자바/자바 기본

자바 JAVA FILE COPY 파일 복사/수정 간단 예제

은은하게미친자 2022. 6. 17. 15:31
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* 파일 복사 예제

 

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package kr.co.obj;
 
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;
 
import javax.xml.crypto.Data;
 
public class FileTest2 {
 
    public static void main(String[] args) throws FileNotFoundException, IOException   {
        
        //=file 열어서 복사하기=============================================
        String rfilename = "tomboy.abc";
        String wfilename = "output.txt";
        
        FileReader fr     = null;        //주스트림.
        BufferedReader br = null;        //보조스트림
        
        FileWriter writer = null;   
        
        fr = new FileReader(rfilename);
        br = new BufferedReader(fr);        //생성자 안에 new해서 쓰는거 - 익명 클래스 일회적으로 사용하고 버려짐.
        
        writer = new FileWriter(wfilename);
 
        while(true) {
            int read = br.read();          // 읽을때 문자타입 , 바이트타입도 있움.
            
            if (read==-1)   // -1 if the end of the stream has been reached
                break;
 
            char c = (char)read;
        
            System.out.print(c);
            writer.write(c);
        }
        
        br.close();                                  //FIANLLY에 쓰면 조움
        writer.close(); //꼭 닫아줘야 파일 쓰기가 마무리됨! //FIANLLY에 쓰면 조움
        
        //=Files.copy 방식=============================================
        
        String filename = "tomboy.abcd";
        String filename1 = "tomboy.abcde";
        File orgfile  = new File(rfilename);
        File copyfile = new File(filename);
        
        
        //=Files.copy 방식=============================================
        Files.copy(orgfile.toPath(), copyfile.toPath());
        
        copyfile = new File(filename1);
        //=Files.copy 방식===Replace an existing file if it exists.
        Files.copy(orgfile.toPath(), copyfile.toPath(), StandardCopyOption.REPLACE_EXISTING);
    
        
    }
    
}
 cs

* 파일 수정 예제

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package kr.co.obj;
 
 
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;
 
public class FileTest3 {
    
    public static void main(String[] args) throws FileNotFoundException,IOException{
        /*
         * 파일을 쓸때 재 생성 되는것이 아니라
         * 문서뒤에 추가하여 사용하는 방법
         * new FileWriter(wname, true);  
         * true가 붙으면 추가가능함         */
        
        boolean stop = false;
        Scanner scan = new Scanner(System.in);
        
        String wname = "output.txt"; 
        FileWriter writer = new FileWriter(wname, true);
        // FileWriter 생성자 2번째 인자에 true를 넣으면 기존파일에 txt추가
        // false 일경우 기존 파일 삭제되고 처음 부터 입력.
        
        while(!stop) {
            System.out.println("아무 문자열이나 입력(종료는 00 입력)");
            String str = scan.nextLine();
            if(str.equals("00")) {
                stop = true;
                break;
            }
            writer.write("\n"+str);
        }        
        
        writer.close();
        
    }
 
}
 
 cs

 

 

 

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