readandwrite.java

一些常用的java程序,包括swing.net.io,matrix等

package handlingOfFile;

public class ReadAndWrite
{
	public static void ReadFileByBufferedStream(String srcfile, String dstfile)
	{         //output to console may have wrong char, such as ??%%$$
		try
		{
			int i = 0;
			byte[] data;
			String str;
			int buflen = 32;
			data = new byte[buflen];
			java.io.FileInputStream fi = new java.io.FileInputStream(srcfile);
			java.io.BufferedInputStream bfi = new java.io.BufferedInputStream(fi, buflen);
			
			java.io.FileOutputStream fo = new java.io.FileOutputStream(dstfile);
			java.io.BufferedOutputStream bfo = new java.io.BufferedOutputStream(fo);
			
			while(bfi.read(data) != -1) //entire file
			{
				i++;
				str = new String(data);
				bfo.write(data);
				bfo.flush();
				System.out.print(str); // console may be 
			}//while
			bfo.flush();
			bfi.close();
			bfo.close();
			
		}//try
		catch(Exception e)
		{
			System.err.println("error found : ReadFile( "+srcfile+")");
			e.printStackTrace();
		}//catch		
		
	}//ReadFile
	
	//-----------------------------------------------------------------
	
	public static String ReadFileByBuffer(String url)
	{
		String str2 = new String();
		
		try
		{
			java.io.LineNumberReader lnr = new java.io.LineNumberReader(new java.io.FileReader(url));
			String str;
			for(str = lnr.readLine(); str != null; str = lnr.readLine())
			{
				str2 += str;
				str2 += "\n";
			}//for
			lnr.close();
		}//try
		catch(java.io.IOException e)
		{
			System.out.println("error found : ReadFileByReaderBuffer("+url+"). can't find file: "+url);
			//e.printStackTrace();
		}//catch
		
		return str2;
	}
	
	//-----------------------------------------------------------------
	
	public static boolean WriteFileByBuffer(String url, String content)
	{ //write a file, without checking if the file: url has been existed.
		try
		{
			/*java.io.File f = new java.io.File(url);
			if(f.exists())
			{
				System.err.println("filel "+ url + " is already exist!");
				System.out.println("Change a name,please input Y/y");
				System.out.println("Go On Write with the existed name, please input N/n");
			}*/
			java.io.BufferedWriter bw = new java.io.BufferedWriter(new java.io.FileWriter(url));
			String [] str = content.split("\n");
			for(int i = 0; i < str.length; i++)
			{
				bw.write(str[i]);
				bw.newLine();
				bw.flush();
			}
			bw.flush();  //if no flush(), you may not find the text in the file
			bw.close();
		}//try
		catch(java.io.IOException e)
		{
			System.err.println("error found : WriteFileByReaderBuffer("+url+")");
			e.printStackTrace();
			return false;
		}//catch
		
		return true;		
	}
	
	//-----------------------------------------------------------------
		
	public static void main(String[] args)
	{		
		java.awt.EventQueue.invokeLater
		(
			new   Runnable()   
			{ 
                public   void   run()   
                { 
                	
                   if(WriteFileByBuffer("test2.txt","hello\n"+"go\n"))
                   {
                	   System.out.println(ReadFileByBuffer("test2.txt"));
                   }
                } 
			}
		); //java.awt.EventQueue.invokeLater(---
	}//main()
}//ReadAndWrite