我已将数据保存BinaryWriter在文件中。
现在我想使用从该文件（从特定位置开始）读取数据BinaryReader。
在写入文件时，我在文件中间添加了一个字符串“BREAK”。
我想在 C# 中从0 到“BREAK”之前和“BREAK”之后读取文件的结尾。请帮我。
问问题
1873 次
2 回答
1
BinaryWriter用于编写非人类可读的格式，因此是binary。例如，如果你想写原始类型，你可以把它们写成它们的字节表示（比如布尔值）
因此，对于写入/读取人类可读文件，您可以只使用StreamReader/ StreamWriter。这会容易得多。
使用 StreamReader
下面的代码片段根据您的规范工作，但如果您想改进其算法或其他任何内容，它只是一个指南。我还强烈建议您只使用StreamWriter. 但下面的代码使用BinaryWriter.
namespace _16953330
{
class Program
{
static void Main(string[] args)
{
string input =
@"The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.
fox jumps over the lazy dfox jumps over the lazy dBREAK fox jumps over the lazy dfox jumps over the lazy d
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.";
using (var stream = new FileStream("file.txt", FileMode.OpenOrCreate))
{
using (var writer = new BinaryWriter(stream)) //why use a BinaryWriter if you're gonna write in a human-readable format?
{
writer.Write(input);
}
}
string firstPart = string.Empty;
string secondPart = string.Empty;
StringBuilder sb = new StringBuilder();
using (var stream = new FileStream("file.txt", FileMode.OpenOrCreate))
{
using (var reader = new StreamReader(stream))
{
string line;
while (!string.IsNullOrEmpty(line = reader.ReadLine()))
{
int indexOfBreak = line.IndexOf("BREAK");
if (indexOfBreak == -1)
{
sb.Append(line);
}
else
{
string untilBeforeBREAK = line.Substring(0, indexOfBreak);
sb.Append(untilBeforeBREAK);
//remove the first 2 characters in the file as the BinaryWriter
//writes the length of the bytes should a BinaryReader expect
//(if ever you want to use a binary reader which I don't understand
//because you are reading a HUMAN READABLE file)
firstPart = sb.Remove(0,2).ToString();
sb.Clear();
string breakUpToTheEnd = string.Empty;
sb.Append(line.Substring(indexOfBreak));
sb.Append(reader.ReadToEnd());
secondPart = sb.ToString();
}
}
}
}
Console.WriteLine(firstPart);
Console.WriteLine(Environment.NewLine);
Console.WriteLine(secondPart);
}
}
}
使用 BinaryReader
但如果你真的坚持使用BinaryReader，BinaryWriter这里有一个解决方案。
namespace _16953330
{
class Program
{
static void Main(string[] args)
{
byte[] input = Encoding.ASCII.GetBytes(
@"I have saved data using BinaryWritter in a file. I have saved data using BinaryWritter in a file. I have saved data using BinaryWritter in a file. I have saved data using BinaryWritter in a file. I have saved data using BinaryWritter in a file. I have saved data using BinaryWritter in a file. I have saved data using BinaryWritter in a file. I have saved data using BinaryWritter in a file. I have saved data using BinaryWritter in a file. I have saved data using BinaryWritter in a file. I have saved data using BinaryWritter in a file. I have saved data using BinaryWritter in a file. I have saved data using BinaryWritter in a file. I have saved data using BinaryWritter in a file. I have saved data using BinaryBREAKWritter in a file. I have saved data using BinaryWritter in a file. I have saved data using BinaryWritter in a file. I have saved data using BinaryWritter in a file. "); //just for sampling purposes, considering that what you write is NON-human-readable
using (var stream = new FileStream("somefile.exe", FileMode.OpenOrCreate))
{
using (var writer = new BinaryWriter(stream))
{
writer.Write(input);
}
}
byte[] firstPart = null;
byte[] secondPart = null;
StringBuilder sb = new StringBuilder();
string breaker = "BREAK";
List<byte> byteList = new List<byte>();
using (var stream = new FileStream("somefile.exe", FileMode.OpenOrCreate))
{
using (var reader = new BinaryReader(stream))
{
while (reader.BaseStream.Position != reader.BaseStream.Length)
{
byte currentByte;
currentByte = reader.ReadByte();
if (currentByte == 'B')
{
byteList.Add(currentByte);
for (int i = 1; i < breaker.Length; i++)
{
currentByte = reader.ReadByte();
byteList.Add(currentByte);
//if the succeeding characters match the characters after B in BREAK
if ((char)currentByte == breaker[i] && i > 1)
{
byteList.RemoveAt(byteList.Count - 1);
if (i == breaker.Length - 1)
{
//if the for loop reaches its end and matches all characters in BREAK
//remove B (which was added above) and K (added last)
byteList.RemoveAt(byteList.Count - 1);
byteList.RemoveAt(byteList.Count - 1);
firstPart = byteList.ToArray();
byteList.Clear();
}
}
}
}
else
{
byteList.Add(currentByte);
}
}
secondPart = byteList.ToArray();
}
}
Console.WriteLine(firstPart);
Console.WriteLine(Environment.NewLine);
Console.WriteLine(secondPart);
}
}
}
于 2013-06-06T04:23:45.453 回答
0
BinaryReader 逐字节或逐字符读取。您必须阅读每个字符并尝试检查您正在寻找的组合。如果找到“B”，则检查下一个是否为“R”，如果是，则检查下一个是否为“E”，依此类推。也可能有一些很好的算法可用于此。
于 2013-06-06T03:48:23.900 回答