目录如何拷贝

同学你好！

如果要拷贝文件夹，同学需要判断目录是否存在，不存在要创建，文件不存在，创建文件，并拷贝文件内容，需要用到遍历和递归，老师这里写了一个小例子，同学可以参考学习一下：

/*
    将"E:/DTLFolder/ceshi"下的所有数据复制到"E:/DTLFolder/ceshi1"下
*/

import java.io.*;

public class ForDemo{
    final static String SOURCESTRING = "E:/DTLFolder/ceshi";
    final static String TARGETSTRING = "E:/DTLFolder/ceshi1";
    
    public static void main(String[] args){
        if(!(new File(SOURCESTRING)).exists()){
            System.out.println("源文件" + SOURCESTRING + "不存在，无法复制！");
            return;
        }else{
            if((new File(SOURCESTRING)).isFile()){
                copyFile(new File(SOURCESTRING),new File(TARGETSTRING));
            }else if((new File(SOURCESTRING)).isDirectory()){
                copyDirectory(SOURCESTRING,TARGETSTRING);
            }
        }
    }
    
    private static void copyFile(File sourceFile,File targetFile){
        if(!sourceFile.canRead()){
            System.out.println("源文件" + sourceFile.getAbsolutePath() + "不可读，无法复制！");
            return;
        }else{
            System.out.println("开始复制文件" + sourceFile.getAbsolutePath() + "到" + targetFile.getAbsolutePath());
            FileInputStream fis = null;
            BufferedInputStream bis = null;
            FileOutputStream fos = null;
            BufferedOutputStream bos = null;
            
            try{
                fis = new FileInputStream(sourceFile);
                bis = new BufferedInputStream(fis);
                fos = new FileOutputStream(targetFile);
                bos = new BufferedOutputStream(fos);
                int len = 0;
                while((len = bis.read()) != -1){
                    bos.write(len);    
                }
                bos.flush();
                
            }catch(FileNotFoundException e){
                e.printStackTrace();    
            }catch(IOException e){
                e.printStackTrace();
            }finally{
                try{
                    if(fis != null){
                        fis.close();    
                    }
                    if(bis != null){
                        bis.close();    
                    }
                    if(fos != null){
                        fos.close();    
                    }
                    if(bos != null){
                        bos.close();    
                    }
                    System.out.println("文件" + sourceFile.getAbsolutePath() + "复制到" + targetFile.getAbsolutePath() + "完成");
                }catch(IOException e){
                    e.printStackTrace();
                }
            }
        }
    }
    
    private static void copyDirectory(String sourcePathString,String targetPathString){
        if(!new File(sourcePathString).canRead()){
            System.out.println("源文件夹" + sourcePathString + "不可读，无法复制！");
            return;
        }else{
            (new File(targetPathString)).mkdirs();
            System.out.println("开始复制文件夹" + sourcePathString + "到" + targetPathString);
            File[] files = new File(sourcePathString).listFiles();
            for(int i = 0; i < files.length; i++){
                if(files[i].isFile()){
                    copyFile(new File(sourcePathString + File.separator + files[i].getName()),new File(targetPathString + File.separator + files[i].getName()));    
                }else if(files[i].isDirectory()){
                    copyDirectory(sourcePathString + File.separator + files[i].getName(),targetPathString + File.separator + files[i].getName());
                }    
            }
            System.out.println("复制文件夹" + sourcePathString + "到" + targetPathString + "结束");
        }
    }
}

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