编写一个程序将d:\java目录下的所有.java文件复制到d:\jad目录下,并将原来文件的扩展名从.java改为.jad

蔚落 2022-03-06 01:34 122阅读 0赞

这个的重点就是File.listFile()的参数FilenameFilter()这个接口的accept()方法，该方法作用是根据过滤条件查找对应的File数组。

import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.FilenameFilter;
    import java.io.IOException;
    
    public class FileCopy { 
    	public static void main(String[] args) throws IOException { 
    		String src = "d:/java";
    		File file = new File(src);
    		if (!file.exists()) { 
    			throw new FileNotFoundException("目录不存在");
    		}
    		File[] files = file.listFiles(new FilenameFilter() { 
    
    			@Override
    			public boolean accept(File dir, String name) { 
    				return name.endsWith(".java");
    			}
    		});
    		System.out.println(files.length);
    		File deskdir = new File("d:/jad");
    		if (!deskdir.exists()) { 
    			deskdir.mkdir();
    		}
    		for (File file2 : files) { 
    			FileInputStream fis = new FileInputStream(file2);
    			String destFileName = file2.getName().replace(".java", ".jad");
    			System.out.println(destFileName);
    			FileOutputStream fos = new FileOutputStream(new File(deskdir,destFileName));
    			copy(fis, fos);
    			fis.close();
    			fos.close();
    			System.out.println("复制完成");
    		}
    	}
    
    	private static void copy(FileInputStream fis, FileOutputStream fos)
    			throws IOException { 
    		int len = 0;
    		byte[] bytes = new byte[1024];
    		while ((len = fis.read(bytes)) != -1) { 
    			fos.write(bytes, 0, len);
    		}
    
    	}
    }