Android上傳文件有兩種方式,第一種是基於Http協議的HttpURLConnection,第二種是基於TCP協議的Socket。 這兩種方式的區別是使用HttpURLConnection上傳時內部有緩存機制,如果上傳較大文件會導致內存溢出。如果用TCP協議Socket方式上傳就會解決這種弊端。
HTTP協議HttpURLConnection
1. 通過URL封裝路徑打開一個HttpURLConnection
2.設置請求方式以及頭字段:Content-Type、Content-Length、Host
3.拼接數據發送
示例:
- private static final String BOUNDARY = "---------------------------7db1c523809b2";//數據分割線
-
- 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協議發送數據方式進行拼接
- 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協議Socket
1.我們可以使用Socket發送TCP請求,將上傳數據分段發送
示例:
- public boolean uploadBySocket(String username, String password, String path) throws Exception {
- // 根據path找到SDCard中的文件
- File file = new File(Environment.getExternalStorageDirectory(), path);
- // 組裝表單字段和文件之前的數據
- 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");
-
- // 文件之前的數據
- byte[] before = sb.toString().getBytes("UTF-8");
- // 文件之後的數據
- byte[] after = ("\r\n--" + BOUNDARY + "--\r\n").getBytes("UTF-8");
-
- URL url = new URL("http://192.168.1.199:8080/14_Web/servlet/LoginServlet");
-
- // 由於HttpURLConnection中會緩存數據, 上傳較大文件時會導致內存溢出, 所以我們使用Socket傳輸
- Socket socket = new Socket(url.getHost(), url.getPort());
- OutputStream out = socket.getOutputStream();
- PrintStream ps = new PrintStream(out, true, "UTF-8");
-
- // 寫出請求頭
- 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);
-
- // 寫出數據
- 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;
- }