Android 实现图片转二进制流及二进制转字符串

我就废话不多说了，还是直接看代码吧

public static byte[] readStream(String imagepath) throws Exception {
  FileInputStream fs = new FileInputStream(imagepath);
  ByteArrayOutputStream outStream = new ByteArrayOutputStream();
  byte[] buffer = new byte[1024];
  int len = 0;
  while (-1 != (len = fs.read(buffer))) {
    outStream.write(buffer, 0, len);
  }
  outStream.close();
  fs.close();
  return outStream.toByteArray();
}

// 二进制转字符串
public static String byte2hex(byte[] b)
{
  StringBuffer sb = new StringBuffer();
  String tmp = "";
  for (int i = 0; i < b.length; i++) {
    tmp = Integer.toHexString(b[i] & 0XFF);
    if (tmp.length() == 1){
      sb.append("0" + tmp);
    }else{
      sb.append(tmp);
    }

  }
  return sb.toString();
}

补充知识：图片（bitmap）转化为byte[]，并上传到服务器

压缩为3:1bitmap

/**
   * 压缩bitmap
   *
   * @param bitmap
   * @return
   */
  private Bitmap compressBitmap(Bitmap bitmap) {
    // 创建操作图片用的matrix对象
    Matrix matrix = new Matrix();
    matrix.postScale((float) 300 / bitmap.getWidth(),
        (float) 100 / bitmap.getHeight());

    Log.e("", "bitmap_width" + bitmap.getWidth());
    Log.e("", "bitmap_height" + bitmap.getHeight());
    Bitmap compressBitmap = Bitmap.createBitmap(bitmap, 0, 0,
        bitmap.getWidth(), bitmap.getHeight(), matrix, true);
    return compressBitmap;
  }

上传压缩后的bitmap

private void eleSignature() {
    WritePadDialog writeTabletDialog = new WritePadDialog(
        this, new DialogListener() {
      public void refreshActivity(Object object) {
        Bitmap mSignBitmap = (Bitmap) object;
        mSignBitmap = compressBitmap(mSignBitmap);

//        Bitmap newsrcImage = mSignBitmap.copy(Bitmap.Config.RGB_565, true);
        saveBmp(mSignBitmap);
        Log.e("", "after bitmap_width:" + mSignBitmap.getWidth());
        Log.e("", "after bitmap_height:" + mSignBitmap.getHeight());
        File file = new File(file_name);
        Log.e("Jeny", "file.exists():" + file.exists());
        if (!file.exists()) {
          return;
        }
        byte[] eleSignatureData = null;
        try {
          eleSignatureData = InputStreamTOByte();
        } catch (IOException e) {

        }
        Log.e("Jeny", "eleSignatureData:" + eleSignatureData.length);
        if (eleSignatureData == null) {
          return;
        }

//        byte[] eleSignatureData = InputStreamTOByte();
//        byte[] eleSignatureData = Bitmap2Bytes(newsrcImage);
        mController.startSavingElecSignatureDataOfSDPay(SalesCollectActivity.this, voucherNo, eleSignatureData);
        mSignBitmap.recycle();
      }

    }
    );
    writeTabletDialog.setCanceledOnTouchOutside(false);
    writeTabletDialog.setOnKeyListener(new DialogInterface.OnKeyListener() {
      @Override
      public boolean onKey(DialogInterface dialogInterface, int keyCode, KeyEvent keyEvent) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
          return true;
        } else {
          return false; //默认返回 false
        }
      }
    });
    writeTabletDialog.show();
  }

  /**
   * 将InputStream转换成byte数组
   * <p/>
   * InputStream
   *
   * @return byte[]
   * @throws IOException
   */
  @SuppressWarnings("resource")
  public byte[] InputStreamTOByte() throws IOException {
    File file = new File(file_name);
    if (!file.exists()) {
      return null;
    }
    FileInputStream is = new FileInputStream(file_name);
    ByteArrayOutputStream outStream = new ByteArrayOutputStream();
    byte[] data = new byte[BUFFER_SIZE];
    int count = -1;
    while ((count = is.read(data, 0, BUFFER_SIZE)) != -1)
      outStream.write(data, 0, count);
    // data = null;
    byte[] alldata = outStream.toByteArray();

    /**top = new byte[62];
     for (int i = 0; i < 62; i++)
     {
     top[i] = alldata[i];
     }
     writefile(top_name, top);
     */
//    byte[] other = new byte[alldata.length - 62];
//    for (int i = 0; i < (alldata.length - 62); i++)
//    {
//      other[i] = alldata[i + 62];
//    }
    /*
     * String b =
		 * Environment.getExternalStorageDirectory().getPath()+"/other.txt";
		 * writefile(b, other);
		 */
    return alldata;
  }
  /**
   * @param bitmap 图片以bmp格式存储的方法
   */
  private void saveBmp(Bitmap bitmap) {
    if (bitmap == null)
      return;
    // 位图大小
    int nBmpWidth = bitmap.getWidth();
    int nBmpHeight = bitmap.getHeight();
    int DataSizePerLine = 40;
    // 图像数据大小
    int bufferSize = nBmpHeight * DataSizePerLine;
    try {
      // 存储文件名
      File file = new File(file_name);
      Log.i("SurFace", "filename:" + file_name);
      if (!file.exists()) {
        file.createNewFile();
      }
      FileOutputStream fileos = new FileOutputStream(file_name);
      // bmp文件头
      int bfType = 0x4d42;
      long bfSize = 14 + 40 + 8 + bufferSize;
      int bfReserved1 = 0;
      int bfReserved2 = 0;
      long bfOffBits = 14 + 40 + 8;
      // 保存bmp文件头
      writeWord(fileos, bfType);
      writeDword(fileos, bfSize);
      writeWord(fileos, bfReserved1);
      writeWord(fileos, bfReserved2);
      writeDword(fileos, bfOffBits);
      // bmp信息头
      long biSize = 40L;
      long biWidth = nBmpWidth;
      long biHeight = nBmpHeight;
      int biPlanes = 1;
      int biBitCount = 1;
      long biCompression = 0L;
      long biSizeImage = 0L;
      long biXpelsPerMeter = 0L;
      long biYPelsPerMeter = 0L;
      long biClrUsed = 0L;
      long biClrImportant = 0L;
      // 保存bmp信息头
      writeDword(fileos, biSize);
      writeLong(fileos, biWidth);
      writeLong(fileos, biHeight);
      writeWord(fileos, biPlanes);
      writeWord(fileos, biBitCount);
      writeDword(fileos, biCompression);
      writeDword(fileos, biSizeImage);
      writeLong(fileos, biXpelsPerMeter);
      writeLong(fileos, biYPelsPerMeter);
      writeDword(fileos, biClrUsed);
      writeDword(fileos, biClrImportant);
      // 调色板
      byte[] c = new byte[4];
      c[0] = 0;
      c[1] = 0;
      c[2] = 0;
      c[3] = 0;
      fileos.write(c);
      byte[] w = new byte[4];
      w[0] = (byte) 255;
      w[1] = (byte) 255;
      w[2] = (byte) 255;
      w[3] = 0;
      fileos.write(w);
      int wWidth = DataSizePerLine;
      // 像素扫描
      byte bmpData[] = new byte[bufferSize];
      for (int ibuf = 0; ibuf < bufferSize; ibuf++)
        bmpData[ibuf] = (byte) 0xff;
      int iByte = 0;
      int iCount = 0;
      byte bPix = 0;
      for (int nCol = nBmpHeight - 1, nRealCol = nBmpHeight; nCol > 0; nCol--, nRealCol--) {
        wWidth = DataSizePerLine;
        iCount = 0;
        iByte = 0;
        for (int wRow = 0; wRow < nBmpWidth; wRow++) {
          int clr = bitmap.getPixel(wRow, nCol);

          int r = (clr | 0xff00ffff) >> 16 & 0x00ff;
          int g = Color.green(clr);
          int b = Color.blue(clr);
          // byte a = (byte) Color.blue(clr);
          // byte b = (byte) Color.green(clr);
          // byte d = (byte) Color.red(clr);
          // System.out.println("r:"+r);
          if (r != 255 || g != 255 || b != 255)// 黑色
          {
            // bPix = (byte)(bPix & (0x7f>>iByte |
            // 0x7f<<(8-iByte)));
            bPix = (byte) (bPix & ~(byte) Math.pow(2, iByte));
            // System.out.println( " 黑色 " + bPix );
          } else {
            // bPix = (byte)(bPix & (0xff>>iByte |
            // 0xff<<(8-iByte)));
            bPix = (byte) (bPix | (byte) Math.pow(2, iByte));
            // System.out.println( " 白色 " + bPix);
          }
          if (iCount != 0 && iCount % 8 == 0) {
            bmpData[nRealCol * wWidth - wRow / 8] = bPix;
            iByte = 0;
          } else {
            iByte++;
          }
          iCount++;
          /*
           * //if(a==b && b==d && a>0) if (nRealCol%2 == 0) { //为白色
					 * bmpData[nRealCol * wWidth] = (byte)255; }else{ //为黑色
					 * bmpData[nRealCol * wWidth] = 0; }
					 */
          // Arrays.fill(x, value);
          /*
           * bmpData[nRealCol * wWidth + wByteIdex] = (byte) Color .b;
					 * bmpData[nRealCol * wWidth + wByteIdex + 1] = (byte) Color
					 * .green(clr); bmpData[nRealCol * wWidth + wByteIdex + 2] =
					 * (byte) Color .red(clr);
					 */
        }
      }
      // System.out.println( " iCount= " + iCount);
      /*
       * byte[] writeByte = new byte[bmpData.length]; for(int
			 * i=0;i<writeByte.length;i++){ writeByte[i] =
			 * bmpData[bmpData.length-i-1]; }
			 */
      fileos.write(bmpData);
      fileos.flush();
      fileos.close();
    } catch (FileNotFoundException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }
  protected void writeWord(FileOutputStream stream, int value)
      throws IOException {
    byte[] b = new byte[2];
    b[0] = (byte) (value & 0xff);
    b[1] = (byte) (value >> 8 & 0xff);

    stream.write(b);
  }

  protected void writeDword(FileOutputStream stream, long value)
      throws IOException {
    byte[] b = new byte[4];
    b[0] = (byte) (value & 0xff);
    b[1] = (byte) (value >> 8 & 0xff);
    b[2] = (byte) (value >> 16 & 0xff);
    b[3] = (byte) (value >> 24 & 0xff);

    stream.write(b);
  }

  protected void writeLong(FileOutputStream stream, long value)
      throws IOException {
    byte[] b = new byte[4];
    b[0] = (byte) (value & 0xff);
    b[1] = (byte) (value >> 8 & 0xff);
    b[2] = (byte) (value >> 16 & 0xff);
    b[3] = (byte) (value >> 24 & 0xff);

    stream.write(b);
  }

  /**
   * 压缩bitmap
   *
   * @param bitmap
   * @return
   */
  private Bitmap compressBitmap(Bitmap bitmap) {
    // 创建操作图片用的matrix对象
    Matrix matrix = new Matrix();
    matrix.postScale((float) 300 / bitmap.getWidth(),
        (float) 100 / bitmap.getHeight());

    Log.e("", "bitmap_width" + bitmap.getWidth());
    Log.e("", "bitmap_height" + bitmap.getHeight());
    Bitmap compressBitmap = Bitmap.createBitmap(bitmap, 0, 0,
        bitmap.getWidth(), bitmap.getHeight(), matrix, true);
    return compressBitmap;
  }

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