AndroidHttp实现文件的上传和下载

  /**
   * @param mContext 上下文
   * @param targetUrl 文件上传地址
   * @param filePath 文件路径
   */
  public void uploadFile(final Activity mContext, String targetUrl, final String filePath) {

    System.out.println("targetUrl: " + targetUrl + " filePath: " + filePath);

    if (TextUtils.isEmpty(filePath)) {
      Toast.makeText(mContext, "文件不存在", Toast.LENGTH_SHORT).show();
      return;
    }

    final PostMethod filePost = new PostMethod(targetUrl) {//这个用来中文乱码
      public String getRequestCharSet() {
        return "UTF-8";
      }
    };

    try {

      final HttpClient client = new HttpClient();

      File file = new File(filePath);

      if (file.exists() && file.isFile()) {

        long fileSize = file.length();

        if (fileSize >= 5 * 1024 * 1024) {
          Toast.makeText(mContext, "文件不得大于5M", Toast.LENGTH_SHORT).show();
          return;
        }

      } else {
        Toast.makeText(mContext, "文件不存在", Toast.LENGTH_SHORT).show();

        return;
      }

      // 上传文件和参数
      Part[] parts = new Part[]{new CustomFilePart(file.getName(), file),
          new StringPart("filename", file.getName(), "UTF-8")};
      filePost.setRequestEntity(new MultipartRequestEntity(parts, filePost.getParams()));

      new Thread(new Runnable() {

        @Override
        public void run() {

          int statuscode = 0;

          try {
            statuscode = client.executeMethod(filePost);
          } catch (IOException e) {
            e.printStackTrace();
          }

          final int finalStatuscode = statuscode;

          mContext.runOnUiThread(new Runnable() {

            @Override
            public void run() {
              if (finalStatuscode == HttpStatus.SC_OK) {
                Toast.makeText(mContext, "上传成功", Toast.LENGTH_SHORT).show();
              } else {
                Toast.makeText(mContext, "上传失败", Toast.LENGTH_SHORT).show();
              }
            }
          });
        }

      }).start();

    } catch (Exception ex) {
      ex.printStackTrace();
    }
  }

 final PostMethod filePost = new PostMethod(targetUrl) {//这个用来中文乱码
      public String getRequestCharSet() {
        return "UTF-8";
      }
    };

 /**
 * 解决中文文件名乱码
 */
public class CustomFilePart extends FilePart {
  public CustomFilePart(String filename, File file)
      throws FileNotFoundException {
    super(filename, file);
  }

  protected void sendDispositionHeader(OutputStream out) throws IOException {
    super.sendDispositionHeader(out);
    String filename = getSource().getFileName();
    if (filename != null) {
      out.write(EncodingUtil.getAsciiBytes(FILE_NAME));
      out.write(QUOTE_BYTES);
      out.write(EncodingUtil.getBytes(filename, "UTF-8"));
      out.write(QUOTE_BYTES);
    }
  }
}

Part[] parts = new Part[]{new CustomFilePart(file.getName(), file),
          new StringPart("filename", file.getName(), "UTF-8")};
filePost.setRequestEntity(new MultipartRequestEntity(parts, filePost.getParams()));

  /**
   * @param urlStr  文件地址
   * @param path   文件保存路径
   * @param fileName 文件名
   * @return 文件的绝对路径
   */
  public String downFile(String urlStr, String path, String fileName) {

    InputStream inputStream = null;
    String filePath = null;

    try {
      FileUtils fileUtils = new FileUtils();
      //判断文件是否存在
      if (fileUtils.isFileExist(path + fileName)) {
        System.out.println("exits");
        filePath = SDPATH + path + fileName;
      } else {
        //得到io流
        inputStream = getInputStreamFromURL(urlStr);
        //从input流中将文件写入SD卡中
        File resultFile = fileUtils.write2SDFromInput(path, fileName, inputStream);
        if (resultFile != null) {

          filePath = resultFile.getPath();
        }
      }
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      try {
        if (inputStream != null)
          inputStream.close();
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
    return filePath;
  }

  /**
   * 根据URL得到输入流
   *
   * @param urlStr
   * @return
   */
  public InputStream getInputStreamFromURL(String urlStr) {

    HttpURLConnection urlConn;
    InputStream inputStream = null;
    try {
      url = new URL(urlStr);
      urlCOnn= (HttpURLConnection) url.openConnection();
      inputStream = urlConn.getInputStream();

    } catch (Exception e) {
      e.printStackTrace();
    }

    return inputStream;
  }

/**
   * 将一个InputStream里面的数据写入到SD卡中
   *
   * @param path 文件保存路径
   * @param fileName 文件保存的名字
   * @param input 文件输入流
   * @return 文件
   */
  public File write2SDFromInput(String path, String fileName,
                 InputStream input) {
    File file = null;
    OutputStream output = null;
    try {
      // 创建文件夹
      createSDDir(path);
      // 创建文件
      file = createSDFile(path + fileName);

      // 开启输出流，准备写入文件
      output = new FileOutputStream(file);
      // 缓冲区
      byte[] buffer = new byte[FILESIZE];
      int count;
      while ((count = input.read(buffer)) != -1) {
        // 这里，请一定按该方式写入文件，不然时而会出现文件写入错误，数据丢失问题
        output.write(buffer, 0, count);
      }
      output.flush();
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      try {
        output.close();
        input.close();
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
    return file;
  }

 while ((count = input.read(buffer)) != -1) {
 // 这里，请一定按该方式写入文件，不然时而会出现文件写入错误，数据丢失问题
 output.write(buffer, 0, count);
}