Python-对象与json互转-json读写-文件读写

1.json

JSON(JavaScript Object Notation) 是一种轻量级的数据交换格式。 易于人阅读和编写。同时也易于机器解析和生成。 它基于JavaScript Programming Language, Standard ECMA-262 3rd Edition - December 1999的一个子集。 JSON采用完全独立于语言的文本格式，但是也使用了类似于C语言家族的习惯（包括C, C++, C#, Java, JavaScript, Perl, Python等）。 这些特性使JSON成为理想的数据交换语言。

2.类对象序列化

# 写文件
def _WriteFile(filename, strData):
    data = strData.encode('UTF-8');

    # 打开一个文件
    fw = open(filename, "wb");
    fw.write(data);
    # 关闭打开的文件
    fw.close();

# 读文件
def _ReadFile(filename):
    # 读取数据
    data = None;
    with open(filename, 'rb') as fr:
        data = fr.read();

    # 编码转换
    try:
        strData = str(data, 'utf-8');
        return strData;
    except:
        try:
            strData = str(data, 'GBK');
            return strData;
        except Exception as e:
            try:
                strData = str(data, 'latin1');
                return strData;
            except Exception as e:
                print(filename);
                pass;
            pass;
    return None;
   
 class AppPara:
    def __init__(self):
        self.svg_show_url = "";  # svg显示的二维码网址
        self.svg_show_local_full_filename = "";  # svg结果服务器保存路径
        self.svg_download_result_full_filename = "";  # 压缩包结果保存路径
        self.svg_upload_para_full_filename = "";  # 程序初始化压缩包路径
        self.svg_color_table_full_filename = "";  # 色表文件路径

    
    def DumpFile(self, filename):
        # 类对象转为json字符串
        data = json.dumps(self, default=lambda obj: obj.__dict__, ensure_ascii=False);

        # 写入文件
        _WriteFile(filename, data);

    def LoadFile(self, filename):
        # 读取文件数据
        data = _ReadFile(filename);
        if data is None:
            return False;

        # 字典对象转数据
        objDict = json.loads(data);
        self.__dict__.update(objDict);

3.调用exe进行数据交换

import json
import os
import subprocess
import shutil
import uuid
from loguru import logger


# 写文件
from SvgProcess.ACodeTimer import CodeTimer


def _WriteFile(filename, strData):
    data = strData.encode('UTF-8');

    # 打开一个文件
    fw = open(filename, "wb");
    fw.write(data);
    # 关闭打开的文件
    fw.close();


# 读文件
def _ReadFile(filename):
    # 读取数据
    data = None;
    with open(filename, 'rb') as fr:
        data = fr.read();

    # 编码转换
    try:
        strData = str(data, 'utf-8');
        return strData;
    except Exception as e:
        try:
            strData = str(data, 'GBK');
            return strData;
        except Exception as e:
            try:
                strData = str(data, 'latin1');
                return strData;
            except Exception as e:
                logger.error("PolygonMultiCenter _ReadFile:" + str(e));
                print(filename);
    return None;


# 将文件序列化为json字符串
def ToJson(tmpParaFilename, pathList, colorAreaDictNum, textPtWidthHeightMMInfoFilename, resultJsonFilename):
    # 抽取路径对象
    pathJsonObjList = [];
    for pathObj in pathList:
        pathJsonObj = {
            "Index": pathObj.m_Index,
            "PointsMM": pathObj.m_pointsMM,
            "ColorTableIndexText": pathObj.m_ColorTableIndexText
        };
        pathJsonObjList.append(pathJsonObj);

    # 构建json对象
    jsonObj = {
        "colorAreaDictNum": str(colorAreaDictNum),
        "textPtWidthHeightMMInfoFilename": textPtWidthHeightMMInfoFilename,
        "pathJsonObjList": pathJsonObjList,
        "resultJsonFilename": resultJsonFilename
    };

    # 类对象转为json字符串
    data = json.dumps(jsonObj);

    # 写入文件
    _WriteFile(tmpParaFilename, data);
    pass;


def ComputeExe(svgfilename, pathList, colorAreaDictNum):
    # 构建json文件和字体信息文件
    rootPath = os.path.dirname(__file__);
    loc_json_fmt = r"{}/tmp/" + str(uuid.uuid1()).replace("-", "") + ".json";  # 参数文件
    loc_json_filename = loc_json_fmt.format(rootPath);
    loc_json_filename = loc_json_filename.replace("\\", "/");

    loc_textPtWH_fmt = r"{}/TextPtWidthHeightMMInfo.json";  # 文本宽高信息
    loc_textPtWH_filename = loc_textPtWH_fmt.format(rootPath);
    loc_textPtWH_filename = loc_textPtWH_filename.replace("\\", "/");

    result_json_fmt = r"{}/tmp/" + str(uuid.uuid1()).replace("-", "") + "-PMC.json";  # 标注结果
    result_json_filename = result_json_fmt.format(rootPath);
    result_json_filename = result_json_filename.replace("\\", "/");

    # 生成参数文件
    ToJson(loc_json_filename, pathList, colorAreaDictNum, loc_textPtWH_filename, result_json_filename);

    _Timer = CodeTimer("计算时间");
    exe_fmt = r"{}/PolygonMultiCenter/PolygonMultiCenter.exe";  # 可执行文件
    exe_filename = exe_fmt.format(rootPath);
    exe_filename = exe_filename.replace("\\", "/");

    # 调用第三方程序实现多点标注
    _command_str = "\"" + exe_filename + "\"" + " \"" + loc_json_filename + "\""  # 编辑命令行
    ex = subprocess.Popen(_command_str, stdout=subprocess.PIPE, shell=True);
    out, err = ex.communicate();
    status = ex.wait();

    #_Timer.End();

    if not os.path.exists(result_json_filename):
        logger.error("结果未生成:"+svgfilename);
        return None;

    # 读取结果
    data = _ReadFile(result_json_filename)
    labelTextList = json.loads(data);

    # 删除临时文件
    os.remove(loc_json_filename);
    os.remove(result_json_filename);
    return labelTextList;

4.总结

JSON 是轻量级的文本数据交换格式，对程序员比较友好。