io.File;import java.io.FileInputStream;import java.io.IOException;import java.io.InputStreamReader;import java.io.OutputStream;import java.io.OutputStreamWriter;import java.io.PrintWriter;import java.net.HttpURLConnection;import java.net.URL;import java.net.URLConnection;import java.util.ArrayList;import java.util.List;public class MultipartUtility {private final String boundary;private static final String LINE_FEED = "\r\n";private HttpURLConnection httpConn;private String charset;private OutputStream outputStream;private PrintWriter writer;private static final int TIME_OUT = 10 * 1000;/** * 该构造方法初始化一个以multipart/form-data为content type的 HTTP POST 请求 *  * @param requestURL   * 请求的URL * @param charset * 字符集 * @throws IOException   */public MultipartUtility(String requestURL, String charset)throws IOException {this.charset = charset;// creates a unique boundary based on time stampboundary = "===" + System.currentTimeMillis() + "===";URL url = new URL(requestURL);httpConn = (HttpURLConnection) url.openConnection();httpConn.setConnectTimeout(TIME_OUT);httpConn.setUseCaches(false);httpConn.setDoOutput(true); // indicates POST methodhttpConn.setDoInput(true);httpConn.setRequestProperty("Content-Type","multipart/form-data; boundary=" + boundary);httpConn.setRequestProperty("User-Agent", "CodeJava Agent");httpConn.setRequestProperty("Test", "Bonjour");outputStream = httpConn.getOutputStream();writer = new PrintWriter(new OutputStreamWriter(outputStream, charset),true);}/** * 为请求添加一个表单属性 *     * @param name  * 属性名  * @param value  * 属性值  *  */public void addFormField(String name, String value) {writer.append("--" + boundary).append(LINE_FEED);writer.append("Content-Disposition: form-data; name=\"" + name + "\"").append(LINE_FEED);writer.append("Content-Type: text/plain; charset=" + charset).append(LINE_FEED);writer.append(LINE_FEED);writer.append(value).append(LINE_FEED);writer.flush();}/** * 添加上传文件部分到请求中  *  * @param fieldName * <input type="file" name="..." />中的属性名 * @param uploadFile * 待上传文件 * @throws IOException   */public void addFilePart(String fieldName, File uploadFile)throws IOException {String fileName = uploadFile.getName();writer.append("--" + boundary).append(LINE_FEED);writer.append("Content-Disposition: form-data; name=\"" + fieldName+ "\"; filename=\"" + fileName + "\"").append(LINE_FEED);writer.append("Content-Type: "+ URLConnection.guessContentTypeFromName(fileName)).append(LINE_FEED);writer.append("Content-Transfer-Encoding: binary").append(LINE_FEED);writer.append(LINE_FEED);writer.flush();FileInputStream inputStream = new FileInputStream(uploadFile);byte[] buffer = new byte[4096];int bytesRead = -1;while ((bytesRead = inputStream.read(buffer)) != -1) {outputStream.write(buffer, 0, bytesRead);}outputStream.flush();inputStream.close();writer.append(LINE_FEED);writer.flush();}/** * 向请求中添加一个头字段 *  * @param name * 头字段的名字 * @param value * 头字段的值  */public void addHeaderField(String name, String value) {writer.append(name + ": " + value).append(LINE_FEED);writer.flush();}/** * 完成请求并且接收服务器响应信息 *  * @return * 如果服务器返回状态为ok，将返回一个String的list * 否则抛出一个异常 * @throws IOException */public List<String> finish() throws IOException {List<String> response = new ArrayList<String>();writer.append(LINE_FEED).flush();writer.append("--" + boundary + "--").append(LINE_FEED);writer.close();// checks server's status code firstint status = httpConn.getResponseCode();if (status == HttpURLConnection.HTTP_OK) {BufferedReader reader = new BufferedReader(new InputStreamReader(httpConn.getInputStream()));String line = null;while ((line = reader.readLine()) != null) {response.add(line);}reader.close();httpConn.disconnect();} else {throw new IOException("Server returned non-OK status: " + status);}return response;}}

下面是一个测试的类：

UrlConnectionFileUploadTest.java

package com.yanbao.test.utils;import java.io.File;import java.io.IOException;import java.util.List;public class UrlConnectionFileUploadTest {/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubupload();}private static void upload() {// 需要请求的URLString requestURL = "https://your.request.url";String apiKey = "key123456";String fileName = "D:/logs/data-valid-api.log";String androidVersion = "4.1";String deviceName = "xiaomi";String sdkVersion = "2.1";String charset = "UTF-8";        File uploadFile = new File(fileName);         try {            MultipartUtility multipart = new MultipartUtility(requestURL, charset);                         multipart.addHeaderField("User-Agent", "Mozilla/5.0");            multipart.addHeaderField("Test-Header", "Header-Value");                         // 需要传的参数            multipart.addFormField("APIKey", apiKey);            multipart.addFormField("android_version", androidVersion);            multipart.addFormField("device_name", deviceName);            multipart.addFormField("sdk_version", sdkVersion);                         // 需要传的文件            multipart.addFilePart("file", uploadFile);             List<String> response = multipart.finish();                         System.out.println("SERVER REPLIED:");                         for (String line : response) {                System.out.println(line);            }        } catch (IOException ex) {            System.err.println(ex);        }}}

这样就可以实现带参数的post方式上传文件。