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";
-
-
public boolean uploadHttpURLConnection(String username, String password, String path) throws Exception {
-
-
File file = new File(Environment.getExternalStorageDirectory(), path);
-
-
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 {
-
-
File file = new File(Environment.getExternalStorageDirectory(), path);
-
-
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://192.168.1.199:8080/14_Web/servlet/LoginServlet");
-
-
-
Socket socket = new Socket(url.getHost(), url.getPort());
-
OutputStream out = socket.getOutputStream();
-
PrintStream ps = new PrintStream(out, true, "UTF-8");
-
-
-
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);
-
-
-
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"));
-
-
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"));
-
}
-
}
-
}