读取写入文件

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.io.File;
import java.io.Reader;

public class OperatingString ...{
    static String str = "";

    public static String operating() ...{
        //
        String fileName = "C:/Documents and Settings/pwj/Desktop/JavaScript/drags.js";//原文件路径
        String fileNewName="C:/Documents and Settings/pwj/Desktop/JavaScript/new/";//换行代替；后的新文件路径
        String fileNameTwo=null;
        StringBuffer newFileName=null;
        FileReader fileReader = null;
        BufferedReader bufferedReader = null;
        //File file = null;
        FileWriter fileWriter=null;
        try ...{
            //file = new File("aa.txt");
            int j=fileName.lastIndexOf(92);
            fileNameTwo=fileName.substring(j+1,fileName.length());
            newFileName=new StringBuffer(fileNewName);
            fileNewName=newFileName.append(fileNameTwo).toString();
            fileReader = new FileReader(fileName);
            fileWriter= new FileWriter(fileNewName);
            bufferedReader = new BufferedReader(fileReader);
            String strT = null;
            while ((strT = bufferedReader.readLine()) != null) ...{
                System.out.println(" ____________ strT is "+strT);
                str += strT;
            }
            str = str.replace(";", " ");
            fileWriter.write(str);            
            
        } catch (Exception e) ...{
            e.printStackTrace();
            throw new RuntimeException(" ______________ throws "
                    + e.getMessage() + " exception");
        } finally ...{
            try ...{
                if (bufferedReader != null) ...{
                    fileReader.close();
                }
                if (fileReader != null) ...{
                    bufferedReader.close();
                }
                if(fileWriter !=null)...{
                    fileWriter.close();
                }
                
            } catch (IOException e) ...{
                e.printStackTrace();
                throw new RuntimeException(" ______________ throws "
                        + e.getMessage() + " exception");
            }

        } 
        return str;

    }

    
    public static void main(String[] args) ...{
        System.out.println(" _________ reade a.txt the result is "
                + operating());

    }

}