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c# - 如何编写具有大小限制（100KB）的json文件，一旦大小交叉，写入新文件？

问题描述

我有一个blocking集合，其中填充了一些数据app1。

我已经订阅了那个blocking集合，需要用下面的案例写一个文件，

  1. 开始写文件。
  2. 如果文件大小超过 100kb，则关闭第一个文件并开始一个新文件。
  3. 如果没有来自 的数据app1，让我们说 1 分钟，然后关闭文件。

目前使用以下代码，我只能将每个blocking集合写入每个文件，如何继续我的上述要求，请建议。

class Program
{
    private static BlockingCollection<Message> messages = new BlockingCollection<Message>();
    private static void Producer()
    {
        int ctr = 1;
        while (true)
        {
            messages.Add(new Message { Id = ctr, Name = $"Name-{ctr}" });
            Thread.Sleep(1000);
            ctr++;
        }
    }

    private static void Consumer()
    {
        foreach (var message in messages.GetConsumingEnumerable())
        {
            Console.WriteLine(JsonConvert.SerializeObject(message));

            using (var streamWriter = File.CreateText(Path.Combine(@"C:\TEMP", $"File-{ DateTime.Now.ToString("yyyyMMddHHmmssfff")}.json")))
            {
                using (var writer = new JsonTextWriter(streamWriter))
                {
                    writer.Formatting = Formatting.Indented;
                    writer.WriteStartObject();
                    writer.WritePropertyName("Data");
                    writer.WriteStartArray();
                    writer.WriteRawValue(JsonConvert.SerializeObject(message));
                    writer.WriteEndArray();
                    writer.WriteEndObject();
                }
            }
        }
    }
    static void Main(string[] args)
    {
        var producer = Task.Factory.StartNew(() => Producer());
        var consumer = Task.Factory.StartNew(() => Consumer());
        Console.Read();
    }
}

标签： c#json.netblockingcollection

解决方案

这将获取任意大小的消息并将其划分为不同的 JSON 文件。您需要使用 maxchar 指定大小。在此之前，您必须像这样检查最后一个文件的大小，如果要创建新文件并划分消息，则必须传递相同的文件名和新大小。

using System;
using System.IO;
using System;
using System.Threading;
using System.Threading.Tasks;
using System.Collections.Concurrent;



using System.Collections;


using Newtonsoft.Json;
using System.Runtime.Remoting.Messaging;
using System.Text;

namespace Program
{
    class Program
    {
        public static string last_path = "";
        public static readonly string BYE = "bye";
        private static BlockingCollection<Message> messages = new BlockingCollection<Message>();
        private static void Producer()
        {
            int ctr = 1;
            while (true)
            {
                messages.Add(new Message { Id = ctr, Name = $"Name-{ctr}" });
                Thread.Sleep(1000);
                ctr++;
            }
        }

        private static void Consumer()
        {
            foreach (var message in messages.GetConsumingEnumerable())
            {
                Console.WriteLine(JsonConvert.SerializeObject(message));
                string json = JsonConvert.SerializeObject(message);
                int maxchar = 102400;
                if (last_path != "")
                {
                    long length = new FileInfo(last_path).Length;
                    if (length < maxchar)
                    {
                        maxchar = maxchar - unchecked((int)length);
                        dividefile(last_path, maxchar, json);
                    }

                    else

                    {
                        dividefile("", maxchar, json);

                    }
                }
                else
                {
                    dividefile("", maxchar, json);

                }

            }
        }

        public static void dividefile(string path, int maxchar, string message)
        {

            //FileStream fileStream = new FileStream(yourfile, FileMode.Open, FileAccess.Read);
            byte[] byteArray = Encoding.UTF8.GetBytes(message);

            MemoryStream stream = new MemoryStream(byteArray);

            using (StreamReader streamReader = new StreamReader(stream))
            {
                Int64 x1 = stream.Length;
                char[] fileContents = new char[maxchar];
                int charsRead = streamReader.Read(fileContents, 0, maxchar);

                // Can't do much with 0 bytes
                if (charsRead == 0)
                    throw new Exception("File is 0 bytes");

                while (charsRead > 0)
                {
                    x1 = x1 - maxchar;

                    if (x1 > 0)
                    {
                        string s = new string(fileContents);
                        if (path == "")
                        {
                            last_path = Path.Combine(@"C:\TEMP", $"File-{ DateTime.Now.ToString("yyyyMMddHHmmssfff")}.json");
                            path = "";
                        }
                        else
                        {
                            last_path = path;
                        }
                        AppendTransaction(last_path, s);
                        charsRead = streamReader.Read(fileContents, 0, maxchar);
                    }
                    else
                    {
                        int m = (int)(((x1 + maxchar) % maxchar));
                        string messagechunk = new string(fileContents, 0, m);
                        if (path == "")
                        {
                            last_path = Path.Combine(@"C:\TEMP", $"File-{ DateTime.Now.ToString("yyyyMMddHHmmssfff")}.json");
                            path = "";
                        }
                        else
                        {
                            last_path = path;
                        }

                        AppendTransaction(last_path, messagechunk);

                        charsRead = streamReader.Read(fileContents, 0, m);
                    }
                }
            }

        }

        private static void AppendTransaction(string path , string  transaction)
        {
             string filename = path;
            bool firstTransaction = !File.Exists(filename);

            JsonSerializer ser = new JsonSerializer();
            ser.Formatting = Formatting.Indented;
            ser.TypeNameHandling = TypeNameHandling.Auto;

            using (var fs = new FileStream(filename, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.Read))
            {
                Encoding enc = firstTransaction ? new UTF8Encoding(true) : new UTF8Encoding(false);

                using (var sw = new StreamWriter(fs, enc))
                using (var jtw = new JsonTextWriter(sw))
                {
                    if (firstTransaction)
                    {
                        sw.Write("[");
                        sw.Flush();
                    }

                    else
                    {
                        fs.Seek(-Encoding.UTF8.GetByteCount("]"), SeekOrigin.End);
                        sw.Write(",");
                        sw.Flush();
                    }

                    ser.Serialize(jtw, transaction);
                    sw.Write(']');
                }
            }


        }
        static void Main(string[] args)
        {
            var producer = Task.Factory.StartNew(() => Producer());
            var consumer = Task.Factory.StartNew(() => Consumer());
            Console.Read();
        }
        class Message
        {
            public int ProductorThreadID { get; set; }
            public int CustomerThreadID { get; set; }
            public string key { get; set; }
            public string content { get; set; }
            public string Name { get; internal set; }
            public int Id { get; internal set; }

            public bool endThread()
            {
                return string.Compare(key, Program.BYE) == 0;
            }

            public string ToString(bool isProductor)
            {
                return string.Format("{0} Thread ID {1} : {2}", isProductor ? "Productor" : "Customer",
                                                                isProductor ? ProductorThreadID.ToString() : CustomerThreadID.ToString(),
                                                                content);
            }
        }
    }
}

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