http://blog.csdn.net/furongkang/article/details/6838450
Android上传文件有两种方式，第一种是基于Http协议的HttpURLConnection，第二种是基于TCP协议的Socket。 这两种方式的区别是使用HttpURLConnection上传时内部有缓存机制，如果上传较大文件会导致内存溢出。如果用TCP协议Socket方式上传就会解决这种弊端。
HTTP协议HttpURLConnection
1. 通过URL封装路径打开一个HttpURLConnection
2.设置请求方式以及头字段：Content-Type、Content-Length、Host
3.拼接数据发送
示例：
- private static final String BOUNDARY = "---------------------------7db1c523809b2";//数据分割线
- public boolean uploadHttpURLConnection(String username, String password, String path) throws Exception {
- //找到sdcard上的文件
- File file = new File(Environment.getExternalStorageDirectory(), path);
- //仿Http协议发送数据方式进行拼接
- StringBuilder sb = new StringBuilder();
- sb.append("--" + BOUNDARY + "\r\n");
- sb.append("Content-Disposition: form-data; name=\"username\"" + "\r\n");
- sb.append("\r\n");
- sb.append(username + "\r\n");
- sb.append("--" + BOUNDARY + "\r\n");
- sb.append("Content-Disposition: form-data; name=\"password\"" + "\r\n");
- sb.append("\r\n");
- sb.append(password + "\r\n");
- sb.append("--" + BOUNDARY + "\r\n");
- sb.append("Content-Disposition: form-data; name=\"file\"; filename=\"" + path + "\"" + "\r\n");
- sb.append("Content-Type: image/pjpeg" + "\r\n");
- sb.append("\r\n");
- byte[] before = sb.toString().getBytes("UTF-8");
- byte[] after = ("\r\n--" + BOUNDARY + "--\r\n").getBytes("UTF-8");
- URL url = new URL("http://192.168.1.16:8080/14_Web/servlet/LoginServlet");
- HttpURLConnection conn = (HttpURLConnection) url.openConnection();
- conn.setRequestMethod("POST");
- conn.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + BOUNDARY);
- conn.setRequestProperty("Content-Length", String.valueOf(before.length + file.length() + after.length));
- conn.setRequestProperty("HOST", "192.168.1.16:8080");
- conn.setDoOutput(true);
- OutputStream out = conn.getOutputStream();
- InputStream in = new FileInputStream(file);
- out.write(before);
- byte[] buf = new byte[1024];
- int len;
- while ((len = in.read(buf)) != -1)
- out.write(buf, 0, len);
- out.write(after);
- in.close();
- out.close();
- return conn.getResponseCode() == 200;
- }
TCP协议Socket
1.我们可以使用Socket发送TCP请求，将上传数据分段发送
示例：
- public boolean uploadBySocket(String username, String password, String path) throws Exception {
- // 根据path找到SDCard中的文件
- File file = new File(Environment.getExternalStorageDirectory(), path);
- // 组装表单字段和文件之前的数据
- StringBuilder sb = new StringBuilder();
- sb.append("--" + BOUNDARY + "\r\n");
- sb.append("Content-Disposition: form-data; name=\"username\"" + "\r\n");
- sb.append("\r\n");
- sb.append(username + "\r\n");
- sb.append("--" + BOUNDARY + "\r\n");
- sb.append("Content-Disposition: form-data; name=\"password\"" + "\r\n");
- sb.append("\r\n");
- sb.append(password + "\r\n");
- sb.append("--" + BOUNDARY + "\r\n");
- sb.append("Content-Disposition: form-data; name=\"file\"; filename=\"" + path + "\"" + "\r\n");
- sb.append("Content-Type: image/pjpeg" + "\r\n");
- sb.append("\r\n");
- // 文件之前的数据
- byte[] before = sb.toString().getBytes("UTF-8");
- // 文件之后的数据
- byte[] after = ("\r\n--" + BOUNDARY + "--\r\n").getBytes("UTF-8");
- URL url = new URL("http://192.168.1.199:8080/14_Web/servlet/LoginServlet");
- // 由于HttpURLConnection中会缓存数据, 上传较大文件时会导致内存溢出, 所以我们使用Socket传输
- Socket socket = new Socket(url.getHost(), url.getPort());
- OutputStream out = socket.getOutputStream();
- PrintStream ps = new PrintStream(out, true, "UTF-8");
- // 写出请求头
- ps.println("POST /14_Web/servlet/LoginServlet HTTP/1.1");
- ps.println("Content-Type: multipart/form-data; boundary=" + BOUNDARY);
- ps.println("Content-Length: " + String.valueOf(before.length + file.length() + after.length));
- ps.println("Host: 192.168.1.199:8080");
- InputStream in = new FileInputStream(file);
- // 写出数据
- out.write(before);
- byte[] buf = new byte[1024];
- int len;
- while ((len = in.read(buf)) != -1)
- out.write(buf, 0, len);
- out.write(after);
- in.close();
- out.close();
- return true;
- }
搭建服务器，完成上传功能
- package cn.test.web.servlet;
- import java.io.File;
- import java.io.IOException;
- import java.util.List;
- import javax.servlet.ServletException;
- import javax.servlet.http.HttpServlet;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
- import org.apache.commons.fileupload.FileItem;
- import org.apache.commons.fileupload.FileItemFactory;
- import org.apache.commons.fileupload.disk.DiskFileItemFactory;
- import org.apache.commons.fileupload.servlet.ServletFileUpload;
- public class LoginServlet extends HttpServlet {
- private static final long serialVersionUID = 1L;
- @Override
- public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
- doPost(request, response);
- }
- @Override
- public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
- boolean isMultipart = ServletFileUpload.isMultipartContent(request);
- if (isMultipart)
- try {
- FileItemFactory factory = new DiskFileItemFactory();
- ServletFileUpload upload = new ServletFileUpload(factory);
- List<FileItem> items = upload.parseRequest(request);
- File dir = new File(request.getSession().getServletContext().getRealPath("/WEB-INF/upload"));
- //创建目录
- dir.mkdir();
- for (FileItem item : items)
- if (item.isFormField())
- System.out.println(item.getFieldName() + ": " + item.getString());
- else{
- item.write(new File(dir,item.getName().substring(item.getName().lastIndexOf("\\")+1)));
- }
- } catch (Exception e) {
- e.printStackTrace();
- }
- else {
- System.out.println(request.getMethod());
- System.out.println(request.getParameter("username"));
- System.out.println(request.getParameter("password"));
- }
- }
- }
