Android上传下载文件（图片）

来源：互联网发布：java程序员的工作内容编辑：程序博客网时间：2024/06/05 17:40
这里写是Android下上传下载文件，需要服务器端相应的程序配合，使用的是POST方法。Android客户端代码如下：
import java.io.BufferedReader;import java.io.ByteArrayOutputStream;import java.io.DataOutputStream;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.net.HttpURLConnection;import java.net.URL;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.util.Log;public class NetFileGetPost {/** * 从服务器读取文件 * @param path    文件保存的路径 * @param urlPath 文件在服务器的位置 * @return * @throws Exception */public static Bitmap readFromUri(String path, String urlPath)throws Exception {Log.d("debug","start read pic " + urlPath);URL url = new URL(urlPath);byte[] d = null;/** * 建立连接 */HttpURLConnection conn = (HttpURLConnection) url.openConnection();conn.setRequestMethod("POST");conn.setConnectTimeout(3 * 1000);/** * 得到连接状态 */int code = conn.getResponseCode();Log.d("debug","code = " + code);if (code == 200) {/** * 首先得到输入流，然后从输入流中写出数据到一个byte数组中，利用BitmapFactory工厂方法通过字节数组来得到 * 一个bitmap对象，最后利用FileOutputStream将bitmap对象转化成一个.png图片，存放在PIC_PATH中 */InputStream in = conn.getInputStream();d = readStream(path, in);if (d == null) {Log.w("debug","PicUtils --- >>> d == null");return null;}Bitmap bit = BitmapFactory.decodeByteArray(d, 0, d.length);File file = new File(path);if (!file.exists()) {file.createNewFile();}FileOutputStream out = new FileOutputStream(file);bit.compress(Bitmap.CompressFormat.JPEG, 100, out);conn.disconnect();out.close();in.close();return bit;} else {Log.w("debug","get Image is wrong");}return null;}private static byte[] readStream(String path, InputStream inStream) throws Exception {        if (!createFile(path)) {            Log.e("debug","create file path is not allow");            return null;        }        ByteArrayOutputStream outstream = new ByteArrayOutputStream();        byte[] buffer = new byte[1024];        int len = -1;        while ((len = inStream.read(buffer)) != -1) {            outstream.write(buffer, 0, len);        }        outstream.close();        return outstream.toByteArray();    }/** * 创建文件 */private static boolean createFile(String path) {File file = new File(path);if (file.exists()) {file.delete();}try {file.createNewFile();return true;} catch (IOException e) {e.printStackTrace();return false;}}/**  * 上传文件到服务器     * @param urlPath  网络地址      * @param picPath  该图片所在文件夹位置      * @功能 上传图片，我的服务端是是用php写的      */        public static String uploadPic(String urlPath, String picPath) {          DataOutputStream dos = null;    // 往服务端写入数据的输出流                  try {              Log.d("debug","start upload pic " + urlPath);              String end = "\r\n";    // 前面这些都是写html文件的头文件，固定的，不用去管              String twoHyphens = "--";              String boundary = "*****";            URL url = new URL(urlPath);              HttpURLConnection httpURLConnection = (HttpURLConnection) url                      .openConnection();            httpURLConnection.setChunkedStreamingMode(20 * 1024);// 文件大小20K            httpURLConnection.setDoInput(true);              httpURLConnection.setDoOutput(true);              httpURLConnection.setUseCaches(false);  // 这个地方不使用缓存              httpURLConnection.setRequestMethod("POST");              httpURLConnection.setRequestProperty("Connection", "Keep-Alive");              httpURLConnection.setRequestProperty("Charset", "UTF-8");              httpURLConnection.setRequestProperty("Content-Type",                      "multipart/form-data;boundary=" + boundary);              dos = new DataOutputStream(httpURLConnection.getOutputStream());              dos.writeBytes(twoHyphens + boundary + end);              dos.writeBytes("Content-Disposition: form-data; name=\"uploadedfile\"; filename=\""                      + picPath.substring(picPath.lastIndexOf("/") + 1)                      + "\";"                      + end);              dos.writeBytes(end);              FileInputStream fis = new FileInputStream(picPath);              byte[] buffer = new byte[1024 * 2];              int count = 0;              while ((count = fis.read(buffer)) != -1) {                  dos.write(buffer, 0, count);              }              fis.close();            dos.writeBytes(end);              dos.writeBytes(twoHyphens + boundary + twoHyphens + end);              dos.flush();                  BufferedReader reader = new BufferedReader(new InputStreamReader(                      httpURLConnection.getInputStream()));              String result = reader.readLine();  // 这个是得到上传图片的结果              Log.d("debug","PicUtils --- >>> result = " + result);              reader.close();              httpURLConnection.disconnect();              return result;          } catch (Exception e) {              e.printStackTrace();              return null;          } finally {              if (dos != null) {                  try {                      dos.close();                  } catch (IOException e) {                      e.printStackTrace();                  }              }          }      } }
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