Java呼叫pyzbar解析base64二維碼過程解析

阿新 • • 發佈：2020-08-20

一、環境配置

所有OS，建議使用python3.6；python2.7也可以，但在安裝過程中可能遇到升級pip等問題；請參考pyzbar官網https://pypi.org/project/pyzbar/

1.Ubuntu16.4

apt-get install libzbar0
pip install pyzbar
pip install Pillow

2.Centos7

yum install python-devel
yum install zbar-devel
yum install zbar

pip install Pillow
pip install pyzbar

3.Windows

pip install Pillow
pip install pyzbar

還需安裝Visual C++ Redistributable Packages for Visual Studio 2013，即從微軟官方下載的 vcredist_x64.exe程式

二、程式碼編寫

Java程式碼

UserController.java

package com.yang.springbootlucene.controller;

import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.io.ClassPathResource;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;

/**
 * @author:yjx
 * @description:
 * @date:2019/11/28 15:29
 */
@Slf4j
@RestController
@RequestMapping("/user")
public class UserController {

  @Value("${pyzbar.script}")
  private String scriptPath;

  private static final String BASE_64_PREFIX = "data:image/png;base64,";

  /**
   * 這種方式在原始碼中成功呼叫，但達成jar包後，找不到指令碼路徑，所以指令碼必須放在外面
   */
  @Deprecated
  private static String pyZbarScriptPath;
  /* static {
    ClassPathResource pathResource = new ClassPathResource("/script/my_py_zbar.py");
    try {
      pyZbarScriptPath = pathResource.getFile().getAbsolutePath();
    } catch (IOException e) {
      e.printStackTrace();
    }
  } */

  @RequestMapping("/cameraScanPyZbar")
  public Object cameraScanPyZbar(@RequestBody String base64) throws IOException {
    if (this.checkBase64Head(base64)) {
      //1.去掉base64字元的頭部
      String base64Str = this.cutHead(base64);

      //2.建立臨時檔案（由於圖片的base64字元太長，不支援直接以命令引數的形式傳遞，故將字串寫入臨時檔案，而後python程式讀取臨時檔案內容）
      String tempPath = "./" + Thread.currentThread().getName();
      File tempFile = new File(tempPath);
      FileWriter fileWriter = new FileWriter(tempFile,false);
      fileWriter.write(base64Str);
      fileWriter.flush();
      fileWriter.close();

      //3.呼叫pyzbar解析base64字串
      String plainText = PyZbarUtil.executePyzbar("python",scriptPath,tempFile.getAbsolutePath());

      //4.刪除臨時檔案
      tempFile.delete();
      System.err.println("--------->" + plainText);
      return plainText;
    } else {
      return "引數格式錯誤";
    }
  }

  /**
   * 校驗Base64值是否已規定的串開始
   *
   * @param base64
   * @return
   */
  private boolean checkBase64Head(String base64) {
    return base64.startsWith(BASE_64_PREFIX);
  }

  /**
   * Base64去頭
   *
   * @param base64
   * @return
   */
  private String cutHead(String base64) {
    return base64.replaceAll(BASE_64_PREFIX,"");
  }
}

PyZbarUtil.java

package com.yang.springbootlucene.controller;

import java.io.BufferedReader;
import java.io.InputStreamReader;

public final class PyZbarUtil {

  /**
   * 指令碼執行工具類
   *
   * @param lang    命令語言
   * @param scriptPath 指令碼絕對路勁
   * @param base64Path   base64檔案絕對路徑
   * @return
   */
  public static String executePyzbar(String lang,String scriptPath,String base64Path) {
    String[] arguments = new String[]{lang,base64Path};
    try {
      Process process = Runtime.getRuntime().exec(arguments);
      int re = process.waitFor();
      if (re == 0) {
        try (BufferedReader in = new BufferedReader(new InputStreamReader(process.getInputStream(),"GBK"));) {
          return in.readLine();
        }
      } else {
        System.err.println("指令碼呼叫失敗");
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
    return null;
  }
}

python指令碼my_py_zbar.py

# -*-coding:UTF-8-*-

import sys
import base64
from io import BytesIO
import pyzbar.pyzbar as pyzbar
from PIL import Image,ImageEnhance


'''將base64轉換為位元組流'''
def convert_base64_to_byte_stream(base64_str):
  # 1.解碼Base64字串
  img_data = base64.b64decode(base64_str)

  # 2.將節碼結果轉為位元組流
  byte_stream = BytesIO(img_data)
  return byte_stream


'''從將位元組流解析二維碼'''
def parse_byte_stream_qr_code(byte_stream):
  # 3.開啟位元組流得到圖片物件
  img = Image.open(byte_stream)

  img = ImageEnhance.Brightness(img).enhance(2.0) #增加亮度
  img = ImageEnhance.Contrast(img).enhance(4.0) #增加對比度
  # img = ImageEnhance.Sharpness(img).enhance(17.0) #銳利化
  # img = img.convert('L') #灰度化

  # img.show() # 播放圖片，供測試用

  # 4.呼叫pyzbar解析圖片中的二維碼
  barcodes = pyzbar.decode(img)

  # 5.列印解析結果
  return barcodes[0].data.decode("utf-8")


def main(argv):
#  print(parse_byte_stream_qr_code(convert_base64_to_byte_stream(argv[1])))
  print(parse_byte_stream_qr_code(convert_base64_to_byte_stream(open(argv[1]).readline())))


if __name__ == "__main__":
  main(sys.argv)

三、主要坑點