我对C#中的文件有点新,我遇到了问题.从文件读取并复制到另一个文件时,最后一块文本没有被写入.以下是我的代码:
StringBuilder sb = new StringBuilder(8192);
string fileName = "C:...rest of path...inputFile.txt";
string outputFile = "C:...rest of path...outputFile.txt";
using (StreamReader reader = File.OpenText(fileName))
{
char[] buffer = new char[8192];
while ((reader.ReadBlock(buffer, 0, buffer.Length)) != 0)
{
foreach (char c in buffer)
{
//do some function on char c...
sb.Append(c);
}
using (StreamWriter writer = File.CreateText(outputFile))
{
writer.Write(sb.ToString());
}
}
}
我的目标是以缓冲方式读取和写入文本文件.我将通过以下方式实现Java中的某些功能:
public void encrypt(File inputFile, File outputFile) throws IOException
{
BufferedReader infromfile = null;
BufferedWriter outtofile = null;
try
{
String key = getKeyfromFile(keyFile);
if (key != null)
{
infromfile = new BufferedReader(new FileReader(inputFile));
outtofile = new BufferedWriter(new FileWriter(outputFile));
char[] buffer = new char[8192];
while ((infromfile.read(buffer, 0, buffer.length)) != -1)
{
String temptext = String.valueOf(buffer);
//some changes to temptext are done
outtofile.write(temptext);
}
}
}
catch (FileNotFoundException exc)
{
} // and all other possible exceptions
}
你能帮我找出问题的根源吗?
如果您认为可能有更好的方法来实现带有文本文件的缓冲i / o,我将非常感谢您的建议.
解决方法:
有几个“陷阱”:
> c无法更改(它是foreach迭代变量),您需要复制它才能在写入之前进行处理
>你必须跟踪缓冲区的大小,ReadBlock用字符填充它会使你的输出变脏
像这样更改代码看起来像是有效的:
//extracted from your code
foreach (char c in buffer)
{
if (c == (char)0) break; //GOTCHA #2: maybe you don't want NULL (ascii 0) characters in your output
char d = c; //GOTCHA #1: you can't change 'c'
// d = SomeProcessingHere();
sb.Append(d);
}