基于http或TCP实现文件上传科卓培训

Android上传文件有两种方式&＃xff0c;第一种是基于Http协议的HttpURLConnection&＃xff0c;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&＃xff0c;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&＃xff1a;Content-Type、Content-Length、Host

3.拼接数据发送

示例&＃xff1a;

private static final String BOUNDARY &＃61; "---------------------------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 &＃61; new File(Environment.getExternalStorageDirectory(), path);  
                 //仿Http协议发送数据方式进行拼接  
    StringBuilder sb &＃61; new StringBuilder();  
    sb.append("--" &＃43; BOUNDARY &＃43; "\r\n");  
    sb.append("Content-Disposition: form-data; name&＃61;\"username\"" &＃43; "\r\n");  
    sb.append("\r\n");  
    sb.append(username &＃43; "\r\n");  
  
    sb.append("--" &＃43; BOUNDARY &＃43; "\r\n");  
    sb.append("Content-Disposition: form-data; name&＃61;\"password\"" &＃43; "\r\n");  
    sb.append("\r\n");  
    sb.append(password &＃43; "\r\n");  
  
    sb.append("--" &＃43; BOUNDARY &＃43; "\r\n");  
    sb.append("Content-Disposition: form-data; name&＃61;\"file\"; filename&＃61;\"" &＃43; path &＃43; "\"" &＃43; "\r\n");  
    sb.append("Content-Type: image/pjpeg" &＃43; "\r\n");  
    sb.append("\r\n");  
  
    byte[] before &＃61; sb.toString().getBytes("UTF-8");  
    byte[] after &＃61; ("\r\n--" &＃43; BOUNDARY &＃43; "--\r\n").getBytes("UTF-8");  
  
    URL url &＃61; new URL("http://192.168.1.16:8080/14_Web/servlet/LoginServlet");  
    HttpURLConnection conn &＃61; (HttpURLConnection) url.openConnection();  
    conn.setRequestMethod("POST");  
    conn.setRequestProperty("Content-Type", "multipart/form-data; boundary&＃61;" &＃43; BOUNDARY);  
    conn.setRequestProperty("Content-Length", String.valueOf(before.length &＃43; file.length() &＃43; after.length));  
    conn.setRequestProperty("HOST", "192.168.1.16:8080");  
    conn.setDoOutput(true);   
  
    OutputStream out &＃61; conn.getOutputStream();  
    InputStream in &＃61; new FileInputStream(file);  
      
    out.write(before);  
  
    byte[] buf &＃61; new byte[1024];  
    int len;  
    while ((len &＃61; in.read(buf)) !&＃61; -1)  
        out.write(buf, 0, len);  
  
    out.write(after);  
  
    in.close();  
    out.close();  
    return conn.getResponseCode() &＃61;&＃61; 200;  
}
TCP协议Socket

1.我们可以使用Socket发送TCP请求&＃xff0c;将上传数据分段发送

示例&＃xff1a;

public boolean uploadBySocket(String username, String password, String path) throws Exception {  
    // 根据path找到SDCard中的文件  
    File file &＃61; new File(Environment.getExternalStorageDirectory(), path);  
    // 组装表单字段和文件之前的数据  
    StringBuilder sb &＃61; new StringBuilder();  
  
    sb.append("--" &＃43; BOUNDARY &＃43; "\r\n");  
    sb.append("Content-Disposition: form-data; name&＃61;\"username\"" &＃43; "\r\n");  
    sb.append("\r\n");  
    sb.append(username &＃43; "\r\n");  
  
    sb.append("--" &＃43; BOUNDARY &＃43; "\r\n");  
    sb.append("Content-Disposition: form-data; name&＃61;\"password\"" &＃43; "\r\n");  
    sb.append("\r\n");  
    sb.append(password &＃43; "\r\n");  
  
    sb.append("--" &＃43; BOUNDARY &＃43; "\r\n");  
    sb.append("Content-Disposition: form-data; name&＃61;\"file\"; filename&＃61;\"" &＃43; path &＃43; "\"" &＃43; "\r\n");  
    sb.append("Content-Type: image/pjpeg" &＃43; "\r\n");  
    sb.append("\r\n");  
  
    // 文件之前的数据  
    byte[] before &＃61; sb.toString().getBytes("UTF-8");  
    // 文件之后的数据  
    byte[] after &＃61; ("\r\n--" &＃43; BOUNDARY &＃43; "--\r\n").getBytes("UTF-8");  
  
    URL url &＃61; 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 &＃61; new Socket(url.getHost(), url.getPort());  
    OutputStream out &＃61; socket.getOutputStream();  
    PrintStream ps &＃61; 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&＃61;" &＃43; BOUNDARY);  
    ps.println("Content-Length: " &＃43; String.valueOf(before.length &＃43; file.length() &＃43; after.length));  
    ps.println("Host: 192.168.1.199:8080");  
      
    InputStream in &＃61; new FileInputStream(file);  
  
    // 写出数据  
    out.write(before);  
  
    byte[] buf &＃61; new byte[1024];  
    int len;  
    while ((len &＃61; in.read(buf)) !&＃61; -1)  
        out.write(buf, 0, len);  
  
    out.write(after);  
  
    in.close();  
    out.close();  
  
    return true;  
}