BufferedReader, PrintWriter를 이용한 파일 읽고 쓰기

• 원하는 파일을 읽고 저장하는 방법을 알아보자
• IO 클래스의 적합한 사용법을 배운다.
• FileReader와 FileWriter를 사용한다.

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import java.io.*; public class ReadAndWriteFromFile{    public void readFile(String fn) throws IOException{         FileReader fr=new FileReader(fn);         BufferedReader br=new BufferedReader(fr);         StringBuffer sb=new StringBuffer();         String temp="";         while((temp=br.readLine())!=null){             sb.append(temp+"\n");         }         System.out.println(sb.toString());         br.close();         fr.close();    }    public void readnwrite(String fn, boolean append) throws IOException{         String s=null;         FileWriter fw=new FileWriter(fn,append);//append true         PrintWriter pw=new PrintWriter(fw);//flush false         //PrintWriter pw=new PrintWriter(fw, true);//flush true         while((s=readbuff())!=null){   //CTRL+C             pw.println(s);             pw.flush();//PrintWriter(fw, true)일 때는 필요없다.         }         pw.close();         fw.close();    }    public String readbuff() throws IOException{         InputStreamReader isr=new InputStreamReader(System.in);         BufferedReader br=new BufferedReader(isr);         return br.readLine();     } }

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import java.io.*; public class ReadAndWriteFromFileMain {     public static void main(String[] args)     {         String fname="aaa.txt";         ReadAndWriteFromFile baw=new ReadAndWriteFromFile();         try{             baw.readnwrite(fname,false);//clear             //baw.readnwrite("aaa.txt",true);//append             baw.readFile(fname);         }catch(Exception ex){             System.out.println(ex);         }     } }