您的位置:首页 > 理论基础 > 计算机网络

Android分别使用HTTP协议和TCP协议实现上传文件

2013-03-06 10:06 731 查看
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:

[java] view
plaincopy

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:

[java] view
plaincopy

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

[java] view
plaincopy

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"));

}

}

}
内容来自用户分享和网络整理,不保证内容的准确性,如有侵权内容,可联系管理员处理 点击这里给我发消息
标签: